1. docker
  2. Commit 354c241041ec67d4c500cccfda476dc73435d38e
Browse code

builder: implement ref checker

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
Signed-off-by: Tibor Vass <tibor@docker.com>

Tonis Tiigi authored on 2018/09/01 10:28:25
Showing 3 changed files
builder/builder-next/adapters/snapshot/snapshot.go
History View file @ 354c241
... ... 
@@ -110,6 +110,10 @@ func (s *snapshotter) chainID(key string) (layer.ChainID, bool) {
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 	return "", false
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 }
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+func (s *snapshotter) GetLayer(key string) (layer.Layer, error) {
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+	return s.getLayer(key, true)
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+}
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+
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 func (s *snapshotter) getLayer(key string, withCommitted bool) (layer.Layer, error) {
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 	s.mu.Lock()
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 	l, ok := s.refs[key]
builder/builder-next/controller.go
History View file @ 354c241
... ... 
@@ -9,6 +9,7 @@ import (
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 	"github.com/docker/docker/builder/builder-next/adapters/containerimage"
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 	"github.com/docker/docker/builder/builder-next/adapters/snapshot"
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 	containerimageexp "github.com/docker/docker/builder/builder-next/exporter"
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+	"github.com/docker/docker/builder/builder-next/imagerefchecker"
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 	mobyworker "github.com/docker/docker/builder/builder-next/worker"
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 	"github.com/docker/docker/daemon/graphdriver"
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 	"github.com/moby/buildkit/cache"
... ... 
@@ -69,11 +70,20 @@ func newController(rt http.RoundTripper, opt Opt) (*control.Controller, error) {
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 		MetadataStore: md,
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 	})
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+	layerGetter, ok := sbase.(imagerefchecker.LayerGetter)
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+	if !ok {
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+		return nil, errors.Errorf("snapshotter does not implement layergetter")
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+	}
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+
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+	refChecker := imagerefchecker.New(imagerefchecker.Opt{
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+		ImageStore:  dist.ImageStore,
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+		LayerGetter: layerGetter,
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+	})
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+
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 	cm, err := cache.NewManager(cache.ManagerOpt{
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-		Snapshotter:   snapshotter,
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-		MetadataStore: md,
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-		// TODO: implement PruneRefChecker to correctly mark cache objects as "Shared"
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-		PruneRefChecker: nil,
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+		Snapshotter:     snapshotter,
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+		MetadataStore:   md,
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+		PruneRefChecker: refChecker,
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 	})
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 	if err != nil {
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 		return nil, err
builder/builder-next/imagerefchecker/checker.go
History View file @ 354c241
80 89 
new file mode 100644
... ... 
@@ -0,0 +1,96 @@
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+package imagerefchecker
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+
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+import (
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+	"sync"
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+
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+	"github.com/docker/docker/image"
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+	"github.com/docker/docker/layer"
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+	"github.com/moby/buildkit/cache"
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+)
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+
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+// LayerGetter abstracts away the snapshotter
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+type LayerGetter interface {
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+	GetLayer(string) (layer.Layer, error)
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+}
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+
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+// Opt represents the options needed to create a refchecker
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+type Opt struct {
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+	LayerGetter LayerGetter
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+	ImageStore  image.Store
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+}
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+
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+// New creates new image reference checker that can be used to see if a reference
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+// is being used by any of the images in the image store
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+func New(opt Opt) cache.ExternalRefCheckerFunc {
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+	return func() (cache.ExternalRefChecker, error) {
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+		return &checker{opt: opt, layers: lchain{}, cache: map[string]bool{}}, nil
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+	}
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+}
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+
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+type lchain map[layer.DiffID]lchain
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+
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+func (c lchain) add(ids []layer.DiffID) {
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+	if len(ids) == 0 {
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+		return
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+	}
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+	id := ids[0]
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+	ch, ok := c[id]
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+	if !ok {
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+		ch = lchain{}
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+		c[id] = ch
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+	}
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+	ch.add(ids[1:])
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+}
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+
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+func (c lchain) has(ids []layer.DiffID) bool {
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+	if len(ids) == 0 {
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+		return true
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+	}
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+	ch, ok := c[ids[0]]
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+	return ok && ch.has(ids[1:])
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+}
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+
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+type checker struct {
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+	opt    Opt
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+	once   sync.Once
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+	layers lchain
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+	cache  map[string]bool
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+}
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+
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+func (c *checker) Exists(key string) bool {
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+	if c.opt.ImageStore == nil {
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+		return false
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+	}
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+
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+	c.once.Do(c.init)
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+
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+	if b, ok := c.cache[key]; ok {
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+		return b
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+	}
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+
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+	l, err := c.opt.LayerGetter.GetLayer(key)
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+	if err != nil || l == nil {
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+		c.cache[key] = false
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+		return false
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+	}
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+
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+	ok := c.layers.has(diffIDs(l))
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+	c.cache[key] = ok
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+	return ok
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+}
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+
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+func (c *checker) init() {
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+	imgs := c.opt.ImageStore.Map()
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+
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+	for _, img := range imgs {
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+		c.layers.add(img.RootFS.DiffIDs)
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+	}
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+}
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+
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+func diffIDs(l layer.Layer) []layer.DiffID {
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+	p := l.Parent()
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+	if p == nil {
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+		return []layer.DiffID{l.DiffID()}
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+	}
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+	return append(diffIDs(p), l.DiffID())
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+}