95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
package rootfs
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import (
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"context"
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"fmt"
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"io/ioutil"
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"os"
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"github.com/containerd/containerd"
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"github.com/containerd/containerd/log"
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"github.com/containerd/containerd/snapshot"
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digest "github.com/opencontainers/go-digest"
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"github.com/pkg/errors"
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)
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var (
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initializers = map[string]initializerFunc{}
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)
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type initializerFunc func(string) error
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func InitRootFS(ctx context.Context, name string, parent digest.Digest, readonly bool, snapshotter snapshot.Snapshotter, mounter Mounter) ([]containerd.Mount, error) {
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_, err := snapshotter.Stat(ctx, name)
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if err == nil {
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return nil, errors.Errorf("rootfs already exists")
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}
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// TODO: ensure not exist error once added to snapshot package
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parentS := parent.String()
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initName := defaultInitializer
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initFn := initializers[initName]
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if initFn != nil {
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parentS, err = createInitLayer(ctx, parentS, initName, initFn, snapshotter, mounter)
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if err != nil {
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return nil, err
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}
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}
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if readonly {
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return snapshotter.View(ctx, name, parentS)
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}
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return snapshotter.Prepare(ctx, name, parentS)
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}
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func createInitLayer(ctx context.Context, parent, initName string, initFn func(string) error, snapshotter snapshot.Snapshotter, mounter Mounter) (string, error) {
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initS := fmt.Sprintf("%s %s", parent, initName)
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if _, err := snapshotter.Stat(ctx, initS); err == nil {
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return initS, nil
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}
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// TODO: ensure not exist error once added to snapshot package
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// Create tempdir
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td, err := ioutil.TempDir("", "create-init-")
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if err != nil {
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return "", err
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}
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defer os.RemoveAll(td)
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mounts, err := snapshotter.Prepare(ctx, td, parent)
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if err != nil {
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return "", err
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}
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defer func() {
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if err != nil {
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// TODO: once implemented uncomment
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//if rerr := snapshotter.Remove(ctx, td); rerr != nil {
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// log.G(ctx).Errorf("Failed to remove snapshot %s: %v", td, merr)
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//}
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}
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}()
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if err = mounter.Mount(td, mounts...); err != nil {
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return "", err
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}
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if err = initFn(td); err != nil {
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if merr := mounter.Unmount(td); merr != nil {
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log.G(ctx).Errorf("Failed to unmount %s: %v", td, merr)
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}
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return "", err
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}
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if err = mounter.Unmount(td); err != nil {
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return "", err
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}
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if err := snapshotter.Commit(ctx, initS, td); err != nil {
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return "", err
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}
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return initS, nil
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}
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