cachemanager: check pulled snapshot

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

cache/manager.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 
 	"github.com/boltdb/bolt"
+	cdsnapshot "github.com/containerd/containerd/snapshot"
 	"github.com/pkg/errors"
 	"github.com/tonistiigi/buildkit_poc/snapshot"
 )
@@ -101,10 +102,34 @@ func (cm *cacheManager) Close() error {
 func (cm *cacheManager) Get(id string) (ImmutableRef, error) {
 	cm.mu.Lock()
 	defer cm.mu.Unlock()
+	return cm.get(id)
+}
+func (cm *cacheManager) get(id string) (ImmutableRef, error) {
 	rec, ok := cm.records[id]
 	if !ok {
-		// TODO: lazy-load from Snapshotter
-		return nil, errors.Wrapf(errNotFound, "%s not found", id)
+		info, err := cm.Snapshotter.Stat(context.TODO(), id)
+		if err != nil {
+			return nil, err
+		}
+		if info.Kind != cdsnapshot.KindCommitted {
+			return nil, errors.Wrapf(errInvalid, "can't lazy load active %s", id)
+		}
+
+		var parent ImmutableRef
+		if info.Parent != "" {
+			parent, err = cm.get(info.Parent)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		rec = &cacheRecord{
+			id:     id,
+			cm:     cm,
+			refs:   make(map[*cacheRef]struct{}),
+			parent: parent,
+		}
+		cm.records[id] = rec // TODO: store to db
 	}
 
 	rec.mu.Lock()

cache/refs.go

@@ -39,6 +39,8 @@ type cacheRecord struct {
 	id        string
 	cm        *cacheManager
 	parent    ImmutableRef
+	view      string
+	viewMount []mount.Mount
 }
 
 // hold manager lock before calling
@@ -62,6 +64,17 @@ func (sr *cacheRef) Mount() ([]mount.Mount, error) {
 			return nil, errors.Wrapf(err, "failed to mount %s", sr.id)
 		}
 		return m, nil
+	} else {
+		if sr.viewMount == nil { // TODO: handle this better
+			sr.view = generateID()
+			m, err := sr.cm.Snapshotter.View(context.TODO(), sr.view, sr.id)
+			if err != nil {
+				sr.view = ""
+				return nil, errors.Wrapf(err, "failed to mount %s", sr.id)
+			}
+			sr.viewMount = m
+		}
+		return sr.viewMount, nil
 	}
 
 	return nil, errors.New("snapshot mount not implemented")
@@ -83,6 +96,14 @@ func (sr *cacheRef) release() error {
 			return err
 		}
 	}
+	if sr.viewMount != nil {
+		if err := sr.cm.Snapshotter.Remove(context.TODO(), sr.view); err != nil {
+			return err
+		}
+		sr.view = ""
+		sr.viewMount = nil
+	}
+
 	delete(sr.refs, sr)
 	sr.frozen = false
 

control/control_test.go

@@ -15,21 +15,23 @@ import (
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/rootfs"
-	"github.com/containerd/containerd/snapshot"
+	cdsnapshot "github.com/containerd/containerd/snapshot"
 	"github.com/containerd/containerd/snapshot/naive"
 	digest "github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/tonistiigi/buildkit_poc/cache"
+	"github.com/tonistiigi/buildkit_poc/snapshot"
 	"github.com/tonistiigi/buildkit_poc/source"
 	"github.com/tonistiigi/buildkit_poc/source/containerimage"
 )
 
 func TestControl(t *testing.T) {
+	// this should be an example or e2e test
 	tmpdir, err := ioutil.TempDir("", "controltest")
 	assert.NoError(t, err)
-	// defer os.RemoveAll(tmpdir)
+	defer os.RemoveAll(tmpdir)
 
 	cd, err := localContainerd(tmpdir)
 	assert.NoError(t, err)
@@ -46,7 +48,7 @@ func TestControl(t *testing.T) {
 		Snapshotter:   cd.Snapshotter,
 		ContentStore:  cd.ContentStore,
 		Applier:       cd.Applier,
-		Accessor:     cm,
+		CacheAccessor: cm,
 	})
 	assert.NoError(t, err)
 
@@ -58,11 +60,33 @@ func TestControl(t *testing.T) {
 	snap, err := sm.Pull(context.TODO(), img)
 	assert.NoError(t, err)
 
-	_ = snap
+	mounts, err := snap.Mount()
+	assert.NoError(t, err)
+
+	lm := snapshot.LocalMounter(mounts)
+
+	target, err := lm.Mount()
+	assert.NoError(t, err)
+
+	f, err := os.Open(target)
+	assert.NoError(t, err)
+
+	names, err := f.Readdirnames(-1)
+	assert.NoError(t, err)
+	assert.True(t, len(names) > 10)
+
+	err = f.Close()
+	assert.NoError(t, err)
+
+	lm.Unmount()
+	assert.NoError(t, err)
+
+	err = snap.Release()
+	assert.NoError(t, err)
 }
 
 type containerd struct {
-	Snapshotter  snapshot.Snapshotter
+	Snapshotter  cdsnapshot.Snapshotter
 	ContentStore content.Store
 	Applier      rootfs.Applier
 }
@@ -149,15 +173,3 @@ func (rc *readCounter) Read(p []byte) (n int, err error) {
 	rc.c += int64(n)
 	return
 }
-
-// req := &diffapi.ApplyRequest{
-// 	Diff:   fromDescriptor(diff),
-// 	Mounts: fromMounts(mounts),
-// }
-// resp, err := r.client.Apply(ctx, req)
-// if err != nil {
-// 	return ocispec.Descriptor{}, err
-// }
-// return toDescriptor(resp.Applied), nil
-
-//	Apply(context.Context, ocispec.Descriptor, []mount.Mount) (ocispec.Descriptor, error)

snapshot/snapshotter.go

@@ -4,11 +4,15 @@ import (
 	"context"
 
 	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/snapshot"
 )
 
 // Snapshotter defines interface that any snapshot implementation should satisfy
 type Snapshotter interface {
+	Stat(ctx context.Context, key string) (snapshot.Info, error)
 	Prepare(ctx context.Context, key, parent string) ([]mount.Mount, error)
 	Mounts(ctx context.Context, key string) ([]mount.Mount, error)
 	Commit(ctx context.Context, name, key string) error
+	View(ctx context.Context, key, parent string) ([]mount.Mount, error)
+	Remove(ctx context.Context, key string) error
 }

source/containerimage/pull.go

@@ -24,7 +24,7 @@ type SourceOpt struct {
 	Snapshotter   snapshot.Snapshotter
 	ContentStore  content.Store
 	Applier       rootfs.Applier
-	Accessor     cache.Accessor
+	CacheAccessor cache.Accessor
 }
 
 type imageSource struct {
@@ -64,6 +64,9 @@ func (is *imageSource) Pull(ctx context.Context, id source.Identifier) (cache.Im
 		return nil, err
 	}
 
+	// TODO: need a wrapper snapshot interface that combines content
+	// and snapshots as 1) buildkit shouldn't have a dependency on contentstore
+	// or 2) cachemanager should manage the contentstore
 	handlers := []images.Handler{
 		remotes.FetchHandler(is.ContentStore, fetcher),
 		images.ChildrenHandler(is.ContentStore),
@@ -72,24 +75,25 @@ func (is *imageSource) Pull(ctx context.Context, id source.Identifier) (cache.Im
 		return nil, err
 	}
 
-	if err := is.unpack(ctx, desc); err != nil {
+	chainid, err := is.unpack(ctx, desc)
+	if err != nil {
 		return nil, err
 	}
-	return nil, nil
+
+	return is.CacheAccessor.Get(chainid)
 }
 
-func (is *imageSource) unpack(ctx context.Context, desc ocispec.Descriptor) error {
+func (is *imageSource) unpack(ctx context.Context, desc ocispec.Descriptor) (string, error) {
 	layers, err := getLayers(ctx, is.ContentStore, desc)
 	if err != nil {
-		return err
+		return "", err
 	}
 
-	chainid, err := rootfs.ApplyLayers(ctx, layers, is.Snapshotter, is.Applier)
+	chainID, err := rootfs.ApplyLayers(ctx, layers, is.Snapshotter, is.Applier)
 	if err != nil {
-		return err
+		return "", err
 	}
-	_ = chainid
-	return nil
+	return string(chainID), nil
 }
 
 func getLayers(ctx context.Context, provider content.Provider, desc ocispec.Descriptor) ([]rootfs.Layer, error) {