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package checkpoint
import (
"context"
"io/ioutil"
"os"
"path/filepath"
"github.com/containers/podman/v2/libpod"
"github.com/containers/podman/v2/libpod/image"
"github.com/containers/podman/v2/pkg/errorhandling"
"github.com/containers/podman/v2/pkg/util"
"github.com/containers/storage/pkg/archive"
jsoniter "github.com/json-iterator/go"
spec "github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// Prefixing the checkpoint/restore related functions with 'cr'
// crImportFromJSON imports the JSON files stored in the exported
// checkpoint tarball
func crImportFromJSON(filePath string, v interface{}) error {
content, err := ioutil.ReadFile(filePath)
if err != nil {
return errors.Wrap(err, "failed to read container definition for restore")
}
json := jsoniter.ConfigCompatibleWithStandardLibrary
if err = json.Unmarshal(content, v); err != nil {
return errors.Wrapf(err, "failed to unmarshal container definition %s for restore", filePath)
}
return nil
}
// CRImportCheckpoint it the function which imports the information
// from checkpoint tarball and re-creates the container from that information
func CRImportCheckpoint(ctx context.Context, runtime *libpod.Runtime, input string, name string) ([]*libpod.Container, error) {
// First get the container definition from the
// tarball to a temporary directory
archiveFile, err := os.Open(input)
if err != nil {
return nil, errors.Wrap(err, "failed to open checkpoint archive for import")
}
defer errorhandling.CloseQuiet(archiveFile)
options := &archive.TarOptions{
// Here we only need the files config.dump and spec.dump
ExcludePatterns: []string{
"checkpoint",
"artifacts",
"ctr.log",
"rootfs-diff.tar",
"network.status",
"deleted.files",
},
}
dir, err := ioutil.TempDir("", "checkpoint")
if err != nil {
return nil, err
}
defer func() {
if err := os.RemoveAll(dir); err != nil {
logrus.Errorf("could not recursively remove %s: %q", dir, err)
}
}()
err = archive.Untar(archiveFile, dir, options)
if err != nil {
return nil, errors.Wrapf(err, "Unpacking of checkpoint archive %s failed", input)
}
// Load spec.dump from temporary directory
dumpSpec := new(spec.Spec)
if err := crImportFromJSON(filepath.Join(dir, "spec.dump"), dumpSpec); err != nil {
return nil, err
}
// Load config.dump from temporary directory
config := new(libpod.ContainerConfig)
if err = crImportFromJSON(filepath.Join(dir, "config.dump"), config); err != nil {
return nil, err
}
// This should not happen as checkpoints with these options are not exported.
if (len(config.Dependencies) > 0) || (len(config.NamedVolumes) > 0) {
return nil, errors.Errorf("Cannot import checkpoints of containers with named volumes or dependencies")
}
ctrID := config.ID
newName := false
// Check if the restored container gets a new name
if name != "" {
config.ID = ""
config.Name = name
newName = true
}
ctrName := config.Name
// The code to load the images is copied from create.go
// In create.go this only set if '--quiet' does not exist.
writer := os.Stderr
rtc, err := runtime.GetConfig()
if err != nil {
return nil, err
}
_, err = runtime.ImageRuntime().New(ctx, config.RootfsImageName, rtc.Engine.SignaturePolicyPath, "", writer, nil, image.SigningOptions{}, nil, util.PullImageMissing)
if err != nil {
return nil, err
}
// Now create a new container from the just loaded information
container, err := runtime.RestoreContainer(ctx, dumpSpec, config)
if err != nil {
return nil, err
}
var containers []*libpod.Container
if container == nil {
return nil, nil
}
containerConfig := container.Config()
if containerConfig.Name != ctrName {
return nil, errors.Errorf("Name of restored container (%s) does not match requested name (%s)", containerConfig.Name, ctrName)
}
if !newName {
// Only check ID for a restore with the same name.
// Using -n to request a new name for the restored container, will also create a new ID
if containerConfig.ID != ctrID {
return nil, errors.Errorf("ID of restored container (%s) does not match requested ID (%s)", containerConfig.ID, ctrID)
}
}
// Check if the ExitCommand points to the correct container ID
if containerConfig.ExitCommand[len(containerConfig.ExitCommand)-1] != containerConfig.ID {
return nil, errors.Errorf("'ExitCommandID' uses ID %s instead of container ID %s", containerConfig.ExitCommand[len(containerConfig.ExitCommand)-1], containerConfig.ID)
}
containers = append(containers, container)
return containers, nil
}
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