DelegateLayerHandler now uses http method in url generation

storage/cloudfrontlayerhandler.go

@@ -19,6 +19,7 @@ import (
 type cloudFrontLayerHandler struct {
 	cloudfront           *cloudfront.CloudFront
 	delegateLayerHandler *delegateLayerHandler
+	duration             time.Duration
 }
 
 var _ LayerHandler = &cloudFrontLayerHandler{}
@@ -74,13 +75,28 @@ func newCloudFrontLayerHandler(storageDriver storagedriver.StorageDriver, option
 
 	cf := cloudfront.New(baseURL, privateKey, keypairID)
 
-	return &cloudFrontLayerHandler{cloudfront: cf, delegateLayerHandler: dlh}, nil
+	duration := 20 * time.Minute
+	d, ok := options["duration"]
+	if ok {
+		switch d := d.(type) {
+		case time.Duration:
+			duration = d
+		case string:
+			dur, err := time.ParseDuration(d)
+			if err != nil {
+				return nil, fmt.Errorf("Invalid duration: %s", err)
+			}
+			duration = dur
+		}
+	}
+
+	return &cloudFrontLayerHandler{cloudfront: cf, delegateLayerHandler: dlh, duration: duration}, nil
 }
 
 // Resolve returns an http.Handler which can serve the contents of the given
 // Layer, or an error if not supported by the storagedriver.
 func (lh *cloudFrontLayerHandler) Resolve(layer Layer) (http.Handler, error) {
-	layerURLStr, err := lh.delegateLayerHandler.urlFor(layer)
+	layerURLStr, err := lh.delegateLayerHandler.urlFor(layer, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -90,7 +106,7 @@ func (lh *cloudFrontLayerHandler) Resolve(layer Layer) (http.Handler, error) {
 		return nil, err
 	}
 
-	cfURL, err := lh.cloudfront.CannedSignedURL(layerURL.Path, "", time.Now().Add(20*time.Minute))
+	cfURL, err := lh.cloudfront.CannedSignedURL(layerURL.Path, "", time.Now().Add(lh.duration))
 	if err != nil {
 		return nil, err
 	}

storage/delegatelayerhandler.go

@@ -41,19 +41,30 @@ func newDelegateLayerHandler(storageDriver storagedriver.StorageDriver, options
 // Resolve returns an http.Handler which can serve the contents of the given
 // Layer, or an error if not supported by the storagedriver.
 func (lh *delegateLayerHandler) Resolve(layer Layer) (http.Handler, error) {
-	layerURL, err := lh.urlFor(layer)
+	// TODO(bbland): This is just a sanity check to ensure that the
+	// storagedriver supports url generation. It would be nice if we didn't have
+	// to do this twice for non-GET requests.
+	layerURL, err := lh.urlFor(layer, map[string]interface{}{"method": "GET"})
 	if err != nil {
 		return nil, err
 	}
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "GET" {
+			layerURL, err = lh.urlFor(layer, map[string]interface{}{"method": r.Method})
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		}
+
 		http.Redirect(w, r, layerURL, http.StatusTemporaryRedirect)
 	}), nil
 }
 
 // urlFor returns a download URL for the given layer, or the empty string if
 // unsupported.
-func (lh *delegateLayerHandler) urlFor(layer Layer) (string, error) {
+func (lh *delegateLayerHandler) urlFor(layer Layer, options map[string]interface{}) (string, error) {
 	// Crack open the layer to get at the layerStore
 	layerRd, ok := layer.(*layerReader)
 	if !ok {
@@ -64,7 +75,12 @@ func (lh *delegateLayerHandler) urlFor(layer Layer) (string, error) {
 		return "", fmt.Errorf("unsupported layer type: cannot resolve blob path: %v", layer)
 	}
 
-	layerURL, err := lh.storageDriver.URLFor(layerRd.path, map[string]interface{}{"expiry": time.Now().Add(lh.duration)})
+	if options == nil {
+		options = make(map[string]interface{})
+	}
+	options["expiry"] = time.Now().Add(lh.duration)
+
+	layerURL, err := lh.storageDriver.URLFor(layerRd.path, options)
 	if err != nil {
 		return "", err
 	}