distribution/storage/cloudfrontlayerhandler.go
Brian Bland 17915e1b01 Adds support for content redirects for layer downloads
Includes a delegate implementation which redirects to the URL generated
by the storagedriver, and a cloudfront implementation.
Satisfies proposal #49
2015-01-08 17:01:28 -08:00

106 lines
2.9 KiB
Go

package storage
import (
"crypto/x509"
"encoding/pem"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"time"
"github.com/crowdmob/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
}
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)
return &cloudFrontLayerHandler{cloudfront: cf, delegateLayerHandler: dlh}, 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)
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(time.Minute))
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))
}