package client import ( "bytes" "io" "io/ioutil" "github.com/docker/docker-registry/storage" log "github.com/Sirupsen/logrus" ) // simultaneousLayerPushWindow is the size of the parallel layer push window. // A layer may not be pushed until the layer preceeding it by the length of the // push window has been successfully pushed. const simultaneousLayerPushWindow = 4 type pushFunction func(fsLayer storage.FSLayer) error // Push implements a client push workflow for the image defined by the given // name and tag pair, using the given ObjectStore for local manifest and layer // storage func Push(c Client, objectStore ObjectStore, name, tag string) error { manifest, err := objectStore.Manifest(name, tag) if err != nil { log.WithFields(log.Fields{ "error": err, "name": name, "tag": tag, }).Info("No image found") return err } errChans := make([]chan error, len(manifest.FSLayers)) for i := range manifest.FSLayers { errChans[i] = make(chan error) } cancelCh := make(chan struct{}) // Iterate over each layer in the manifest, simultaneously pushing no more // than simultaneousLayerPushWindow layers at a time. If an error is // received from a layer push, we abort the push. for i := 0; i < len(manifest.FSLayers)+simultaneousLayerPushWindow; i++ { dependentLayer := i - simultaneousLayerPushWindow if dependentLayer >= 0 { err := <-errChans[dependentLayer] if err != nil { log.WithField("error", err).Warn("Push aborted") close(cancelCh) return err } } if i < len(manifest.FSLayers) { go func(i int) { select { case errChans[i] <- pushLayer(c, objectStore, name, manifest.FSLayers[i]): case <-cancelCh: // recv broadcast notification about cancelation } }(i) } } err = c.PutImageManifest(name, tag, manifest) if err != nil { log.WithFields(log.Fields{ "error": err, "manifest": manifest, }).Warn("Unable to upload manifest") return err } return nil } func pushLayer(c Client, objectStore ObjectStore, name string, fsLayer storage.FSLayer) error { log.WithField("layer", fsLayer).Info("Pushing layer") layer, err := objectStore.Layer(fsLayer.BlobSum) if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to read local layer") return err } layerReader, err := layer.Reader() if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to read local layer") return err } defer layerReader.Close() layerBuffer := new(bytes.Buffer) layerSize, err := io.Copy(layerBuffer, layerReader) if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to read local layer") return err } length, err := c.BlobLength(name, fsLayer.BlobSum) if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to check existence of remote layer") return err } if length >= 0 { log.WithField("layer", fsLayer).Info("Layer already exists") return nil } location, err := c.InitiateBlobUpload(name) if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to upload layer") return err } err = c.UploadBlob(location, ioutil.NopCloser(layerBuffer), int(layerSize), fsLayer.BlobSum) if err != nil { log.WithFields(log.Fields{ "error": err, "layer": fsLayer, }).Warn("Unable to upload layer") return err } return nil }