Move notifications package to distribution

Since the notifications package is now decoupled from storage, we are moving it
to the root package.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

notifications/bridge.go

@@ -0,0 +1,155 @@
+package notifications
+
+import (
+	"net/http"
+	"time"
+
+	"code.google.com/p/go-uuid/uuid"
+	"github.com/docker/distribution"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/distribution/manifest"
+)
+
+type bridge struct {
+	ub      URLBuilder
+	actor   ActorRecord
+	source  SourceRecord
+	request RequestRecord
+	sink    Sink
+}
+
+var _ Listener = &bridge{}
+
+// URLBuilder defines a subset of url builder to be used by the event listener.
+type URLBuilder interface {
+	BuildManifestURL(name, tag string) (string, error)
+	BuildBlobURL(name string, dgst digest.Digest) (string, error)
+}
+
+// NewBridge returns a notification listener that writes records to sink,
+// using the actor and source. Any urls populated in the events created by
+// this bridge will be created using the URLBuilder.
+// TODO(stevvooe): Update this to simply take a context.Context object.
+func NewBridge(ub URLBuilder, source SourceRecord, actor ActorRecord, request RequestRecord, sink Sink) Listener {
+	return &bridge{
+		ub:      ub,
+		actor:   actor,
+		source:  source,
+		request: request,
+		sink:    sink,
+	}
+}
+
+// NewRequestRecord builds a RequestRecord for use in NewBridge from an
+// http.Request, associating it with a request id.
+func NewRequestRecord(id string, r *http.Request) RequestRecord {
+	return RequestRecord{
+		ID:        id,
+		Addr:      r.RemoteAddr,
+		Host:      r.Host,
+		Method:    r.Method,
+		UserAgent: r.UserAgent(),
+	}
+}
+
+func (b *bridge) ManifestPushed(repo distribution.Repository, sm *manifest.SignedManifest) error {
+	return b.createManifestEventAndWrite(EventActionPush, repo, sm)
+}
+
+func (b *bridge) ManifestPulled(repo distribution.Repository, sm *manifest.SignedManifest) error {
+	return b.createManifestEventAndWrite(EventActionPull, repo, sm)
+}
+
+func (b *bridge) ManifestDeleted(repo distribution.Repository, sm *manifest.SignedManifest) error {
+	return b.createManifestEventAndWrite(EventActionDelete, repo, sm)
+}
+
+func (b *bridge) LayerPushed(repo distribution.Repository, layer distribution.Layer) error {
+	return b.createLayerEventAndWrite(EventActionPush, repo, layer.Digest())
+}
+
+func (b *bridge) LayerPulled(repo distribution.Repository, layer distribution.Layer) error {
+	return b.createLayerEventAndWrite(EventActionPull, repo, layer.Digest())
+}
+
+func (b *bridge) LayerDeleted(repo distribution.Repository, layer distribution.Layer) error {
+	return b.createLayerEventAndWrite(EventActionDelete, repo, layer.Digest())
+}
+
+func (b *bridge) createManifestEventAndWrite(action string, repo distribution.Repository, sm *manifest.SignedManifest) error {
+	event, err := b.createManifestEvent(action, repo, sm)
+	if err != nil {
+		return err
+	}
+
+	return b.sink.Write(*event)
+}
+
+func (b *bridge) createManifestEvent(action string, repo distribution.Repository, sm *manifest.SignedManifest) (*Event, error) {
+	event := b.createEvent(action)
+	event.Target.Type = EventTargetTypeManifest
+	event.Target.Name = repo.Name()
+	event.Target.Tag = sm.Tag
+
+	p, err := sm.Payload()
+	if err != nil {
+		return nil, err
+	}
+
+	event.Target.Digest, err = digest.FromBytes(p)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(stevvooe): Currently, the is the "tag" url: once the digest url is
+	// implemented, this should be replaced.
+	event.Target.URL, err = b.ub.BuildManifestURL(sm.Name, sm.Tag)
+	if err != nil {
+		return nil, err
+	}
+
+	return event, nil
+}
+
+func (b *bridge) createLayerEventAndWrite(action string, repo distribution.Repository, dgst digest.Digest) error {
+	event, err := b.createLayerEvent(action, repo, dgst)
+	if err != nil {
+		return err
+	}
+
+	return b.sink.Write(*event)
+}
+
+func (b *bridge) createLayerEvent(action string, repo distribution.Repository, dgst digest.Digest) (*Event, error) {
+	event := b.createEvent(action)
+	event.Target.Type = EventTargetTypeBlob
+	event.Target.Name = repo.Name()
+	event.Target.Digest = dgst
+
+	var err error
+	event.Target.URL, err = b.ub.BuildBlobURL(repo.Name(), dgst)
+	if err != nil {
+		return nil, err
+	}
+
+	return event, nil
+}
+
+// createEvent creates an event with actor and source populated.
+func (b *bridge) createEvent(action string) *Event {
+	event := createEvent(action)
+	event.Source = b.source
+	event.Actor = b.actor
+	event.Request = b.request
+
+	return event
+}
+
+// createEvent returns a new event, timestamped, with the specified action.
+func createEvent(action string) *Event {
+	return &Event{
+		ID:        uuid.New(),
+		Timestamp: time.Now(),
+		Action:    action,
+	}
+}