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Merge pull request #2962 from ostenbom/snapshots-docs

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Update snapshots docs with garbage collector label
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Phil Estes 2019-01-29 20:50:40 +00:00 committed by GitHub
commit 77d7b01233
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1 changed files with 11 additions and 9 deletions
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20
snapshots/snapshotter.go
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@ -160,9 +160,13 @@ func (u *Usage) Add(other Usage) {
// layerPath, tmpDir := getLayerPath(), mkTmpDir() // just a path to layer tar file.
//
// We start by using a Snapshotter to Prepare a new snapshot transaction, using a
// key and descending from the empty parent "":
// key and descending from the empty parent "". To prevent our layer from being
// garbage collected during unpacking, we add the `containerd.io/gc.root` label:
//
// mounts, err := snapshotter.Prepare(ctx, key, "")
// noGcOpt := snapshotter.WithLabels(map[string]string{
// "containerd.io/gc.root": time.Now().UTC().Format(time.RFC3339),
// })
// mounts, err := snapshotter.Prepare(ctx, key, "", noGcOpt)
// if err != nil { ... }
//
// We get back a list of mounts from Snapshotter.Prepare, with the key identifying
@ -191,15 +195,13 @@ func (u *Usage) Add(other Usage) {
//
// Now that we've verified and unpacked our layer, we commit the active
// snapshot to a name. For this example, we are just going to use the layer
// digest, but in practice, this will probably be the ChainID:
// digest, but in practice, this will probably be the ChainID. This also removes
// the active snapshot:
//
// if err := snapshotter.Commit(ctx, digest.String(), key); err != nil { ... }
// if err := snapshotter.Commit(ctx, digest.String(), key, noGcOpt); err != nil { ... }
//
// Now, we have a layer in the Snapshotter that can be accessed with the digest
// provided during commit. Once you have committed the snapshot, the active
// snapshot can be removed with the following:
//
// snapshotter.Remove(ctx, key)
// provided during commit.
//
// Importing the Next Layer
//
@ -207,7 +209,7 @@ func (u *Usage) Add(other Usage) {
// above except that the parent is provided as parent when calling
// Manager.Prepare, assuming a clean, unique key identifier:
//
// mounts, err := snapshotter.Prepare(ctx, key, parentDigest)
// mounts, err := snapshotter.Prepare(ctx, key, parentDigest, noGcOpt)
//
// We then mount, apply and commit, as we did above. The new snapshot will be
// based on the content of the previous one.