V2 registry fallback

graph/push.go

@@ -262,6 +262,9 @@ func (s *TagStore) pushV2Repository(r *registry.Session, eng *engine.Engine, out
 
 	endpoint, err := r.V2RegistryEndpoint(repoInfo.Index)
 	if err != nil {
+		if err == registry.ErrEndpointNotFound {
+			return err
+		}
 		return fmt.Errorf("error getting registry endpoint: %s", err)
 	}
 	auth, err := r.GetV2Authorization(endpoint, repoInfo.RemoteName, false)
@@ -378,6 +381,12 @@ func (s *TagStore) CmdPush(job *engine.Job) engine.Status {
 	job.GetenvJson("authConfig", authConfig)
 	job.GetenvJson("metaHeaders", &metaHeaders)
 
+	// Set a header so remotes can identify the command being carried out. If
+	// present, the remote may act on the field but this is mostly advisory.
+	metaHeaders["Docker-Command"] = []string{"push"}
+
+	repoInfo.Index.Headers = metaHeaders
+
 	if _, err := s.poolAdd("push", repoInfo.LocalName); err != nil {
 		return job.Error(err)
 	}
@@ -403,9 +412,12 @@ func (s *TagStore) CmdPush(job *engine.Job) engine.Status {
 		if err == nil {
 			return engine.StatusOK
 		}
-
-		// error out, no fallback to V1
-		return job.Error(err)
+		if err != registry.ErrEndpointNotFound {
+			// error out, no fallback to V1
+			return job.Error(err)
+		} else {
+			log.Debugf("Skipping V2 registry: endpoint not available")
+		}
 	}
 
 	if err != nil {

registry/endpoint.go

@@ -2,6 +2,7 @@ package registry
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -11,11 +12,14 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/registry/v2"
+	"github.com/docker/docker/utils"
 )
 
 // for mocking in unit tests
 var lookupIP = net.LookupIP
 
+var ErrEndpointNotFound = errors.New("endpoint not found")
+
 // scans string for api version in the URL path. returns the trimmed address, if version found, string and API version.
 func scanForAPIVersion(address string) (string, APIVersion) {
 	var (
@@ -43,7 +47,7 @@ func scanForAPIVersion(address string) (string, APIVersion) {
 // NewEndpoint parses the given address to return a registry endpoint.
 func NewEndpoint(index *IndexInfo) (*Endpoint, error) {
 	// *TODO: Allow per-registry configuration of endpoints.
-	endpoint, err := newEndpoint(index.GetAuthConfigKey(), index.Secure)
+	endpoint, err := newEndpoint(index.GetAuthConfigKey(), index.Secure, index.Headers)
 	if err != nil {
 		return nil, err
 	}
@@ -60,6 +64,9 @@ func validateEndpoint(endpoint *Endpoint) error {
 	// Try HTTPS ping to registry
 	endpoint.URL.Scheme = "https"
 	if _, err := endpoint.Ping(); err != nil {
+		if err == ErrEndpointNotFound {
+			return err
+		}
 		if endpoint.IsSecure {
 			// If registry is secure and HTTPS failed, show user the error and tell them about `--insecure-registry`
 			// in case that's what they need. DO NOT accept unknown CA certificates, and DO NOT fallback to HTTP.
@@ -74,14 +81,17 @@ func validateEndpoint(endpoint *Endpoint) error {
 		if _, err2 = endpoint.Ping(); err2 == nil {
 			return nil
 		}
+		if err2 == ErrEndpointNotFound {
+			return err2
+		}
 
 		return fmt.Errorf("invalid registry endpoint %q. HTTPS attempt: %v. HTTP attempt: %v", endpoint, err, err2)
 	}
 
 	return nil
 }
 
-func newEndpoint(address string, secure bool) (*Endpoint, error) {
+func newEndpoint(address string, secure bool, headers map[string][]string) (*Endpoint, error) {
 	var (
 		endpoint       = new(Endpoint)
 		trimmedAddress string
@@ -98,6 +108,7 @@ func newEndpoint(address string, secure bool) (*Endpoint, error) {
 		return nil, err
 	}
 	endpoint.IsSecure = secure
+	endpoint.ReqFactory = HTTPRequestFactory(headers)
 	return endpoint, nil
 }
 
@@ -112,6 +123,7 @@ type Endpoint struct {
 	IsSecure       bool
 	AuthChallenges []*AuthorizationChallenge
 	URLBuilder     *v2.URLBuilder
+	ReqFactory     *utils.HTTPRequestFactory
 }
 
 // Get the formated URL for the root of this registry Endpoint
@@ -168,7 +180,7 @@ func (e *Endpoint) pingV1() (RegistryInfo, error) {
 		return RegistryInfo{Standalone: false}, nil
 	}
 
-	req, err := http.NewRequest("GET", e.Path("_ping"), nil)
+	req, err := e.ReqFactory.NewRequest("GET", e.Path("_ping"), nil)
 	if err != nil {
 		return RegistryInfo{Standalone: false}, err
 	}
@@ -216,7 +228,7 @@ func (e *Endpoint) pingV1() (RegistryInfo, error) {
 func (e *Endpoint) pingV2() (RegistryInfo, error) {
 	log.Debugf("attempting v2 ping for registry endpoint %s", e)
 
-	req, err := http.NewRequest("GET", e.Path(""), nil)
+	req, err := e.ReqFactory.NewRequest("GET", e.Path(""), nil)
 	if err != nil {
 		return RegistryInfo{}, err
 	}
@@ -240,5 +252,9 @@ func (e *Endpoint) pingV2() (RegistryInfo, error) {
 		return RegistryInfo{}, nil
 	}
 
+	if resp.StatusCode == http.StatusNotFound {
+		return RegistryInfo{}, ErrEndpointNotFound
+	}
+
 	return RegistryInfo{}, fmt.Errorf("v2 registry endpoint returned status %d: %q", resp.StatusCode, http.StatusText(resp.StatusCode))
 }

registry/session_v2.go

@@ -22,7 +22,7 @@ func getV2Builder(e *Endpoint) *v2.URLBuilder {
 func (r *Session) V2RegistryEndpoint(index *IndexInfo) (ep *Endpoint, err error) {
 	// TODO check if should use Mirror
 	if index.Official {
-		ep, err = newEndpoint(REGISTRYSERVER, true)
+		ep, err = newEndpoint(REGISTRYSERVER, index.Secure, index.Headers)
 		if err != nil {
 			return
 		}
@@ -222,6 +222,12 @@ func (r *Session) PutV2ImageBlob(ep *Endpoint, imageName, sumType, sumStr string
 	if err != nil {
 		return err
 	}
+	if res.StatusCode != 202 {
+		if res.StatusCode == 401 {
+			return errLoginRequired
+		}
+		return utils.NewHTTPRequestError(fmt.Sprintf("Server error: %d trying to push %s blob", res.StatusCode, imageName), res)
+	}
 	location := res.Header.Get("Location")
 
 	method := "PUT"

registry/types.go

@@ -98,6 +98,7 @@ type IndexInfo struct {
 	Mirrors  []string
 	Secure   bool
 	Official bool
+	Headers  map[string][]string
 }
 
 type RepositoryInfo struct {