Use request factory for registry ping

Currently when the registry ping is sent, it creates the request directly from http.NewRequest instead of from the http request factory. The request factory adds useful header information such as user agent which is needed by the registry.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

registry/endpoint.go

@@ -11,6 +11,7 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/registry/v2"
+	"github.com/docker/docker/utils"
 )
 
 // for mocking in unit tests
@@ -133,24 +134,25 @@ func (e *Endpoint) Path(path string) string {
 
 func (e *Endpoint) Ping() (RegistryInfo, error) {
 	// The ping logic to use is determined by the registry endpoint version.
+	factory := HTTPRequestFactory(nil)
 	switch e.Version {
 	case APIVersion1:
-		return e.pingV1()
+		return e.pingV1(factory)
 	case APIVersion2:
-		return e.pingV2()
+		return e.pingV2(factory)
 	}
 
 	// APIVersionUnknown
 	// We should try v2 first...
 	e.Version = APIVersion2
-	regInfo, errV2 := e.pingV2()
+	regInfo, errV2 := e.pingV2(factory)
 	if errV2 == nil {
 		return regInfo, nil
 	}
 
 	// ... then fallback to v1.
 	e.Version = APIVersion1
-	regInfo, errV1 := e.pingV1()
+	regInfo, errV1 := e.pingV1(factory)
 	if errV1 == nil {
 		return regInfo, nil
 	}
@@ -159,7 +161,7 @@ func (e *Endpoint) Ping() (RegistryInfo, error) {
 	return RegistryInfo{}, fmt.Errorf("unable to ping registry endpoint %s\nv2 ping attempt failed with error: %s\n v1 ping attempt failed with error: %s", e, errV2, errV1)
 }
 
-func (e *Endpoint) pingV1() (RegistryInfo, error) {
+func (e *Endpoint) pingV1(factory *utils.HTTPRequestFactory) (RegistryInfo, error) {
 	log.Debugf("attempting v1 ping for registry endpoint %s", e)
 
 	if e.String() == IndexServerAddress() {
@@ -168,7 +170,7 @@ func (e *Endpoint) pingV1() (RegistryInfo, error) {
 		return RegistryInfo{Standalone: false}, nil
 	}
 
-	req, err := http.NewRequest("GET", e.Path("_ping"), nil)
+	req, err := factory.NewRequest("GET", e.Path("_ping"), nil)
 	if err != nil {
 		return RegistryInfo{Standalone: false}, err
 	}
@@ -213,10 +215,10 @@ func (e *Endpoint) pingV1() (RegistryInfo, error) {
 	return info, nil
 }
 
-func (e *Endpoint) pingV2() (RegistryInfo, error) {
+func (e *Endpoint) pingV2(factory *utils.HTTPRequestFactory) (RegistryInfo, error) {
 	log.Debugf("attempting v2 ping for registry endpoint %s", e)
 
-	req, err := http.NewRequest("GET", e.Path(""), nil)
+	req, err := factory.NewRequest("GET", e.Path(""), nil)
 	if err != nil {
 		return RegistryInfo{}, err
 	}