mirror of https://github.com/perkeep/perkeep.git
124 lines
2.8 KiB
Go
124 lines
2.8 KiB
Go
/*
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Copyright 2011 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package s3
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import (
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"bytes"
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"crypto/md5"
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"errors"
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"hash"
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"io"
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"io/ioutil"
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"math/rand"
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"os"
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"strconv"
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"camlistore.org/pkg/blob"
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)
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const maxInMemorySlurp = 4 << 20 // 4MB. *shrug*
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// amazonSlurper slurps up a blob to memory (or spilling to disk if
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// over maxInMemorySlurp) to verify its digest (and also gets its MD5
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// for Amazon's Content-MD5 header, even if the original blobref
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// is e.g. sha1-xxxx)
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type amazonSlurper struct {
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blob blob.Ref // only used for tempfile's prefix
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buf *bytes.Buffer
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md5 hash.Hash
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file *os.File // nil until allocated
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reading bool // transitions at most once from false -> true
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}
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func newAmazonSlurper(blob blob.Ref) *amazonSlurper {
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return &amazonSlurper{
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blob: blob,
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buf: new(bytes.Buffer),
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md5: md5.New(),
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}
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}
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func (as *amazonSlurper) Read(p []byte) (n int, err error) {
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if !as.reading {
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as.reading = true
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if as.file != nil {
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as.file.Seek(0, 0)
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}
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}
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if as.file != nil {
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return as.file.Read(p)
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}
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return as.buf.Read(p)
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}
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func (as *amazonSlurper) Write(p []byte) (n int, err error) {
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if as.reading {
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panic("write after read")
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}
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as.md5.Write(p)
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if as.file != nil {
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n, err = as.file.Write(p)
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return
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}
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if as.buf.Len()+len(p) > maxInMemorySlurp {
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as.file, err = ioutil.TempFile("", as.blob.String())
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if err != nil {
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return
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}
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_, err = io.Copy(as.file, as.buf)
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if err != nil {
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return
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}
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as.buf = nil
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n, err = as.file.Write(p)
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return
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}
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return as.buf.Write(p)
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}
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func (as *amazonSlurper) Cleanup() {
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if as.file != nil {
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os.Remove(as.file.Name())
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}
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}
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var failPercent, _ = strconv.Atoi(os.Getenv("CAMLI_S3_FAIL_PERCENT"))
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func (sto *s3Storage) ReceiveBlob(b blob.Ref, source io.Reader) (sr blob.SizedRef, err error) {
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slurper := newAmazonSlurper(b)
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defer slurper.Cleanup()
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size, err := io.Copy(slurper, source)
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if err != nil {
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return sr, err
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}
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if failPercent > 0 && failPercent > rand.Intn(100) {
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// TODO(bradfitz): move this to its own package/type, for re-use in
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// many places.
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return sr, errors.New("fake injected error for testing")
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}
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err = sto.s3Client.PutObject(b.String(), sto.bucket, slurper.md5, size, slurper)
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if err != nil {
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return sr, err
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}
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return blob.SizedRef{Ref: b, Size: uint32(size)}, nil
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}
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