mirror of https://github.com/perkeep/perkeep.git
2777 lines
82 KiB
Go
2777 lines
82 KiB
Go
// mgo - MongoDB driver for Go
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//
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// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net>
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this
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// list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package mgo
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import (
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"crypto/md5"
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"encoding/hex"
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"errors"
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"fmt"
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"camlistore.org/third_party/labix.org/v2/mgo/bson"
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"math"
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"reflect"
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"runtime"
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"sort"
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"strconv"
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"strings"
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"sync"
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"time"
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)
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type mode int
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const (
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Eventual mode = 0
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Monotonic mode = 1
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Strong mode = 2
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)
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// When changing the Session type, check if newSession and copySession
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// need to be updated too.
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type Session struct {
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m sync.RWMutex
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cluster_ *mongoCluster
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socket *mongoSocket
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socketIsMaster bool
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slaveOk bool
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consistency mode
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queryConfig query
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safeOp *queryOp
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syncTimeout time.Duration
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urlauth *authInfo
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auth []authInfo
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}
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type Database struct {
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Session *Session
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Name string
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}
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type Collection struct {
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Database *Database
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Name string // "collection"
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FullName string // "db.collection"
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}
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type Query struct {
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m sync.Mutex
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session *Session
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query // Enables default settings in session.
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}
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type query struct {
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op queryOp
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prefetch float64
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limit int32
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}
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type getLastError struct {
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CmdName int "getLastError"
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W interface{} "w,omitempty"
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WTimeout int "wtimeout,omitempty"
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FSync bool "fsync,omitempty"
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J bool "j,omitempty"
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}
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type Iter struct {
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m sync.Mutex
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gotReply sync.Cond
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session *Session
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docData queue
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err error
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op getMoreOp
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prefetch float64
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limit int32
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pendingDocs int
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docsBeforeMore int
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timeout time.Duration
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timedout bool
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}
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var ErrNotFound = errors.New("not found")
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const defaultPrefetch = 0.25
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// Dial establishes a new session to the cluster identified by the given seed
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// server(s). The session will enable communication with all of the servers in
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// the cluster, so the seed servers are used only to find out about the cluster
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// topology.
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//
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// Dial will timeout after 10 seconds if a server isn't reached. The returned
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// session will timeout operations after one minute by default if servers
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// aren't available. To customize the timeout, see DialWithTimeout
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// and SetSyncTimeout.
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//
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// This method is generally called just once for a given cluster. Further
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// sessions to the same cluster are then established using the New or Copy
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// methods on the obtained session. This will make them share the underlying
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// cluster, and manage the pool of connections appropriately.
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//
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// Once the session is not useful anymore, Close must be called to release the
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// resources appropriately.
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//
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// The seed servers must be provided in the following format:
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//
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// [mongodb://][user:pass@]host1[:port1][,host2[:port2],...][/database][?options]
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//
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// For example, it may be as simple as:
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//
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// localhost
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//
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// Or more involved like:
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//
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// mongodb://myuser:mypass@localhost:40001,otherhost:40001/mydb
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//
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// If the port number is not provided for a server, it defaults to 27017.
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//
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// The username and password provided in the URL will be used to authenticate
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// into the database named after the slash at the end of the host names, or
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// into the "admin" database if none is provided. The authentication information
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// will persist in sessions obtained through the New method as well.
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//
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// The following connection options are supported after the question mark:
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//
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// connect=direct
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//
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// This option will disable the automatic replica set server
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// discovery logic, and will only use the servers provided.
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// This enables forcing the communication with a specific
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// server or set of servers (even if they are slaves). Note
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// that to talk to a slave you'll need to relax the consistency
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// requirements using a Monotonic or Eventual mode via SetMode.
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//
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// Relevant documentation:
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//
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// http://www.mongodb.org/display/DOCS/Connections
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//
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func Dial(url string) (session *Session, err error) {
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session, err = DialWithTimeout(url, 10*time.Second)
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if err == nil {
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session.SetSyncTimeout(time.Minute)
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}
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return
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}
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// DialWithTimeout works like Dial, but uses timeout as the amount of time to
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// wait for a server to respond when first connecting and also on follow up
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// operations in the session. If timeout is zero, the call may block
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// forever waiting for a connection to be made.
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//
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// See SetSyncTimeout for customizing the timeout for the session.
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func DialWithTimeout(url string, timeout time.Duration) (session *Session, err error) {
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servers, auth, options, err := parseURL(url)
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if err != nil {
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return nil, err
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}
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direct := false
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for k, v := range options {
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switch k {
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case "connect":
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if v == "direct" {
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direct = true
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break
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}
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if v == "replicaSet" {
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break
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}
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fallthrough
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default:
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err = errors.New("Unsupported connection URL option: " + k + "=" + v)
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return
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}
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}
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cluster := newCluster(servers, direct)
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session = newSession(Eventual, cluster, nil, timeout)
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if auth.user != "" {
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session.urlauth = &auth
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session.auth = []authInfo{auth}
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}
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cluster.Release()
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// People get confused when we return a session that is not actually
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// established to any servers yet (e.g. what if url was wrong). So,
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// ping the server to ensure there's someone there, and abort if it
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// fails.
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if err := session.Ping(); err != nil {
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session.Close()
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return nil, err
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}
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session.SetMode(Strong, true)
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return session, nil
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}
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func isOptSep(c rune) bool {
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return c == ';' || c == '&'
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}
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func parseURL(url string) (servers []string, auth authInfo, options map[string]string, err error) {
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if strings.HasPrefix(url, "mongodb://") {
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url = url[10:]
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}
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options = make(map[string]string)
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if c := strings.Index(url, "?"); c != -1 {
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for _, pair := range strings.FieldsFunc(url[c+1:], isOptSep) {
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l := strings.SplitN(pair, "=", 2)
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if len(l) != 2 || l[0] == "" || l[1] == "" {
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err = errors.New("Connection option must be key=value: " + pair)
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return
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}
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options[l[0]] = l[1]
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}
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url = url[:c]
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}
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if c := strings.Index(url, "@"); c != -1 {
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pair := strings.SplitN(url[:c], ":", 2)
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if len(pair) != 2 || pair[0] == "" {
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err = errors.New("Credentials must be provided as user:pass@host")
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return
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}
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auth.user = pair[0]
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auth.pass = pair[1]
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url = url[c+1:]
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auth.db = "admin"
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}
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if c := strings.Index(url, "/"); c != -1 {
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if c != len(url)-1 {
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auth.db = url[c+1:]
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}
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url = url[:c]
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}
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if auth.user == "" {
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if auth.db != "" {
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err = errors.New("Database name only makes sense with credentials")
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return
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}
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} else if auth.db == "" {
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auth.db = "admin"
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}
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servers = strings.Split(url, ",")
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// XXX This is untested. The test suite doesn't use the standard port.
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for i, server := range servers {
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p := strings.LastIndexAny(server, "]:")
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if p == -1 || server[p] != ':' {
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servers[i] = server + ":27017"
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}
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}
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return
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}
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func newSession(consistency mode, cluster *mongoCluster, socket *mongoSocket, syncTimeout time.Duration) (session *Session) {
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cluster.Acquire()
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session = &Session{cluster_: cluster, syncTimeout: syncTimeout}
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debugf("New session %p on cluster %p", session, cluster)
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session.SetMode(consistency, true)
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session.SetSafe(&Safe{})
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session.setSocket(socket)
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session.queryConfig.prefetch = defaultPrefetch
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runtime.SetFinalizer(session, finalizeSession)
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return session
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}
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func copySession(session *Session, keepAuth bool) (s *Session) {
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cluster := session.cluster()
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cluster.Acquire()
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if session.socket != nil {
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session.socket.Acquire()
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}
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var auth []authInfo
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if keepAuth {
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auth = make([]authInfo, len(session.auth))
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copy(auth, session.auth)
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} else if session.urlauth != nil {
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auth = []authInfo{*session.urlauth}
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}
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// Copy everything but the mutex.
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s = &Session{
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cluster_: session.cluster_,
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socket: session.socket,
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socketIsMaster: session.socketIsMaster,
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slaveOk: session.slaveOk,
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consistency: session.consistency,
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queryConfig: session.queryConfig,
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safeOp: session.safeOp,
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syncTimeout: session.syncTimeout,
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urlauth: session.urlauth,
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auth: auth,
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}
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debugf("New session %p on cluster %p (copy from %p)", s, cluster, session)
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runtime.SetFinalizer(s, finalizeSession)
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return s
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}
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func finalizeSession(session *Session) {
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session.Close()
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}
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// LiveServers returns a list of server addresses which are
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// currently known to be alive.
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func (s *Session) LiveServers() (addrs []string) {
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s.m.RLock()
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addrs = s.cluster().LiveServers()
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s.m.RUnlock()
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return addrs
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}
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// DB returns a value representing the named database.
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// Creating this value is a very lightweight operation, and involves
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// no network communication.
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func (s *Session) DB(name string) *Database {
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return &Database{s, name}
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}
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// C returns a value representing the named collection.
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// Creating this object is a very lightweight operation, and involves
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// no network communication.
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func (db *Database) C(name string) *Collection {
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return &Collection{db, name, db.Name + "." + name}
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}
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// With returns a copy of db that uses session s.
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func (db *Database) With(s *Session) *Database {
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newdb := *db
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newdb.Session = s
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return &newdb
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}
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// With returns a copy of c that uses session s.
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func (c *Collection) With(s *Session) *Collection {
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newdb := *c.Database
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newdb.Session = s
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newc := *c
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newc.Database = &newdb
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return &newc
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}
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// GridFS returns a GridFS value representing collections in db that
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// follow the standard GridFS specification.
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// The provided prefix (sometimes known as root) will determine which
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// collections to use, and is usually set to "fs" when there is a
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// single GridFS in the database.
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//
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// See the GridFS Create, Open, and OpenId methods for more details.
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//
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// Relevant documentation:
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//
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// http://www.mongodb.org/display/DOCS/GridFS
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// http://www.mongodb.org/display/DOCS/GridFS+Tools
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// http://www.mongodb.org/display/DOCS/GridFS+Specification
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//
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func (db *Database) GridFS(prefix string) *GridFS {
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return newGridFS(db, prefix)
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}
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// Run issues the provided command against the database and unmarshals
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// its result in the respective argument. The cmd argument may be either
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// a string with the command name itself, in which case an empty document of
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// the form bson.M{cmd: 1} will be used, or it may be a full command document.
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//
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// Note that MongoDB considers the first marshalled key as the command
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// name, so when providing a command with options, it's important to
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// use an ordering-preserving document, such as a struct value or an
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// instance of bson.D. For instance:
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//
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// db.Run(bson.D{{"create", "mycollection"}, {"size", 1024}})
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//
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// For privilleged commands typically run against the "admin" database, see
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// the Run method in the Session type.
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//
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// Relevant documentation:
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//
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// http://www.mongodb.org/display/DOCS/Commands
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// http://www.mongodb.org/display/DOCS/List+of+Database+CommandSkips
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//
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func (db *Database) Run(cmd interface{}, result interface{}) error {
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if name, ok := cmd.(string); ok {
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cmd = bson.D{{name, 1}}
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}
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return db.C("$cmd").Find(cmd).One(result)
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}
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// Login authenticates against MongoDB with the provided credentials. The
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// authentication is valid for the whole session and will stay valid until
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// Logout is explicitly called for the same database, or the session is
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// closed.
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//
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// Concurrent Login calls will work correctly.
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func (db *Database) Login(user, pass string) (err error) {
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session := db.Session
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dbname := db.Name
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socket, err := session.acquireSocket(false)
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if err != nil {
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return err
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}
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defer socket.Release()
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err = socket.Login(dbname, user, pass)
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if err != nil {
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return err
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}
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session.m.Lock()
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defer session.m.Unlock()
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for _, a := range session.auth {
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if a.db == dbname {
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a.user = user
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a.pass = pass
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return nil
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}
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}
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session.auth = append(session.auth, authInfo{dbname, user, pass})
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return nil
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}
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// Logout removes any established authentication credentials for the database.
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func (db *Database) Logout() {
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session := db.Session
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dbname := db.Name
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session.m.Lock()
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found := false
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for i, a := range session.auth {
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if a.db == dbname {
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copy(session.auth[i:], session.auth[i+1:])
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session.auth = session.auth[:len(session.auth)-1]
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found = true
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break
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}
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}
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if found && session.socket != nil {
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session.socket.Logout(dbname)
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}
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session.m.Unlock()
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}
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// LogoutAll removes all established authentication credentials for the session.
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func (s *Session) LogoutAll() {
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s.m.Lock()
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for _, a := range s.auth {
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s.socket.Logout(a.db)
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}
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s.auth = s.auth[0:0]
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s.m.Unlock()
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}
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// AddUser creates or updates the authentication credentials of user within
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// the database.
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func (db *Database) AddUser(user, pass string, readOnly bool) error {
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psum := md5.New()
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psum.Write([]byte(user + ":mongo:" + pass))
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digest := hex.EncodeToString(psum.Sum(nil))
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c := db.C("system.users")
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_, err := c.Upsert(bson.M{"user": user}, bson.M{"$set": bson.M{"user": user, "pwd": digest, "readOnly": readOnly}})
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return err
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}
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// RemoveUser removes the authentication credentials of user from the database.
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func (db *Database) RemoveUser(user string) error {
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c := db.C("system.users")
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return c.Remove(bson.M{"user": user})
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}
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type indexSpec struct {
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Name, NS string
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Key bson.D
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Unique bool ",omitempty"
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DropDups bool "dropDups,omitempty"
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Background bool ",omitempty"
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Sparse bool ",omitempty"
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Bits, Min, Max int ",omitempty"
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}
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type Index struct {
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Key []string // Index key fields; prefix name with dash (-) for descending order
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Unique bool // Prevent two documents from having the same index key
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DropDups bool // Drop documents with the same index key as a previously indexed one
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Background bool // Build index in background and return immediately
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Sparse bool // Only index documents containing the Key fields
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Name string // Index name, computed by EnsureIndex
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Bits, Min, Max int // Properties for spatial indexes
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}
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|
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func parseIndexKey(key []string) (name string, realKey bson.D, err error) {
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var order interface{}
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for _, field := range key {
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if name != "" {
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name += "_"
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}
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if field != "" {
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switch field[0] {
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case '@':
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order = "2d"
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field = field[1:]
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name += field + "_" // Why don't they put 2d here?
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case '-':
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order = -1
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field = field[1:]
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name += field + "_-1"
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case '+':
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field = field[1:]
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fallthrough
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default:
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order = 1
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name += field + "_1"
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}
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|
}
|
|
if field == "" {
|
|
return "", nil, errors.New("Invalid index key: empty field name")
|
|
}
|
|
realKey = append(realKey, bson.DocElem{field, order})
|
|
}
|
|
if name == "" {
|
|
return "", nil, errors.New("Invalid index key: no fields provided")
|
|
}
|
|
return
|
|
}
|
|
|
|
// EnsureIndexKey ensures an index with the given key exists, creating it
|
|
// if necessary.
|
|
//
|
|
// This example:
|
|
//
|
|
// err := collection.EnsureIndexKey("a", "b")
|
|
//
|
|
// Is equivalent to:
|
|
//
|
|
// err := collection.EnsureIndex(mgo.Index{Key: []string{"a", "b"}})
|
|
//
|
|
// See the EnsureIndex method for more details.
|
|
func (c *Collection) EnsureIndexKey(key ...string) error {
|
|
return c.EnsureIndex(Index{Key: key})
|
|
}
|
|
|
|
// EnsureIndex ensures an index with the given key exists, creating it with
|
|
// the provided parameters if necessary.
|
|
//
|
|
// Once EnsureIndex returns successfully, following requests for the same index
|
|
// will not contact the server unless Collection.DropIndex is used to drop the
|
|
// same index, or Session.ResetIndexCache is called.
|
|
//
|
|
// For example:
|
|
//
|
|
// index := Index{
|
|
// Key: []string{"lastname", "firstname"},
|
|
// Unique: true,
|
|
// DropDups: true,
|
|
// Background: true, // See notes.
|
|
// Sparse: true,
|
|
// }
|
|
// err := collection.EnsureIndex(index)
|
|
//
|
|
// The Key value determines which fields compose the index. The index ordering
|
|
// will be ascending by default. To obtain an index with a descending order,
|
|
// the field name should be prefixed by a dash (e.g. []string{"-time"}).
|
|
//
|
|
// If Unique is true, the index must necessarily contain only a single
|
|
// document per Key. With DropDups set to true, documents with the same key
|
|
// as a previously indexed one will be dropped rather than an error returned.
|
|
//
|
|
// If Background is true, other connections will be allowed to proceed using
|
|
// the collection without the index while it's being built. Note that the
|
|
// session executing EnsureIndex will be blocked for as long as it takes for
|
|
// the index to be built.
|
|
//
|
|
// If Sparse is true, only documents containing the provided Key fields will be
|
|
// included in the index. When using a sparse index for sorting, only indexed
|
|
// documents will be returned.
|
|
//
|
|
// Spatial indexes are also supported through that API. Here is an example:
|
|
//
|
|
// index := Index{
|
|
// Key: []string{"@loc"},
|
|
// Bits: 26,
|
|
// }
|
|
// err := collection.EnsureIndex(index)
|
|
//
|
|
// The "@" prefix in the field name will request the creation of a "2d" index
|
|
// for the given field.
|
|
//
|
|
// The 2D index bounds may be changed using the Min and Max attributes of the
|
|
// Index value. The default bound setting of (-180, 180) is suitable for
|
|
// latitude/longitude pairs.
|
|
//
|
|
// The Bits parameter sets the precision of the 2D geohash values. If not
|
|
// provided, 26 bits are used, which is roughly equivalent to 1 foot of
|
|
// precision for the default (-180, 180) index bounds.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Indexes
|
|
// http://www.mongodb.org/display/DOCS/Indexing+Advice+and+FAQ
|
|
// http://www.mongodb.org/display/DOCS/Indexing+as+a+Background+Operation
|
|
// http://www.mongodb.org/display/DOCS/Geospatial+Indexing
|
|
// http://www.mongodb.org/display/DOCS/Multikeys
|
|
//
|
|
func (c *Collection) EnsureIndex(index Index) error {
|
|
name, realKey, err := parseIndexKey(index.Key)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
session := c.Database.Session
|
|
cacheKey := c.FullName + "\x00" + name
|
|
if session.cluster().HasCachedIndex(cacheKey) {
|
|
return nil
|
|
}
|
|
|
|
spec := indexSpec{
|
|
Name: name,
|
|
NS: c.FullName,
|
|
Key: realKey,
|
|
Unique: index.Unique,
|
|
DropDups: index.DropDups,
|
|
Background: index.Background,
|
|
Sparse: index.Sparse,
|
|
Bits: index.Bits,
|
|
Min: index.Min,
|
|
Max: index.Max,
|
|
}
|
|
|
|
session = session.Clone()
|
|
defer session.Close()
|
|
session.SetMode(Strong, false)
|
|
session.EnsureSafe(&Safe{})
|
|
|
|
db := c.Database.With(session)
|
|
err = db.C("system.indexes").Insert(&spec)
|
|
if err == nil {
|
|
session.cluster().CacheIndex(cacheKey, true)
|
|
}
|
|
session.Close()
|
|
return err
|
|
}
|
|
|
|
// DropIndex removes the index with key from the collection.
|
|
//
|
|
// The key value determines which fields compose the index. The index ordering
|
|
// will be ascending by default. To obtain an index with a descending order,
|
|
// the field name should be prefixed by a dash (e.g. []string{"-time"}).
|
|
//
|
|
// For example:
|
|
//
|
|
// err := collection.DropIndex("lastname", "firstname")
|
|
//
|
|
// See the EnsureIndex method for more details on indexes.
|
|
func (c *Collection) DropIndex(key ...string) error {
|
|
name, _, err := parseIndexKey(key)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
session := c.Database.Session
|
|
cacheKey := c.FullName + "\x00" + name
|
|
session.cluster().CacheIndex(cacheKey, false)
|
|
|
|
session = session.Clone()
|
|
defer session.Close()
|
|
session.SetMode(Strong, false)
|
|
|
|
db := c.Database.With(session)
|
|
result := struct {
|
|
ErrMsg string
|
|
Ok bool
|
|
}{}
|
|
err = db.Run(bson.D{{"dropIndexes", c.Name}, {"index", name}}, &result)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if !result.Ok {
|
|
return errors.New(result.ErrMsg)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Indexes returns a list of all indexes for the collection.
|
|
//
|
|
// For example, this snippet would drop all available indexes:
|
|
//
|
|
// indexes, err := collection.Indexes()
|
|
// if err != nil {
|
|
// panic(err)
|
|
// }
|
|
// for _, index := range indexes {
|
|
// err = collection.DropIndex(index.Key...)
|
|
// if err != nil {
|
|
// panic(err)
|
|
// }
|
|
// }
|
|
//
|
|
// See the EnsureIndex method for more details on indexes.
|
|
func (c *Collection) Indexes() (indexes []Index, err error) {
|
|
query := c.Database.C("system.indexes").Find(bson.M{"ns": c.FullName})
|
|
iter := query.Sort("name").Iter()
|
|
for {
|
|
var spec indexSpec
|
|
if !iter.Next(&spec) {
|
|
break
|
|
}
|
|
index := Index{
|
|
Name: spec.Name,
|
|
Key: simpleIndexKey(spec.Key),
|
|
Unique: spec.Unique,
|
|
DropDups: spec.DropDups,
|
|
Background: spec.Background,
|
|
Sparse: spec.Sparse,
|
|
}
|
|
indexes = append(indexes, index)
|
|
}
|
|
err = iter.Err()
|
|
return
|
|
}
|
|
|
|
func simpleIndexKey(realKey bson.D) (key []string) {
|
|
for i := range realKey {
|
|
field := realKey[i].Name
|
|
i, _ := realKey[i].Value.(int)
|
|
if i == 1 {
|
|
key = append(key, field)
|
|
continue
|
|
}
|
|
if i == -1 {
|
|
key = append(key, "-"+field)
|
|
continue
|
|
}
|
|
s, _ := realKey[i].Value.(string)
|
|
if s == "2d" {
|
|
key = append(key, "@"+field)
|
|
continue
|
|
}
|
|
panic("Got unknown index key type for field " + field)
|
|
}
|
|
return
|
|
}
|
|
|
|
// ResetIndexCache() clears the cache of previously ensured indexes.
|
|
// Following requests to EnsureIndex will contact the server.
|
|
func (s *Session) ResetIndexCache() {
|
|
s.cluster().ResetIndexCache()
|
|
}
|
|
|
|
// New creates a new session with the same parameters as the original
|
|
// session, including consistency, batch size, prefetching, safety mode,
|
|
// etc. The returned session will use sockets from the poll, so there's
|
|
// a chance that writes just performed in another session may not yet
|
|
// be visible.
|
|
//
|
|
// Login information from the original session will not be copied over
|
|
// into the new session unless it was provided through the initial URL
|
|
// for the Dial function.
|
|
//
|
|
// See the Copy and Clone methods.
|
|
//
|
|
func (s *Session) New() *Session {
|
|
s.m.Lock()
|
|
scopy := copySession(s, false)
|
|
s.m.Unlock()
|
|
scopy.Refresh()
|
|
return scopy
|
|
}
|
|
|
|
// Copy works just like New, but preserves the exact authentication
|
|
// information from the original session.
|
|
func (s *Session) Copy() *Session {
|
|
s.m.Lock()
|
|
scopy := copySession(s, true)
|
|
s.m.Unlock()
|
|
scopy.Refresh()
|
|
return scopy
|
|
}
|
|
|
|
// Clone works just like Copy, but also reuses the same socket as the original
|
|
// session, in case it had already reserved one due to its consistency
|
|
// guarantees. This behavior ensures that writes performed in the old session
|
|
// are necessarily observed when using the new session, as long as it was a
|
|
// strong or monotonic session. That said, it also means that long operations
|
|
// may cause other goroutines using the original session to wait.
|
|
func (s *Session) Clone() *Session {
|
|
s.m.Lock()
|
|
scopy := copySession(s, true)
|
|
s.m.Unlock()
|
|
return scopy
|
|
}
|
|
|
|
// Close terminates the session. It's a runtime error to use a session
|
|
// after it has been closed.
|
|
func (s *Session) Close() {
|
|
s.m.Lock()
|
|
if s.cluster_ != nil {
|
|
debugf("Closing session %p", s)
|
|
s.setSocket(nil)
|
|
s.cluster_.Release()
|
|
s.cluster_ = nil
|
|
}
|
|
s.m.Unlock()
|
|
}
|
|
|
|
func (s *Session) cluster() *mongoCluster {
|
|
if s.cluster_ == nil {
|
|
panic("Session already closed")
|
|
}
|
|
return s.cluster_
|
|
}
|
|
|
|
// Refresh puts back any reserved sockets in use and restarts the consistency
|
|
// guarantees according to the current consistency setting for the session.
|
|
func (s *Session) Refresh() {
|
|
s.m.Lock()
|
|
s.slaveOk = s.consistency != Strong
|
|
s.setSocket(nil)
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// SetMode changes the consistency mode for the session.
|
|
//
|
|
// In the Strong consistency mode reads and writes will always be made to
|
|
// the master server using a unique connection so that reads and writes are
|
|
// fully consistent, ordered, and observing the most up-to-date data.
|
|
// This offers the least benefits in terms of distributing load, but the
|
|
// most guarantees. See also Monotonic and Eventual.
|
|
//
|
|
// In the Monotonic consistency mode reads may not be entirely up-to-date,
|
|
// but they will always see the history of changes moving forward, the data
|
|
// read will be consistent across sequential queries in the same session,
|
|
// and modifications made within the session will be observed in following
|
|
// queries (read-your-writes).
|
|
//
|
|
// In practice, the Monotonic mode is obtained by performing initial reads
|
|
// against a unique connection to an arbitrary slave, if one is available,
|
|
// and once the first write happens, the session connection is switched over
|
|
// to the master server. This manages to distribute some of the reading
|
|
// load with slaves, while maintaining some useful guarantees.
|
|
//
|
|
// In the Eventual consistency mode reads will be made to any slave in the
|
|
// cluster, if one is available, and sequential reads will not necessarily
|
|
// be made with the same connection. This means that data may be observed
|
|
// out of order. Writes will of course be issued to the master, but
|
|
// independent writes in the same Eventual session may also be made with
|
|
// independent connections, so there are also no guarantees in terms of
|
|
// write ordering (no read-your-writes guarantees either).
|
|
//
|
|
// The Eventual mode is the fastest and most resource-friendly, but is
|
|
// also the one offering the least guarantees about ordering of the data
|
|
// read and written.
|
|
//
|
|
// If refresh is true, in addition to ensuring the session is in the given
|
|
// consistency mode, the consistency guarantees will also be reset (e.g.
|
|
// a Monotonic session will be allowed to read from slaves again). This is
|
|
// equivalent to calling the Refresh function.
|
|
//
|
|
// Shifting between Monotonic and Strong modes will keep a previously
|
|
// reserved connection for the session unless refresh is true or the
|
|
// connection is unsuitable (to a slave server in a Strong session).
|
|
func (s *Session) SetMode(consistency mode, refresh bool) {
|
|
s.m.Lock()
|
|
debugf("Session %p: setting mode %d with refresh=%v (socket=%p)", s, consistency, refresh, s.socket)
|
|
s.consistency = consistency
|
|
if refresh {
|
|
s.slaveOk = s.consistency != Strong
|
|
s.setSocket(nil)
|
|
} else if s.consistency == Strong {
|
|
s.slaveOk = false
|
|
} else if s.socket == nil {
|
|
s.slaveOk = true
|
|
}
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// Mode returns the current consistency mode for the session.
|
|
func (s *Session) Mode() mode {
|
|
s.m.RLock()
|
|
mode := s.consistency
|
|
s.m.RUnlock()
|
|
return mode
|
|
}
|
|
|
|
// SetSyncTimeout sets the amount of time an operation with this session
|
|
// will wait before returning an error in case a connection to a usable
|
|
// server can't be established. Set it to zero to wait forever. The
|
|
// default value is 7 seconds.
|
|
func (s *Session) SetSyncTimeout(d time.Duration) {
|
|
s.m.Lock()
|
|
s.syncTimeout = d
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// SetBatch sets the default batch size used when fetching documents from the
|
|
// database. It's possible to change this setting on a per-query basis as
|
|
// well, using the Query.Batch method.
|
|
//
|
|
// The default batch size is defined by the database itself. As of this
|
|
// writing, MongoDB will use an initial size of min(100 docs, 4MB) on the
|
|
// first batch, and 4MB on remaining ones.
|
|
func (s *Session) SetBatch(n int) {
|
|
s.m.Lock()
|
|
s.queryConfig.op.limit = int32(n)
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// SetPrefetch sets the default point at which the next batch of results will be
|
|
// requested. When there are p*batch_size remaining documents cached in an
|
|
// Iter, the next batch will be requested in background. For instance, when
|
|
// using this:
|
|
//
|
|
// session.SetBatch(200)
|
|
// session.SetPrefetch(0.25)
|
|
//
|
|
// and there are only 50 documents cached in the Iter to be processed, the
|
|
// next batch of 200 will be requested. It's possible to change this setting on
|
|
// a per-query basis as well, using the Prefetch method of Query.
|
|
//
|
|
// The default prefetch value is 0.25.
|
|
func (s *Session) SetPrefetch(p float64) {
|
|
s.m.Lock()
|
|
s.queryConfig.prefetch = p
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// See SetSafe for details on the Safe type.
|
|
type Safe struct {
|
|
W int // Min # of servers to ack before success
|
|
WMode string // Write mode for MongoDB 2.0+ (e.g. "majority")
|
|
WTimeout int // Milliseconds to wait for W before timing out
|
|
FSync bool // Should servers sync to disk before returning success
|
|
J bool // Wait for next group commit if journaling; no effect otherwise
|
|
}
|
|
|
|
// Safe returns the current safety mode for the session.
|
|
func (s *Session) Safe() (safe *Safe) {
|
|
s.m.Lock()
|
|
defer s.m.Unlock()
|
|
if s.safeOp != nil {
|
|
cmd := s.safeOp.query.(*getLastError)
|
|
safe = &Safe{WTimeout: cmd.WTimeout, FSync: cmd.FSync, J: cmd.J}
|
|
switch w := cmd.W.(type) {
|
|
case string:
|
|
safe.WMode = w
|
|
case int:
|
|
safe.W = w
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
// SetSafe changes the session safety mode.
|
|
//
|
|
// If the safe parameter is nil, the session is put in unsafe mode, and writes
|
|
// become fire-and-forget, without error checking. The unsafe mode is faster
|
|
// since operations won't hold on waiting for a confirmation.
|
|
//
|
|
// If the safe parameter is not nil, any changing query (insert, update, ...)
|
|
// will be followed by a getLastError command with the specified parameters,
|
|
// to ensure the request was correctly processed.
|
|
//
|
|
// The safe.W parameter determines how many servers should confirm a write
|
|
// before the operation is considered successful. If set to 0 or 1, the
|
|
// command will return as soon as the master is done with the request.
|
|
// If safe.WTimeout is greater than zero, it determines how many milliseconds
|
|
// to wait for the safe.W servers to respond before returning an error.
|
|
//
|
|
// Starting with MongoDB 2.0.0 the safe.WMode parameter can be used instead
|
|
// of W to request for richer semantics. If set to "majority" the server will
|
|
// wait for a majority of members from the replica set to respond before
|
|
// returning. Custom modes may also be defined within the server to create
|
|
// very detailed placement schemas. See the data awareness documentation in
|
|
// the links below for more details (note that MongoDB internally reuses the
|
|
// "w" field name for WMode).
|
|
//
|
|
// If safe.FSync is true and journaling is disabled, the servers will be
|
|
// forced to sync all files to disk immediately before returning. If the
|
|
// same option is true but journaling is enabled, the server will instead
|
|
// await for the next group commit before returning.
|
|
//
|
|
// Since MongoDB 2.0.0, the safe.J option can also be used instead of FSync
|
|
// to force the server to wait for a group commit in case journaling is
|
|
// enabled. The option has no effect if the server has journaling disabled.
|
|
//
|
|
// For example, the following statement will make the session check for
|
|
// errors, without imposing further constraints:
|
|
//
|
|
// session.SetSafe(&mgo.Safe{})
|
|
//
|
|
// The following statement will force the server to wait for a majority of
|
|
// members of a replica set to return (MongoDB 2.0+ only):
|
|
//
|
|
// session.SetSafe(&mgo.Safe{WMode: "majority"})
|
|
//
|
|
// The following statement, on the other hand, ensures that at least two
|
|
// servers have flushed the change to disk before confirming the success
|
|
// of operations:
|
|
//
|
|
// session.EnsureSafe(&mgo.Safe{W: 2, FSync: true})
|
|
//
|
|
// The following statement, on the other hand, disables the verification
|
|
// of errors entirely:
|
|
//
|
|
// session.SetSafe(nil)
|
|
//
|
|
// See also the EnsureSafe method.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/getLastError+Command
|
|
// http://www.mongodb.org/display/DOCS/Verifying+Propagation+of+Writes+with+getLastError
|
|
// http://www.mongodb.org/display/DOCS/Data+Center+Awareness
|
|
//
|
|
func (s *Session) SetSafe(safe *Safe) {
|
|
s.m.Lock()
|
|
s.safeOp = nil
|
|
s.ensureSafe(safe)
|
|
s.m.Unlock()
|
|
}
|
|
|
|
// EnsureSafe compares the provided safety parameters with the ones
|
|
// currently in use by the session and picks the most conservative
|
|
// choice for each setting.
|
|
//
|
|
// That is:
|
|
//
|
|
// - safe.WMode is always used if set.
|
|
// - safe.W is used if larger than the current W and WMode is empty.
|
|
// - safe.FSync is always used if true.
|
|
// - safe.J is used if FSync is false.
|
|
// - safe.WTimeout is used if set and smaller than the current WTimeout.
|
|
//
|
|
// For example, the following statement will ensure the session is
|
|
// at least checking for errors, without enforcing further constraints.
|
|
// If a more conservative SetSafe or EnsureSafe call was previously done,
|
|
// the following call will be ignored.
|
|
//
|
|
// session.EnsureSafe(&mgo.Safe{})
|
|
//
|
|
// See also the SetSafe method for details on what each option means.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/getLastError+Command
|
|
// http://www.mongodb.org/display/DOCS/Verifying+Propagation+of+Writes+with+getLastError
|
|
// http://www.mongodb.org/display/DOCS/Data+Center+Awareness
|
|
//
|
|
func (s *Session) EnsureSafe(safe *Safe) {
|
|
s.m.Lock()
|
|
s.ensureSafe(safe)
|
|
s.m.Unlock()
|
|
}
|
|
|
|
func (s *Session) ensureSafe(safe *Safe) {
|
|
if safe == nil {
|
|
return
|
|
}
|
|
|
|
var w interface{}
|
|
if safe.WMode != "" {
|
|
w = safe.WMode
|
|
} else if safe.W > 0 {
|
|
w = safe.W
|
|
}
|
|
|
|
var cmd getLastError
|
|
if s.safeOp == nil {
|
|
cmd = getLastError{1, w, safe.WTimeout, safe.FSync, safe.J}
|
|
} else {
|
|
// Copy. We don't want to mutate the existing query.
|
|
cmd = *(s.safeOp.query.(*getLastError))
|
|
if cmd.W == nil {
|
|
cmd.W = w
|
|
} else if safe.WMode != "" {
|
|
cmd.W = safe.WMode
|
|
} else if i, ok := cmd.W.(int); ok && safe.W > i {
|
|
cmd.W = safe.W
|
|
}
|
|
if safe.WTimeout > 0 && safe.WTimeout < cmd.WTimeout {
|
|
cmd.WTimeout = safe.WTimeout
|
|
}
|
|
if safe.FSync {
|
|
cmd.FSync = true
|
|
cmd.J = false
|
|
} else if safe.J && !cmd.FSync {
|
|
cmd.J = true
|
|
}
|
|
}
|
|
s.safeOp = &queryOp{
|
|
query: &cmd,
|
|
collection: "admin.$cmd",
|
|
limit: -1,
|
|
}
|
|
}
|
|
|
|
// Run issues the provided command against the "admin" database and
|
|
// and unmarshals its result in the respective argument. The cmd
|
|
// argument may be either a string with the command name itself, in
|
|
// which case an empty document of the form bson.M{cmd: 1} will be used,
|
|
// or it may be a full command document.
|
|
//
|
|
// Note that MongoDB considers the first marshalled key as the command
|
|
// name, so when providing a command with options, it's important to
|
|
// use an ordering-preserving document, such as a struct value or an
|
|
// instance of bson.D. For instance:
|
|
//
|
|
// db.Run(bson.D{{"create", "mycollection"}, {"size", 1024}})
|
|
//
|
|
// For commands against arbitrary databases, see the Run method in
|
|
// the Database type.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Commands
|
|
// http://www.mongodb.org/display/DOCS/List+of+Database+CommandSkips
|
|
//
|
|
func (s *Session) Run(cmd interface{}, result interface{}) error {
|
|
return s.DB("admin").Run(cmd, result)
|
|
}
|
|
|
|
// Ping runs a trivial ping command just to get in touch with the server.
|
|
func (s *Session) Ping() error {
|
|
return s.Run("ping", nil)
|
|
}
|
|
|
|
// Fsync flushes in-memory writes to disk on the server the session
|
|
// is established with. If async is true, the call returns immediately,
|
|
// otherwise it returns after the flush has been made.
|
|
func (s *Session) Fsync(async bool) error {
|
|
return s.Run(bson.D{{"fsync", 1}, {"async", async}}, nil)
|
|
}
|
|
|
|
// FsyncLock locks all writes in the specific server the session is
|
|
// established with and returns. Any writes attempted to the server
|
|
// after it is successfully locked will block until FsyncUnlock is
|
|
// called for the same server.
|
|
//
|
|
// This method works on slaves as well, preventing the oplog from being
|
|
// flushed while the server is locked, but since only the server
|
|
// connected to is locked, for locking specific slaves it may be
|
|
// necessary to establish a connection directly to the slave (see
|
|
// Dial's connect=direct option).
|
|
//
|
|
// As an important caveat, note that once a write is attempted and
|
|
// blocks, follow up reads will block as well due to the way the
|
|
// lock is internally implemented in the server. More details at:
|
|
//
|
|
// https://jira.mongodb.org/browse/SERVER-4243
|
|
//
|
|
// FsyncLock is often used for performing consistent backups of
|
|
// the database files on disk.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/fsync+Command
|
|
// http://www.mongodb.org/display/DOCS/Backups
|
|
//
|
|
func (s *Session) FsyncLock() error {
|
|
return s.Run(bson.D{{"fsync", 1}, {"lock", true}}, nil)
|
|
}
|
|
|
|
// FsyncUnlock releases the server for writes. See FsyncLock for details.
|
|
func (s *Session) FsyncUnlock() error {
|
|
return s.DB("admin").C("$cmd.sys.unlock").Find(nil).One(nil) // WTF?
|
|
}
|
|
|
|
// Find prepares a query using the provided document. The document may be a
|
|
// map or a struct value capable of being marshalled with bson. The map
|
|
// may be a generic one using interface{} for its key and/or values, such as
|
|
// bson.M, or it may be a properly typed map. Providing nil as the document
|
|
// is equivalent to providing an empty document such as bson.M{}.
|
|
//
|
|
// Further details of the query may be tweaked using the resulting Query value,
|
|
// and then executed to retrieve results using methods such as One, For,
|
|
// Iter, or Tail.
|
|
//
|
|
// In case the resulting document includes a field named $err or errmsg, which
|
|
// are standard ways for MongoDB to return query errors, the returned err will
|
|
// be set to a *QueryError value including the Err message and the Code. In
|
|
// those cases, the result argument is still unmarshalled into with the
|
|
// received document so that any other custom values may be obtained if
|
|
// desired.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Querying
|
|
// http://www.mongodb.org/display/DOCS/Advanced+Queries
|
|
//
|
|
func (c *Collection) Find(query interface{}) *Query {
|
|
session := c.Database.Session
|
|
session.m.RLock()
|
|
q := &Query{session: session, query: session.queryConfig}
|
|
session.m.RUnlock()
|
|
q.op.query = query
|
|
q.op.collection = c.FullName
|
|
return q
|
|
}
|
|
|
|
// FindId prepares a query to find a document by its _id field.
|
|
// It is a convenience helper equivalent to:
|
|
//
|
|
// query := collection.Find(bson.M{"_id": id})
|
|
//
|
|
// See the Find method for more details.
|
|
func (c *Collection) FindId(id interface{}) *Query {
|
|
return c.Find(bson.D{{"_id", id}})
|
|
}
|
|
|
|
type LastError struct {
|
|
Err string
|
|
Code, N, Waited int
|
|
FSyncFiles int "fsyncFiles"
|
|
WTimeout bool
|
|
UpdatedExisting bool "updatedExisting"
|
|
UpsertedId interface{} "upserted"
|
|
}
|
|
|
|
func (err *LastError) Error() string {
|
|
return err.Err
|
|
}
|
|
|
|
type queryError struct {
|
|
Err string "$err"
|
|
ErrMsg string
|
|
Assertion string
|
|
Code int
|
|
AssertionCode int "assertionCode"
|
|
LastError *LastError "lastErrorObject"
|
|
}
|
|
|
|
type QueryError struct {
|
|
Code int
|
|
Message string
|
|
Assertion bool
|
|
}
|
|
|
|
func (err *QueryError) Error() string {
|
|
return err.Message
|
|
}
|
|
|
|
// Insert inserts one or more documents in the respective collection. In
|
|
// case the session is in safe mode (see the SetSafe method) and an error
|
|
// happens while inserting the provided documents, the returned error will
|
|
// be of type *LastError.
|
|
func (c *Collection) Insert(docs ...interface{}) error {
|
|
_, err := c.Database.Session.writeQuery(&insertOp{c.FullName, docs})
|
|
return err
|
|
}
|
|
|
|
// Update finds a single document matching the provided selector document
|
|
// and modifies it according to the change document.
|
|
// If the session is in safe mode (see SetSafe) a ErrNotFound error is
|
|
// returned if a document isn't found, or a value of type *LastError
|
|
// when some other error is detected.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Updating
|
|
// http://www.mongodb.org/display/DOCS/Atomic+Operations
|
|
//
|
|
func (c *Collection) Update(selector interface{}, change interface{}) error {
|
|
session := c.Database.Session
|
|
lerr, err := session.writeQuery(&updateOp{c.FullName, selector, change, 0})
|
|
if err == nil && lerr != nil && !lerr.UpdatedExisting {
|
|
return ErrNotFound
|
|
}
|
|
return err
|
|
}
|
|
|
|
// ChangeInfo holds details about the outcome of a change operation.
|
|
type ChangeInfo struct {
|
|
Updated int // Number of existing documents updated
|
|
Removed int // Number of documents removed
|
|
UpsertedId interface{} // Upserted _id field, when not explicitly provided
|
|
}
|
|
|
|
// UpdateAll finds all documents matching the provided selector document
|
|
// and modifies them according to the change document.
|
|
// If the session is in safe mode (see SetSafe) details of the executed
|
|
// operation are returned in info or an error of type *LastError when
|
|
// some problem is detected. It is not an error for the update to not be
|
|
// applied on any documents because the selector doesn't match.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Updating
|
|
// http://www.mongodb.org/display/DOCS/Atomic+Operations
|
|
//
|
|
func (c *Collection) UpdateAll(selector interface{}, change interface{}) (info *ChangeInfo, err error) {
|
|
session := c.Database.Session
|
|
lerr, err := session.writeQuery(&updateOp{c.FullName, selector, change, 2})
|
|
if err == nil && lerr != nil {
|
|
info = &ChangeInfo{Updated: lerr.N}
|
|
}
|
|
return info, err
|
|
}
|
|
|
|
// Upsert finds a single document matching the provided selector document
|
|
// and modifies it according to the change document. If no document matching
|
|
// the selector is found, the change document is applied to the selector
|
|
// document and the result is inserted in the collection.
|
|
// If the session is in safe mode (see SetSafe) details of the executed
|
|
// operation are returned in info, or an error of type *LastError when
|
|
// some problem is detected.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Updating
|
|
// http://www.mongodb.org/display/DOCS/Atomic+Operations
|
|
//
|
|
func (c *Collection) Upsert(selector interface{}, change interface{}) (info *ChangeInfo, err error) {
|
|
data, err := bson.Marshal(change)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
change = bson.Raw{0x03, data}
|
|
session := c.Database.Session
|
|
lerr, err := session.writeQuery(&updateOp{c.FullName, selector, change, 1})
|
|
if err == nil && lerr != nil {
|
|
info = &ChangeInfo{}
|
|
if lerr.UpdatedExisting {
|
|
info.Updated = lerr.N
|
|
} else {
|
|
info.UpsertedId = lerr.UpsertedId
|
|
}
|
|
}
|
|
return info, err
|
|
}
|
|
|
|
// Remove finds a single document matching the provided selector document
|
|
// and removes it from the database.
|
|
// If the session is in safe mode (see SetSafe) a ErrNotFound error is
|
|
// returned if a document isn't found, or a value of type *LastError
|
|
// when some other error is detected.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Removing
|
|
//
|
|
func (c *Collection) Remove(selector interface{}) error {
|
|
session := c.Database.Session
|
|
lerr, err := session.writeQuery(&deleteOp{c.FullName, selector, 1})
|
|
if err == nil && lerr != nil && lerr.N == 0 {
|
|
return ErrNotFound
|
|
}
|
|
return err
|
|
}
|
|
|
|
// RemoveAll finds all documents matching the provided selector document
|
|
// and removes them from the database. In case the session is in safe mode
|
|
// (see the SetSafe method) and an error happens when attempting the change,
|
|
// the returned error will be of type *LastError.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Removing
|
|
//
|
|
func (c *Collection) RemoveAll(selector interface{}) (info *ChangeInfo, err error) {
|
|
session := c.Database.Session
|
|
lerr, err := session.writeQuery(&deleteOp{c.FullName, selector, 0})
|
|
if err == nil && lerr != nil {
|
|
info = &ChangeInfo{Removed: lerr.N}
|
|
}
|
|
return info, err
|
|
}
|
|
|
|
// DropDatabase removes the entire database including all of its collections.
|
|
func (db *Database) DropDatabase() error {
|
|
return db.Run(bson.D{{"dropDatabase", 1}}, nil)
|
|
}
|
|
|
|
// DropCollection removes the entire collection including all of its documents.
|
|
func (c *Collection) DropCollection() error {
|
|
return c.Database.Run(bson.D{{"drop", c.Name}}, nil)
|
|
}
|
|
|
|
// The CollectionInfo type holds metadata about a collection.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/createCollection+Command
|
|
// http://www.mongodb.org/display/DOCS/Capped+Collections
|
|
//
|
|
type CollectionInfo struct {
|
|
// DisableIdIndex prevents the automatic creation of the index
|
|
// on the _id field for the collection.
|
|
DisableIdIndex bool
|
|
|
|
// ForceIdIndex enforces the automatic creation of the index
|
|
// on the _id field for the collection. Capped collections,
|
|
// for example, do not have such an index by default.
|
|
ForceIdIndex bool
|
|
|
|
// If Capped is true new documents will replace old ones when
|
|
// the collection is full. MaxBytes must necessarily be set
|
|
// to define the size when the collection wraps around.
|
|
// MaxDocs optionally defines the number of documents when it
|
|
// wraps, but MaxBytes still needs to be set.
|
|
Capped bool
|
|
MaxBytes int
|
|
MaxDocs int
|
|
}
|
|
|
|
// Create explicitly creates the c collection with details of info.
|
|
// MongoDB creates collections automatically on use, so this method
|
|
// is only necessary when creating collection with non-default
|
|
// characteristics, such as capped collections.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/createCollection+Command
|
|
// http://www.mongodb.org/display/DOCS/Capped+Collections
|
|
//
|
|
func (c *Collection) Create(info *CollectionInfo) error {
|
|
cmd := make(bson.D, 0, 4)
|
|
cmd = append(cmd, bson.DocElem{"create", c.Name})
|
|
if info.Capped {
|
|
if info.MaxBytes < 1 {
|
|
return fmt.Errorf("Collection.Create: with Capped, MaxBytes must also be set")
|
|
}
|
|
cmd = append(cmd, bson.DocElem{"capped", true})
|
|
cmd = append(cmd, bson.DocElem{"size", info.MaxBytes})
|
|
if info.MaxDocs > 0 {
|
|
cmd = append(cmd, bson.DocElem{"max", info.MaxDocs})
|
|
}
|
|
}
|
|
if info.DisableIdIndex {
|
|
cmd = append(cmd, bson.DocElem{"autoIndexId", false})
|
|
}
|
|
if info.ForceIdIndex {
|
|
cmd = append(cmd, bson.DocElem{"autoIndexId", true})
|
|
}
|
|
return c.Database.Run(cmd, nil)
|
|
}
|
|
|
|
// Batch sets the batch size used when fetching documents from the database.
|
|
// It's possible to change this setting on a per-session basis as well, using
|
|
// the Batch method of Session.
|
|
//
|
|
// The default batch size is defined by the database itself. As of this
|
|
// writing, MongoDB will use an initial size of min(100 docs, 4MB) on the
|
|
// first batch, and 4MB on remaining ones.
|
|
func (q *Query) Batch(n int) *Query {
|
|
q.m.Lock()
|
|
q.op.limit = int32(n)
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
// Prefetch sets the point at which the next batch of results will be requested.
|
|
// When there are p*batch_size remaining documents cached in an Iter, the next
|
|
// batch will be requested in background. For instance, when using this:
|
|
//
|
|
// query.Batch(200).Prefetch(0.25)
|
|
//
|
|
// and there are only 50 documents cached in the Iter to be processed, the
|
|
// next batch of 200 will be requested. It's possible to change this setting on
|
|
// a per-session basis as well, using the SetPrefetch method of Session.
|
|
//
|
|
// The default prefetch value is 0.25.
|
|
func (q *Query) Prefetch(p float64) *Query {
|
|
q.m.Lock()
|
|
q.prefetch = p
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
// Skip skips over the n initial documents from the query results. Note that
|
|
// this only makes sense with capped collections where documents are naturally
|
|
// ordered by insertion time, or with sorted results.
|
|
func (q *Query) Skip(n int) *Query {
|
|
q.m.Lock()
|
|
q.op.skip = int32(n)
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
// Limit restricts the maximum number of documents retrieved to n, and also
|
|
// changes the batch size to the same value. Once n documents have been
|
|
// returned by Next, the following call will return ErrNotFound.
|
|
func (q *Query) Limit(n int) *Query {
|
|
q.m.Lock()
|
|
switch {
|
|
case n == 1:
|
|
q.limit = 1
|
|
q.op.limit = -1
|
|
case n == math.MinInt32: // -MinInt32 == -MinInt32
|
|
q.limit = math.MaxInt32
|
|
q.op.limit = math.MinInt32 + 1
|
|
case n < 0:
|
|
q.limit = int32(-n)
|
|
q.op.limit = int32(n)
|
|
default:
|
|
q.limit = int32(n)
|
|
q.op.limit = int32(n)
|
|
}
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
// Select enables selecting which fields should be retrieved for the results
|
|
// found. For example, the following query would only retrieve the name field:
|
|
//
|
|
// err := collection.Find(nil).Select(bson.M{"name": 1}).One(&result)
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Retrieving+a+Subset+of+Fields
|
|
//
|
|
func (q *Query) Select(selector interface{}) *Query {
|
|
q.m.Lock()
|
|
q.op.selector = selector
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
type queryWrapper struct {
|
|
Query interface{} "$query"
|
|
OrderBy interface{} "$orderby,omitempty"
|
|
Hint interface{} "$hint,omitempty"
|
|
Explain bool "$explain,omitempty"
|
|
Snapshot bool "$snapshot,omitempty"
|
|
}
|
|
|
|
func (q *Query) wrap() *queryWrapper {
|
|
w, ok := q.op.query.(*queryWrapper)
|
|
if !ok {
|
|
if q.op.query == nil {
|
|
var empty bson.D
|
|
w = &queryWrapper{Query: empty}
|
|
} else {
|
|
w = &queryWrapper{Query: q.op.query}
|
|
}
|
|
q.op.query = w
|
|
}
|
|
return w
|
|
}
|
|
|
|
// Sort asks the database to order returned documents according to the
|
|
// provided field names. A field name may be prefixed by - (minus) for
|
|
// it to be sorted in reverse order.
|
|
//
|
|
// For example:
|
|
//
|
|
// query1 := collection.Find(nil).Sort("firstname", "lastname")
|
|
// query2 := collection.Find(nil).Sort("-age")
|
|
// query3 := collection.Find(nil).Sort("$natural")
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Sorting+and+Natural+Order
|
|
//
|
|
func (q *Query) Sort(fields ...string) *Query {
|
|
q.m.Lock()
|
|
w := q.wrap()
|
|
var order bson.D
|
|
for _, field := range fields {
|
|
n := 1
|
|
if field != "" {
|
|
switch field[0] {
|
|
case '+':
|
|
field = field[1:]
|
|
case '-':
|
|
n = -1
|
|
field = field[1:]
|
|
}
|
|
}
|
|
if field == "" {
|
|
panic("Sort: empty field name")
|
|
}
|
|
order = append(order, bson.DocElem{field, n})
|
|
}
|
|
w.OrderBy = order
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
// Explain returns a number of details about how the MongoDB server would
|
|
// execute the requested query, such as the number of objects examined,
|
|
// the number of time the read lock was yielded to allow writes to go in,
|
|
// and so on.
|
|
//
|
|
// For example:
|
|
//
|
|
// m := bson.M{}
|
|
// err := collection.Find(bson.M{"filename": name}).Explain(m)
|
|
// if err == nil {
|
|
// fmt.Printf("Explain: %#v\n", m)
|
|
// }
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Optimization
|
|
// http://www.mongodb.org/display/DOCS/Query+Optimizer
|
|
//
|
|
func (q *Query) Explain(result interface{}) error {
|
|
q.m.Lock()
|
|
clone := &Query{session: q.session, query: q.query}
|
|
q.m.Unlock()
|
|
w := clone.wrap()
|
|
w.Explain = true
|
|
if clone.op.limit > 0 {
|
|
clone.op.limit = -q.op.limit
|
|
}
|
|
iter := clone.Iter()
|
|
if iter.Next(result) {
|
|
return nil
|
|
}
|
|
return iter.Err()
|
|
}
|
|
|
|
// Hint will include an explicit "hint" in the query to force the server
|
|
// to use a specified index, potentially improving performance in some
|
|
// situations. The provided parameters are the fields that compose the
|
|
// key of the index to be used. For details on how the indexKey may be
|
|
// built, see the EnsureIndex method.
|
|
//
|
|
// For example:
|
|
//
|
|
// query := collection.Find(bson.M{"firstname": "Joe", "lastname": "Winter"})
|
|
// query.Hint("lastname", "firstname")
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Optimization
|
|
// http://www.mongodb.org/display/DOCS/Query+Optimizer
|
|
//
|
|
func (q *Query) Hint(indexKey ...string) *Query {
|
|
q.m.Lock()
|
|
_, realKey, err := parseIndexKey(indexKey)
|
|
w := q.wrap()
|
|
w.Hint = realKey
|
|
q.m.Unlock()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return q
|
|
}
|
|
|
|
// Snapshot will force the performed query to make use of an available
|
|
// index on the _id field to prevent the same document from being returned
|
|
// more than once in a single iteration. This might happen without this
|
|
// setting in situations when the document changes in size and thus has to
|
|
// be moved while the iteration is running.
|
|
//
|
|
// Because snapshot mode traverses the _id index, it may not be used with
|
|
// sorting or explicit hints. It also cannot use any other index for the
|
|
// query.
|
|
//
|
|
// Even with snapshot mode, items inserted or deleted during the query may
|
|
// or may not be returned; that is, this mode is not a true point-in-time
|
|
// snapshot.
|
|
//
|
|
// The same effect of Snapshot may be obtained by using any unique index on
|
|
// field(s) that will not be modified (best to use Hint explicitly too).
|
|
// A non-unique index (such as creation time) may be made unique by
|
|
// appending _id to the index when creating it.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/How+to+do+Snapshotted+Queries+in+the+Mongo+Database
|
|
//
|
|
func (q *Query) Snapshot() *Query {
|
|
q.m.Lock()
|
|
w := q.wrap()
|
|
w.Snapshot = true
|
|
q.m.Unlock()
|
|
return q
|
|
}
|
|
|
|
func checkQueryError(fullname string, d []byte) error {
|
|
l := len(d)
|
|
if l < 16 {
|
|
return nil
|
|
}
|
|
if d[5] == '$' && d[6] == 'e' && d[7] == 'r' && d[8] == 'r' && d[9] == '\x00' && d[4] == '\x02' {
|
|
goto Error
|
|
}
|
|
if len(fullname) < 5 || fullname[len(fullname)-5:] != ".$cmd" {
|
|
return nil
|
|
}
|
|
for i := 0; i+8 < l; i++ {
|
|
if d[i] == '\x02' && d[i+1] == 'e' && d[i+2] == 'r' && d[i+3] == 'r' && d[i+4] == 'm' && d[i+5] == 's' && d[i+6] == 'g' && d[i+7] == '\x00' {
|
|
goto Error
|
|
}
|
|
}
|
|
return nil
|
|
|
|
Error:
|
|
result := &queryError{}
|
|
bson.Unmarshal(d, result)
|
|
if result.LastError != nil {
|
|
return result.LastError
|
|
}
|
|
if result.Err == "" && result.ErrMsg == "" {
|
|
return nil
|
|
}
|
|
if result.AssertionCode != 0 && result.Assertion != "" {
|
|
return &QueryError{Code: result.AssertionCode, Message: result.Assertion, Assertion: true}
|
|
}
|
|
if result.Err != "" {
|
|
return &QueryError{Code: result.Code, Message: result.Err}
|
|
}
|
|
return &QueryError{Code: result.Code, Message: result.ErrMsg}
|
|
}
|
|
|
|
// One executes the query and unmarshals the first obtained document into the
|
|
// result argument. The result must be a struct or map value capable of being
|
|
// unmarshalled into by gobson. This function blocks until either a result
|
|
// is available or an error happens. For example:
|
|
//
|
|
// err := collection.Find(bson.M{"a", 1}).One(&result)
|
|
//
|
|
// In case the resulting document includes a field named $err or errmsg, which
|
|
// are standard ways for MongoDB to return query errors, the returned err will
|
|
// be set to a *QueryError value including the Err message and the Code. In
|
|
// those cases, the result argument is still unmarshalled into with the
|
|
// received document so that any other custom values may be obtained if
|
|
// desired.
|
|
//
|
|
func (q *Query) One(result interface{}) (err error) {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op // Copy.
|
|
q.m.Unlock()
|
|
|
|
socket, err := session.acquireSocket(true)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer socket.Release()
|
|
|
|
op.flags |= session.slaveOkFlag()
|
|
op.limit = -1
|
|
|
|
data, err := socket.SimpleQuery(&op)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if data == nil {
|
|
return ErrNotFound
|
|
}
|
|
if result != nil {
|
|
err = bson.Unmarshal(data, result)
|
|
if err == nil {
|
|
debugf("Query %p document unmarshaled: %#v", q, result)
|
|
} else {
|
|
debugf("Query %p document unmarshaling failed: %#v", q, err)
|
|
return err
|
|
}
|
|
}
|
|
return checkQueryError(op.collection, data)
|
|
}
|
|
|
|
// The DBRef type implements support for the database reference MongoDB
|
|
// convention as supported by multiple drivers. This convention enables
|
|
// cross-referencing documents between collections and databases using
|
|
// a structure which includes a collection name, a document id, and
|
|
// optionally a database name.
|
|
//
|
|
// See the FindRef methods on Session and on Database.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Database+References
|
|
//
|
|
type DBRef struct {
|
|
Collection string `bson:"$ref"`
|
|
Id interface{} `bson:"$id"`
|
|
Database string `bson:"$db,omitempty"`
|
|
}
|
|
|
|
// NOTE: Order of fields for DBRef above does matter, per documentation.
|
|
|
|
// FindRef returns a query that looks for the document in the provided
|
|
// reference. If the reference includes the DB field, the document will
|
|
// be retrieved from the respective database.
|
|
//
|
|
// See also the DBRef type and the FindRef method on Session.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Database+References
|
|
//
|
|
func (db *Database) FindRef(ref *DBRef) *Query {
|
|
var c *Collection
|
|
if ref.Database == "" {
|
|
c = db.C(ref.Collection)
|
|
} else {
|
|
c = db.Session.DB(ref.Database).C(ref.Collection)
|
|
}
|
|
return c.FindId(ref.Id)
|
|
}
|
|
|
|
// FindRef returns a query that looks for the document in the provided
|
|
// reference. For a DBRef to be resolved correctly at the session level
|
|
// it must necessarily have the optional DB field defined.
|
|
//
|
|
// See also the DBRef type and the FindRef method on Database.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Database+References
|
|
//
|
|
func (s *Session) FindRef(ref *DBRef) *Query {
|
|
if ref.Database == "" {
|
|
panic(errors.New(fmt.Sprintf("Can't resolve database for %#v", ref)))
|
|
}
|
|
c := s.DB(ref.Database).C(ref.Collection)
|
|
return c.FindId(ref.Id)
|
|
}
|
|
|
|
// CollectionNames returns the collection names present in database.
|
|
func (db *Database) CollectionNames() (names []string, err error) {
|
|
c := len(db.Name) + 1
|
|
var result *struct{ Name string }
|
|
err = db.C("system.namespaces").Find(nil).For(&result, func() error {
|
|
if strings.Index(result.Name, "$") < 0 || strings.Index(result.Name, ".oplog.$") >= 0 {
|
|
names = append(names, result.Name[c:])
|
|
}
|
|
return nil
|
|
})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
sort.StringSlice(names).Sort()
|
|
return names, nil
|
|
}
|
|
|
|
type dbNames struct {
|
|
Databases []struct {
|
|
Name string
|
|
Empty bool
|
|
}
|
|
}
|
|
|
|
// DatabaseNames returns the names of non-empty databases present in the cluster.
|
|
func (s *Session) DatabaseNames() (names []string, err error) {
|
|
var result dbNames
|
|
err = s.Run("listDatabases", &result)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
for _, db := range result.Databases {
|
|
if !db.Empty {
|
|
names = append(names, db.Name)
|
|
}
|
|
}
|
|
return names, nil
|
|
}
|
|
|
|
// Iter executes the query and returns an iterator capable of going over all
|
|
// the results. Results will be returned in batches of configurable
|
|
// size (see the Batch method) and more documents will be requested when a
|
|
// configurable number of documents is iterated over (see the Prefetch method).
|
|
func (q *Query) Iter() *Iter {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op
|
|
prefetch := q.prefetch
|
|
limit := q.limit
|
|
q.m.Unlock()
|
|
|
|
iter := &Iter{session: session, prefetch: prefetch, limit: limit}
|
|
iter.gotReply.L = &iter.m
|
|
iter.op.collection = op.collection
|
|
iter.op.limit = op.limit
|
|
iter.op.replyFunc = iter.replyFunc()
|
|
iter.pendingDocs++
|
|
op.replyFunc = iter.op.replyFunc
|
|
op.flags |= session.slaveOkFlag()
|
|
|
|
socket, err := session.acquireSocket(true)
|
|
if err != nil {
|
|
iter.err = err
|
|
} else {
|
|
iter.err = socket.Query(&op)
|
|
socket.Release()
|
|
}
|
|
return iter
|
|
}
|
|
|
|
// Tail returns a tailable iterator. Unlike a normal iterator, a
|
|
// tailable iterator may wait for new values to be inserted in the
|
|
// collection once the end of the current result set is reached,
|
|
// A tailable iterator may only be used with capped collections.
|
|
//
|
|
// The timeout parameter indicates how long Next will block waiting
|
|
// for a result before timing out. If set to -1, Next will not
|
|
// timeout, and will continue waiting for a result for as long as
|
|
// the cursor is valid and the session is not closed. If set to 0,
|
|
// Next times out as soon as it reaches the end of the result set.
|
|
// Otherwise, Next will wait for at least the given number of
|
|
// seconds for a new document to be available before timing out.
|
|
//
|
|
// On timeouts, Next will unblock and return false, and the Timeout
|
|
// method will return true if called. In these cases, Next may still
|
|
// be called again on the same iterator to check if a new value is
|
|
// available at the current cursor position, and again it will block
|
|
// according to the specified timeoutSecs. If the cursor becomes
|
|
// invalid, though, both Next and Timeout will return false and
|
|
// the query must be restarted.
|
|
//
|
|
// The following example demonstrates timeout handling and query
|
|
// restarting:
|
|
//
|
|
// iter := collection.Find(nil).Sort("$natural").Tail(5 * time.Second)
|
|
// for {
|
|
// for iter.Next(&result) {
|
|
// fmt.Println(result.Id)
|
|
// lastId = result.Id
|
|
// }
|
|
// if iter.Err() != nil {
|
|
// panic(err)
|
|
// }
|
|
// if iter.Timeout() {
|
|
// continue
|
|
// }
|
|
// query := collection.Find(bson.M{"_id", bson.M{"$gt", lastId}})
|
|
// iter = query.Sort("$natural").Tail(5 * time.Second)
|
|
// }
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Tailable+Cursors
|
|
// http://www.mongodb.org/display/DOCS/Capped+Collections
|
|
// http://www.mongodb.org/display/DOCS/Sorting+and+Natural+Order
|
|
//
|
|
func (q *Query) Tail(timeout time.Duration) *Iter {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op
|
|
prefetch := q.prefetch
|
|
q.m.Unlock()
|
|
|
|
iter := &Iter{session: session, prefetch: prefetch}
|
|
iter.gotReply.L = &iter.m
|
|
iter.timeout = timeout
|
|
iter.op.collection = op.collection
|
|
iter.op.limit = op.limit
|
|
iter.op.replyFunc = iter.replyFunc()
|
|
iter.pendingDocs++
|
|
op.replyFunc = iter.op.replyFunc
|
|
op.flags |= 2 | 32 | session.slaveOkFlag() // Tailable | AwaitData [| SlaveOk]
|
|
|
|
socket, err := session.acquireSocket(true)
|
|
if err != nil {
|
|
iter.err = err
|
|
} else {
|
|
iter.err = socket.Query(&op)
|
|
socket.Release()
|
|
}
|
|
return iter
|
|
}
|
|
|
|
func (s *Session) slaveOkFlag() (flag uint32) {
|
|
s.m.RLock()
|
|
if s.slaveOk {
|
|
flag = 4
|
|
}
|
|
s.m.RUnlock()
|
|
return
|
|
}
|
|
|
|
// Err returns nil if no errors happened during iteration, or the actual
|
|
// error otherwise.
|
|
//
|
|
// In case a resulting document included a field named $err or errmsg, which are
|
|
// standard ways for MongoDB to report an improper query, the returned value has
|
|
// a *QueryError type, and includes the Err message and the Code.
|
|
func (iter *Iter) Err() error {
|
|
iter.m.Lock()
|
|
err := iter.err
|
|
iter.m.Unlock()
|
|
if err == ErrNotFound {
|
|
return nil
|
|
}
|
|
return err
|
|
}
|
|
|
|
// Timeout returns true if Next returned false due to a timeout of
|
|
// a tailable cursor. In those cases, Next may be called again to continue
|
|
// the iteration at the previous cursor position.
|
|
func (iter *Iter) Timeout() bool {
|
|
iter.m.Lock()
|
|
result := iter.timedout
|
|
iter.m.Unlock()
|
|
return result
|
|
}
|
|
|
|
// Next retrieves the next document from the result set, blocking if necessary.
|
|
// This method will also automatically retrieve another batch of documents from
|
|
// the server when the current one is exhausted, or before that in background
|
|
// if pre-fetching is enabled (see the Query.Prefetch and Session.SetPrefetch
|
|
// methods).
|
|
//
|
|
// Next returns true if a document was successfully unmarshalled onto result,
|
|
// and false at the end of the result set or if an error happened.
|
|
// When Next returns false, the Err method should be called to verify if
|
|
// there was an error during iteration.
|
|
//
|
|
// For example:
|
|
//
|
|
// iter := collection.Find(nil).Iter()
|
|
// for iter.Next(&result) {
|
|
// fmt.Printf("Result: %v\n", result.Id)
|
|
// }
|
|
// if iter.Err() != nil {
|
|
// panic(iter.Err())
|
|
// }
|
|
//
|
|
func (iter *Iter) Next(result interface{}) bool {
|
|
timeouts := false
|
|
timeout := time.Time{}
|
|
if iter.timeout >= 0 {
|
|
timeouts = true
|
|
timeout = time.Now().Add(iter.timeout)
|
|
}
|
|
|
|
iter.m.Lock()
|
|
iter.timedout = false
|
|
for iter.err == nil && iter.docData.Len() == 0 && (iter.pendingDocs > 0 || iter.op.cursorId != 0) {
|
|
if iter.pendingDocs == 0 && iter.op.cursorId != 0 {
|
|
// Tailable cursor exhausted.
|
|
if timeouts && time.Now().After(timeout) {
|
|
iter.timedout = true
|
|
iter.m.Unlock()
|
|
return false
|
|
}
|
|
iter.getMore()
|
|
}
|
|
iter.gotReply.Wait()
|
|
}
|
|
|
|
// Exhaust available data before reporting any errors.
|
|
if docData, ok := iter.docData.Pop().([]byte); ok {
|
|
iter.limit--
|
|
if iter.limit == 0 {
|
|
// XXX Must kill the cursor here.
|
|
iter.err = ErrNotFound
|
|
}
|
|
if iter.op.cursorId != 0 && iter.err == nil {
|
|
iter.docsBeforeMore--
|
|
if iter.docsBeforeMore == 0 {
|
|
iter.getMore()
|
|
}
|
|
}
|
|
iter.m.Unlock()
|
|
err := bson.Unmarshal(docData, result)
|
|
if err != nil {
|
|
debugf("Iter %p document unmarshaling failed: %#v", iter, err)
|
|
iter.err = err
|
|
return false
|
|
}
|
|
debugf("Iter %p document unmarshaled: %#v", iter, result)
|
|
// XXX Only have to check first document for a query error?
|
|
err = checkQueryError(iter.op.collection, docData)
|
|
if err != nil {
|
|
iter.err = err
|
|
return false
|
|
}
|
|
return true
|
|
} else if iter.err != nil {
|
|
debugf("Iter %p returning false: %s", iter, iter.err)
|
|
iter.m.Unlock()
|
|
return false
|
|
} else if iter.op.cursorId == 0 {
|
|
iter.err = ErrNotFound
|
|
debugf("Iter %p exhausted with cursor=0", iter)
|
|
iter.m.Unlock()
|
|
return false
|
|
}
|
|
|
|
panic("unreachable")
|
|
}
|
|
|
|
// All retrieves all documents from the result set into the provided slice.
|
|
//
|
|
// The result argument must necessarily be the address for a slice. The slice
|
|
// may be nil or previously allocated.
|
|
//
|
|
// WARNING: Obviously, All must not be used with result sets that may be
|
|
// potentially large, since it may consume all memory until the system
|
|
// crashes. Consider building the query with a Limit clause to ensure the
|
|
// result size is bounded.
|
|
//
|
|
// For instance:
|
|
//
|
|
// var result []struct{ Value int }
|
|
// iter := collection.Find(nil).Limit(100).Iter()
|
|
// err := iter.All(&result)
|
|
// if err != nil {
|
|
// panic(iter.Err())
|
|
// }
|
|
//
|
|
func (iter *Iter) All(result interface{}) error {
|
|
resultv := reflect.ValueOf(result)
|
|
if resultv.Kind() != reflect.Ptr || resultv.Elem().Kind() != reflect.Slice {
|
|
panic("result argument must be a slice address")
|
|
}
|
|
slicev := resultv.Elem()
|
|
slicev = slicev.Slice(0, slicev.Cap())
|
|
elemt := slicev.Type().Elem()
|
|
i := 0
|
|
for {
|
|
if slicev.Len() == i {
|
|
elemp := reflect.New(elemt)
|
|
if !iter.Next(elemp.Interface()) {
|
|
break
|
|
}
|
|
slicev = reflect.Append(slicev, elemp.Elem())
|
|
slicev = slicev.Slice(0, slicev.Cap())
|
|
} else {
|
|
if !iter.Next(slicev.Index(i).Addr().Interface()) {
|
|
break
|
|
}
|
|
}
|
|
i++
|
|
}
|
|
resultv.Elem().Set(slicev.Slice(0, i))
|
|
return iter.Err()
|
|
}
|
|
|
|
// All works like Iter.All.
|
|
func (q *Query) All(result interface{}) error {
|
|
return q.Iter().All(result)
|
|
}
|
|
|
|
// The For method is obsolete and will be removed in a future release.
|
|
// See Iter as an elegant replacement.
|
|
func (q *Query) For(result interface{}, f func() error) error {
|
|
return q.Iter().For(result, f)
|
|
}
|
|
|
|
// The For method is obsolete and will be removed in a future release.
|
|
// See Iter as an elegant replacement.
|
|
func (iter *Iter) For(result interface{}, f func() error) (err error) {
|
|
valid := false
|
|
v := reflect.ValueOf(result)
|
|
if v.Kind() == reflect.Ptr {
|
|
v = v.Elem()
|
|
switch v.Kind() {
|
|
case reflect.Map, reflect.Ptr, reflect.Interface, reflect.Slice:
|
|
valid = v.IsNil()
|
|
}
|
|
}
|
|
if !valid {
|
|
panic("For needs a pointer to nil reference value. See the documentation.")
|
|
}
|
|
zero := reflect.Zero(v.Type())
|
|
for {
|
|
v.Set(zero)
|
|
if !iter.Next(result) {
|
|
break
|
|
}
|
|
err = f()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return iter.Err()
|
|
}
|
|
|
|
func (iter *Iter) getMore() {
|
|
socket, err := iter.session.acquireSocket(true)
|
|
if err != nil {
|
|
iter.err = err
|
|
return
|
|
}
|
|
defer socket.Release()
|
|
|
|
debugf("Iter %p requesting more documents", iter)
|
|
iter.pendingDocs++
|
|
if iter.limit > 0 && iter.op.limit > iter.limit {
|
|
iter.op.limit = iter.limit
|
|
}
|
|
if iter.op.limit == 1 {
|
|
iter.op.limit = -1
|
|
}
|
|
err = socket.Query(&iter.op)
|
|
if err != nil {
|
|
iter.err = err
|
|
}
|
|
}
|
|
|
|
type countCmd struct {
|
|
Count string
|
|
Query interface{}
|
|
Limit int32 ",omitempty"
|
|
Skip int32 ",omitempty"
|
|
}
|
|
|
|
// Count returns the total number of documents in the result set.
|
|
func (q *Query) Count() (n int, err error) {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op
|
|
limit := q.limit
|
|
q.m.Unlock()
|
|
|
|
c := strings.Index(op.collection, ".")
|
|
if c < 0 {
|
|
return 0, errors.New("Bad collection name: " + op.collection)
|
|
}
|
|
|
|
dbname := op.collection[:c]
|
|
cname := op.collection[c+1:]
|
|
|
|
qdoc := op.query
|
|
if wrapper, ok := qdoc.(*queryWrapper); ok {
|
|
qdoc = wrapper.Query
|
|
}
|
|
|
|
result := struct{ N int }{}
|
|
err = session.DB(dbname).Run(countCmd{cname, qdoc, limit, op.skip}, &result)
|
|
return result.N, err
|
|
}
|
|
|
|
// Count returns the total number of documents in the collection.
|
|
func (c *Collection) Count() (n int, err error) {
|
|
return c.Find(nil).Count()
|
|
}
|
|
|
|
type distinctCmd struct {
|
|
Collection string "distinct"
|
|
Key string
|
|
Query interface{} ",omitempty"
|
|
}
|
|
|
|
// Distinct returns a list of distinct values for the given key within
|
|
// the result set. The list of distinct values will be unmarshalled
|
|
// in the "values" key of the provided result parameter.
|
|
//
|
|
// For example:
|
|
//
|
|
// var result []int
|
|
// err := collection.Find(bson.M{"gender": "F"}).Distinct("age", &result)
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/Aggregation
|
|
//
|
|
func (q *Query) Distinct(key string, result interface{}) error {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op // Copy.
|
|
q.m.Unlock()
|
|
|
|
c := strings.Index(op.collection, ".")
|
|
if c < 0 {
|
|
return errors.New("Bad collection name: " + op.collection)
|
|
}
|
|
|
|
dbname := op.collection[:c]
|
|
cname := op.collection[c+1:]
|
|
|
|
qdoc := op.query
|
|
if wrapper, ok := qdoc.(*queryWrapper); ok {
|
|
qdoc = wrapper.Query
|
|
}
|
|
|
|
var doc struct{ Values bson.Raw }
|
|
err := session.DB(dbname).Run(distinctCmd{cname, key, qdoc}, &doc)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
return doc.Values.Unmarshal(result)
|
|
}
|
|
|
|
type mapReduceCmd struct {
|
|
Collection string "mapreduce"
|
|
Map string ",omitempty"
|
|
Reduce string ",omitempty"
|
|
Finalize string ",omitempty"
|
|
Limit int32 ",omitempty"
|
|
Out interface{}
|
|
Query interface{} ",omitempty"
|
|
Sort interface{} ",omitempty"
|
|
Scope interface{} ",omitempty"
|
|
Verbose bool ",omitempty"
|
|
}
|
|
|
|
type mapReduceResult struct {
|
|
Results bson.Raw
|
|
Result bson.Raw
|
|
TimeMillis int64 "timeMillis"
|
|
Counts struct{ Input, Emit, Output int }
|
|
Ok bool
|
|
Err string
|
|
Timing *MapReduceTime
|
|
}
|
|
|
|
type MapReduce struct {
|
|
Map string // Map Javascript function code (required)
|
|
Reduce string // Reduce Javascript function code (required)
|
|
Finalize string // Finalize Javascript function code (optional)
|
|
Out interface{} // Output collection name or document. If nil, results are inlined into the result parameter.
|
|
Scope interface{} // Optional global scope for Javascript functions
|
|
Verbose bool
|
|
}
|
|
|
|
type MapReduceInfo struct {
|
|
InputCount int // Number of documents mapped
|
|
EmitCount int // Number of times reduce called emit
|
|
OutputCount int // Number of documents in resulting collection
|
|
Database string // Output database, if results are not inlined
|
|
Collection string // Output collection, if results are not inlined
|
|
Time int64 // Time to run the job, in nanoseconds
|
|
VerboseTime *MapReduceTime // Only defined if Verbose was true
|
|
}
|
|
|
|
type MapReduceTime struct {
|
|
Total int64 // Total time, in nanoseconds
|
|
Map int64 "mapTime" // Time within map function, in nanoseconds
|
|
EmitLoop int64 "emitLoop" // Time within the emit/map loop, in nanoseconds
|
|
}
|
|
|
|
// MapReduce executes a map/reduce job for documents covered by the query.
|
|
// That kind of job is suitable for very flexible bulk aggregation of data
|
|
// performed at the server side via Javascript functions.
|
|
//
|
|
// Results from the job may be returned as a result of the query itself
|
|
// through the result parameter in case they'll certainly fit in memory
|
|
// and in a single document. If there's the possibility that the amount
|
|
// of data might be too large, results must be stored back in an alternative
|
|
// collection or even a separate database, by setting the Out field of the
|
|
// provided MapReduce job. In that case, provide nil as the result parameter.
|
|
//
|
|
// These are some of the ways to set Out:
|
|
//
|
|
// nil
|
|
// Inline results into the result parameter.
|
|
//
|
|
// bson.M{"replace": "mycollection"}
|
|
// The output will be inserted into a collection which replaces any
|
|
// existing collection with the same name.
|
|
//
|
|
// bson.M{"merge": "mycollection"}
|
|
// This option will merge new data into the old output collection. In
|
|
// other words, if the same key exists in both the result set and the
|
|
// old collection, the new key will overwrite the old one.
|
|
//
|
|
// bson.M{"reduce": "mycollection"}
|
|
// If documents exist for a given key in the result set and in the old
|
|
// collection, then a reduce operation (using the specified reduce
|
|
// function) will be performed on the two values and the result will be
|
|
// written to the output collection. If a finalize function was
|
|
// provided, this will be run after the reduce as well.
|
|
//
|
|
// bson.M{...., "db": "mydb"}
|
|
// Any of the above options can have the "db" key included for doing
|
|
// the respective action in a separate database.
|
|
//
|
|
// The following is a trivial example which will count the number of
|
|
// occurrences of a field named n on each document in a collection, and
|
|
// will return results inline:
|
|
//
|
|
// job := &mgo.MapReduce{
|
|
// Map: "function() { emit(this.n, 1) }",
|
|
// Reduce: "function(key, values) { return Array.sum(values) }",
|
|
// }
|
|
// var result []struct { Id int "_id"; Value int }
|
|
// _, err := collection.Find(nil).MapReduce(job, &result)
|
|
// if err != nil {
|
|
// panic(err)
|
|
// }
|
|
// for _, item := range result {
|
|
// fmt.Println(item.Value)
|
|
// }
|
|
//
|
|
// This function is compatible with MongoDB 1.7.4+.
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/MapReduce
|
|
//
|
|
func (q *Query) MapReduce(job *MapReduce, result interface{}) (info *MapReduceInfo, err error) {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op // Copy.
|
|
limit := q.limit
|
|
q.m.Unlock()
|
|
|
|
c := strings.Index(op.collection, ".")
|
|
if c < 0 {
|
|
return nil, errors.New("Bad collection name: " + op.collection)
|
|
}
|
|
|
|
dbname := op.collection[:c]
|
|
cname := op.collection[c+1:]
|
|
|
|
qdoc := op.query
|
|
var sort interface{}
|
|
if wrapper, ok := qdoc.(*queryWrapper); ok {
|
|
qdoc = wrapper.Query
|
|
sort = wrapper.OrderBy
|
|
}
|
|
|
|
cmd := mapReduceCmd{
|
|
Collection: cname,
|
|
Map: job.Map,
|
|
Reduce: job.Reduce,
|
|
Finalize: job.Finalize,
|
|
Out: job.Out,
|
|
Scope: job.Scope,
|
|
Verbose: job.Verbose,
|
|
Query: qdoc,
|
|
Sort: sort,
|
|
Limit: limit,
|
|
}
|
|
|
|
if cmd.Out == nil {
|
|
cmd.Out = bson.M{"inline": 1}
|
|
}
|
|
|
|
var doc mapReduceResult
|
|
err = session.DB(dbname).Run(&cmd, &doc)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if doc.Err != "" {
|
|
return nil, errors.New(doc.Err)
|
|
}
|
|
|
|
info = &MapReduceInfo{
|
|
InputCount: doc.Counts.Input,
|
|
EmitCount: doc.Counts.Emit,
|
|
OutputCount: doc.Counts.Output,
|
|
Time: doc.TimeMillis * 1e6,
|
|
}
|
|
|
|
if doc.Result.Kind == 0x02 {
|
|
err = doc.Result.Unmarshal(&info.Collection)
|
|
info.Database = dbname
|
|
} else if doc.Result.Kind == 0x03 {
|
|
var v struct{ Collection, Db string }
|
|
err = doc.Result.Unmarshal(&v)
|
|
info.Collection = v.Collection
|
|
info.Database = v.Db
|
|
}
|
|
|
|
if doc.Timing != nil {
|
|
info.VerboseTime = doc.Timing
|
|
info.VerboseTime.Total *= 1e6
|
|
info.VerboseTime.Map *= 1e6
|
|
info.VerboseTime.EmitLoop *= 1e6
|
|
}
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if result != nil {
|
|
return info, doc.Results.Unmarshal(result)
|
|
}
|
|
return info, nil
|
|
}
|
|
|
|
type Change struct {
|
|
Update interface{} // The change document
|
|
Upsert bool // Whether to insert in case the document isn't found
|
|
Remove bool // Whether to remove the document found rather than updating
|
|
ReturnNew bool // Should the modified document be returned rather than the old one
|
|
}
|
|
|
|
type findModifyCmd struct {
|
|
Collection string "findAndModify"
|
|
Query, Update, Sort, Fields interface{} ",omitempty"
|
|
Upsert, Remove, New bool ",omitempty"
|
|
}
|
|
|
|
type valueResult struct {
|
|
Value bson.Raw
|
|
LastError LastError "lastErrorObject"
|
|
}
|
|
|
|
// Apply allows updating, upserting or removing a document matching a query
|
|
// and atomically returning either the old version (the default) or the new
|
|
// version of the document (when ReturnNew is true). If no objects are
|
|
// found Apply returns ErrNotFound.
|
|
//
|
|
// The Sort and Select query methods affect the result of Apply. In case
|
|
// multiple documents match the query, Sort enables selecting which document to
|
|
// act upon by ordering it first. Select enables retrieving only a selection
|
|
// of fields of the new or old document.
|
|
//
|
|
// This simple example increments a counter and prints its new value:
|
|
//
|
|
// change := mgo.Change{
|
|
// Update: bson.M{"$inc": bson.M{"n": 1}},
|
|
// ReturnNew: true,
|
|
// }
|
|
// info, err = col.Find(M{"_id": id}).Apply(change, &doc)
|
|
// fmt.Println(doc.N)
|
|
//
|
|
// Relevant documentation:
|
|
//
|
|
// http://www.mongodb.org/display/DOCS/findAndModify+Command
|
|
// http://www.mongodb.org/display/DOCS/Updating
|
|
// http://www.mongodb.org/display/DOCS/Atomic+Operations
|
|
//
|
|
func (q *Query) Apply(change Change, result interface{}) (info *ChangeInfo, err error) {
|
|
q.m.Lock()
|
|
session := q.session
|
|
op := q.op // Copy.
|
|
q.m.Unlock()
|
|
|
|
c := strings.Index(op.collection, ".")
|
|
if c < 0 {
|
|
return nil, errors.New("bad collection name: " + op.collection)
|
|
}
|
|
|
|
dbname := op.collection[:c]
|
|
cname := op.collection[c+1:]
|
|
|
|
qdoc := op.query
|
|
var sort interface{}
|
|
if wrapper, ok := qdoc.(*queryWrapper); ok {
|
|
qdoc = wrapper.Query
|
|
sort = wrapper.OrderBy
|
|
}
|
|
|
|
cmd := findModifyCmd{
|
|
Collection: cname,
|
|
Update: change.Update,
|
|
Upsert: change.Upsert,
|
|
Remove: change.Remove,
|
|
New: change.ReturnNew,
|
|
Query: qdoc,
|
|
Sort: sort,
|
|
Fields: op.selector,
|
|
}
|
|
|
|
var doc valueResult
|
|
err = session.DB(dbname).Run(&cmd, &doc)
|
|
if err != nil {
|
|
if qerr, ok := err.(*QueryError); ok && qerr.Message == "No matching object found" {
|
|
return nil, ErrNotFound
|
|
}
|
|
return nil, err
|
|
}
|
|
if doc.Value.Kind == 0x0A {
|
|
return nil, ErrNotFound
|
|
}
|
|
err = doc.Value.Unmarshal(result)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
info = &ChangeInfo{}
|
|
lerr := &doc.LastError
|
|
if lerr.UpdatedExisting {
|
|
info.Updated = lerr.N
|
|
} else if change.Remove {
|
|
info.Removed = lerr.N
|
|
} else if change.Upsert {
|
|
info.UpsertedId = lerr.UpsertedId
|
|
}
|
|
return info, nil
|
|
}
|
|
|
|
// The BuildInfo type encapsulates details about the running MongoDB server.
|
|
//
|
|
// Note that the VersionArray field was introduced in MongoDB 2.0+, but it is
|
|
// internally assembled from the Version information for previous versions.
|
|
// In both cases, VersionArray is guaranteed to have at least 4 entries.
|
|
type BuildInfo struct {
|
|
Version string
|
|
VersionArray []int `bson:"versionArray"` // On MongoDB 2.0+; assembled from Version otherwise
|
|
GitVersion string `bson:"gitVersion"`
|
|
SysInfo string `bson:"sysInfo"`
|
|
Bits int
|
|
Debug bool
|
|
MaxObjectSize int `bson:"maxBsonObjectSize"`
|
|
}
|
|
|
|
// BuildInfo retrieves the version and other details about the
|
|
// running MongoDB server.
|
|
func (s *Session) BuildInfo() (info BuildInfo, err error) {
|
|
err = s.Run(bson.D{{"buildInfo", "1"}}, &info)
|
|
if len(info.VersionArray) == 0 {
|
|
for _, a := range strings.Split(info.Version, ".") {
|
|
i, err := strconv.Atoi(a)
|
|
if err != nil {
|
|
break
|
|
}
|
|
info.VersionArray = append(info.VersionArray, i)
|
|
}
|
|
}
|
|
for len(info.VersionArray) < 4 {
|
|
info.VersionArray = append(info.VersionArray, 0)
|
|
}
|
|
return
|
|
}
|
|
|
|
// ---------------------------------------------------------------------------
|
|
// Internal session handling helpers.
|
|
|
|
func (s *Session) acquireSocket(slaveOk bool) (*mongoSocket, error) {
|
|
|
|
// Try to use a previously reserved socket, with a fast read-only lock.
|
|
s.m.RLock()
|
|
sock := s.socket
|
|
sockIsGood := sock != nil && (slaveOk && s.slaveOk || s.socketIsMaster)
|
|
s.m.RUnlock()
|
|
|
|
if sockIsGood {
|
|
sock.Acquire()
|
|
return sock, nil
|
|
}
|
|
|
|
// No go. We may have to request a new socket and change the session,
|
|
// so try again but with an exclusive lock now.
|
|
s.m.Lock()
|
|
defer s.m.Unlock()
|
|
|
|
sock = s.socket
|
|
sockIsGood = sock != nil && (slaveOk && s.slaveOk || s.socketIsMaster)
|
|
|
|
if sockIsGood {
|
|
sock.Acquire()
|
|
return sock, nil
|
|
}
|
|
|
|
// Still not good. We need a new socket.
|
|
sock, err := s.cluster().AcquireSocket(slaveOk && s.slaveOk, s.syncTimeout)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Authenticate the new socket.
|
|
for _, a := range s.auth {
|
|
err = sock.Login(a.db, a.user, a.pass)
|
|
if err != nil {
|
|
sock.Release()
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
// Keep track of the new socket, if necessary.
|
|
// Note that, as a special case, if the Eventual session was
|
|
// not refreshed (socket != nil), it means the developer asked
|
|
// to preserve an existing reserved socket, so we'll keep the
|
|
// master one around too before a Refresh happens.
|
|
if s.consistency != Eventual || s.socket != nil {
|
|
s.setSocket(sock)
|
|
}
|
|
|
|
// Switch over a Monotonic session to the master.
|
|
if !slaveOk && s.consistency == Monotonic {
|
|
s.slaveOk = false
|
|
}
|
|
|
|
return sock, nil
|
|
}
|
|
|
|
// Set the socket bound to this session. With a bound socket, all operations
|
|
// with this session will use the given socket if possible. When not possible
|
|
// (e.g. attempting to write to a slave) acquireSocket will replace the
|
|
// current socket. Note that this method will properly refcount the socket up
|
|
// and down when setting/releasing.
|
|
func (s *Session) setSocket(socket *mongoSocket) {
|
|
if socket != nil {
|
|
s.socketIsMaster = socket.Acquire()
|
|
} else {
|
|
s.socketIsMaster = false
|
|
}
|
|
if s.socket != nil {
|
|
s.socket.Release()
|
|
}
|
|
s.socket = socket
|
|
}
|
|
|
|
func (iter *Iter) replyFunc() replyFunc {
|
|
return func(err error, op *replyOp, docNum int, docData []byte) {
|
|
iter.m.Lock()
|
|
iter.pendingDocs--
|
|
if err != nil {
|
|
iter.err = err
|
|
debugf("Iter %p received an error: %s", iter, err.Error())
|
|
} else if docNum == -1 {
|
|
debugf("Iter %p received no documents (cursor=%d).", iter, op.cursorId)
|
|
if op != nil && op.cursorId != 0 {
|
|
// It's a tailable cursor.
|
|
iter.op.cursorId = op.cursorId
|
|
} else {
|
|
iter.err = ErrNotFound
|
|
}
|
|
} else {
|
|
rdocs := int(op.replyDocs)
|
|
if docNum == 0 {
|
|
iter.pendingDocs += rdocs - 1
|
|
iter.docsBeforeMore = rdocs - int(iter.prefetch*float64(rdocs))
|
|
iter.op.cursorId = op.cursorId
|
|
}
|
|
// XXX Handle errors and flags.
|
|
debugf("Iter %p received reply document %d/%d (cursor=%d)", iter, docNum+1, rdocs, op.cursorId)
|
|
iter.docData.Push(docData)
|
|
}
|
|
iter.gotReply.Broadcast()
|
|
iter.m.Unlock()
|
|
}
|
|
}
|
|
|
|
// writeQuery runs the given modifying operation, potentially followed up
|
|
// by a getLastError command in case the session is in safe mode. The
|
|
// LastError result is made available in lerr, and if lerr.Err is set it
|
|
// will also be returned as err.
|
|
func (s *Session) writeQuery(op interface{}) (lerr *LastError, err error) {
|
|
socket, err := s.acquireSocket(false)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer socket.Release()
|
|
|
|
s.m.RLock()
|
|
safeOp := s.safeOp
|
|
s.m.RUnlock()
|
|
|
|
if safeOp == nil {
|
|
return nil, socket.Query(op)
|
|
} else {
|
|
var mutex sync.Mutex
|
|
var replyData []byte
|
|
var replyErr error
|
|
mutex.Lock()
|
|
query := *safeOp // Copy the data.
|
|
query.replyFunc = func(err error, reply *replyOp, docNum int, docData []byte) {
|
|
replyData = docData
|
|
replyErr = err
|
|
mutex.Unlock()
|
|
}
|
|
err = socket.Query(op, &query)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
mutex.Lock() // Wait.
|
|
if replyErr != nil {
|
|
return nil, replyErr // XXX TESTME
|
|
}
|
|
result := &LastError{}
|
|
bson.Unmarshal(replyData, &result)
|
|
debugf("Result from writing query: %#v", result)
|
|
if result.Err != "" {
|
|
return result, result
|
|
}
|
|
return result, nil
|
|
}
|
|
panic("unreachable")
|
|
}
|