Move storage package under registry package

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

docs/storage/cloudfrontlayerhandler.go

@@ -0,0 +1,122 @@
+package storage
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/AdRoll/goamz/cloudfront"
+	"github.com/docker/distribution/storagedriver"
+)
+
+// cloudFrontLayerHandler provides an simple implementation of layerHandler that
+// constructs temporary signed CloudFront URLs from the storagedriver layer URL,
+// then issues HTTP Temporary Redirects to this CloudFront content URL.
+type cloudFrontLayerHandler struct {
+	cloudfront           *cloudfront.CloudFront
+	delegateLayerHandler *delegateLayerHandler
+	duration             time.Duration
+}
+
+var _ LayerHandler = &cloudFrontLayerHandler{}
+
+// newCloudFrontLayerHandler constructs and returns a new CloudFront
+// LayerHandler implementation.
+// Required options: baseurl, privatekey, keypairid
+func newCloudFrontLayerHandler(storageDriver storagedriver.StorageDriver, options map[string]interface{}) (LayerHandler, error) {
+	base, ok := options["baseurl"]
+	if !ok {
+		return nil, fmt.Errorf("No baseurl provided")
+	}
+	baseURL, ok := base.(string)
+	if !ok {
+		return nil, fmt.Errorf("baseurl must be a string")
+	}
+	pk, ok := options["privatekey"]
+	if !ok {
+		return nil, fmt.Errorf("No privatekey provided")
+	}
+	pkPath, ok := pk.(string)
+	if !ok {
+		return nil, fmt.Errorf("privatekey must be a string")
+	}
+	kpid, ok := options["keypairid"]
+	if !ok {
+		return nil, fmt.Errorf("No keypairid provided")
+	}
+	keypairID, ok := kpid.(string)
+	if !ok {
+		return nil, fmt.Errorf("keypairid must be a string")
+	}
+
+	pkBytes, err := ioutil.ReadFile(pkPath)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to read privatekey file: %s", err)
+	}
+
+	block, _ := pem.Decode([]byte(pkBytes))
+	if block == nil {
+		return nil, fmt.Errorf("Failed to decode private key as an rsa private key")
+	}
+	privateKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+
+	lh, err := newDelegateLayerHandler(storageDriver, options)
+	if err != nil {
+		return nil, err
+	}
+	dlh := lh.(*delegateLayerHandler)
+
+	cf := cloudfront.New(baseURL, privateKey, keypairID)
+
+	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, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	layerURL, err := url.Parse(layerURLStr)
+	if err != nil {
+		return nil, err
+	}
+
+	cfURL, err := lh.cloudfront.CannedSignedURL(layerURL.Path, "", time.Now().Add(lh.duration))
+	if err != nil {
+		return nil, err
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, cfURL, http.StatusTemporaryRedirect)
+	}), nil
+}
+
+// init registers the cloudfront layerHandler backend.
+func init() {
+	RegisterLayerHandler("cloudfront", LayerHandlerInitFunc(newCloudFrontLayerHandler))
+}