mirror of https://github.com/perkeep/perkeep.git
108 lines
2.8 KiB
Go
108 lines
2.8 KiB
Go
/*
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Copyright 2018 The Perkeep Authors
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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 images // import "perkeep.org/internal/images"
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import (
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"bufio"
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"bytes"
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"errors"
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"fmt"
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"log"
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"os/exec"
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"strings"
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"go4.org/syncutil"
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)
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// TODO(mpl): refactor somewhere with pkg/test/dockertest
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const thumbnailImage = "gcr.io/perkeep-containers/thumbnail" // without version
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const thumbnailImageID = "sha256:6b810d57896125f25d5d009328e102dc444d95e7b6d5891f19932bd76244c4c3"
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var (
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thumbnailPullGate = syncutil.NewGate(1)
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haveThumbnailImage bool
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)
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func setUpThumbnailContainer() error {
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if !haveDocker() {
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return errors.New("'docker' command not found")
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}
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thumbnailPullGate.Start()
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defer thumbnailPullGate.Done()
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if haveThumbnailImage {
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return nil
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}
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if ok, err := haveImageID(thumbnailImage, thumbnailImageID); !ok || err != nil {
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if err != nil {
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return fmt.Errorf("error running docker to check for %s: %v", thumbnailImage, err)
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}
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log.Printf("pulling docker image %s ...", thumbnailImage)
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if err := pull(thumbnailImage); err != nil {
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return fmt.Errorf("error pulling %s: %v", thumbnailImage, err)
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}
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}
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haveThumbnailImage = true
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return nil
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}
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// haveDocker returns whether the "docker" command was found.
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func haveDocker() bool {
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_, err := exec.LookPath("docker")
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return err == nil
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}
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func haveImageID(name, id string) (ok bool, err error) {
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out, err := exec.Command(
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"docker",
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"images",
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"--quiet",
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"--no-trunc",
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"--format",
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"{{.ID}}",
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name,
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).Output()
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if err != nil {
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return false, err
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}
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scanner := bufio.NewScanner(bytes.NewReader(out))
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for scanner.Scan() {
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line := strings.TrimSpace((scanner.Text()))
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if line == id {
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return true, nil
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}
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}
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return false, nil
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}
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// Pull retrieves the docker image with 'docker pull'.
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func pull(image string) error {
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var stdout, stderr bytes.Buffer
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cmd := exec.Command("docker", "pull", image)
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cmd.Stdout = &stdout
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cmd.Stderr = &stderr
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err := cmd.Run()
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out := stdout.String()
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// TODO(mpl): if it turns out docker respects conventions and the
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// "Authentication is required" message does come from stderr, then quit
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// checking stdout.
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if err != nil || stderr.Len() != 0 || strings.Contains(out, "Authentication is required") {
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return fmt.Errorf("docker pull failed: stdout: %s, stderr: %s, err: %v", out, stderr.String(), err)
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}
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return nil
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}
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