Make gce endpoint strings configurable.

This will allow packages who import this to configure the endpoints to something like https://mydomain.com/compute/v1.
These endpoints are only used for SelfLink().

pkg/cloud/utils.go

@@ -24,10 +24,10 @@ import (
 	"github.com/GoogleCloudPlatform/k8s-cloud-provider/pkg/cloud/meta"
 )
 
-const (
-	gaPrefix    = "https://www.googleapis.com/compute/v1"
-	alphaPrefix = "https://www.googleapis.com/compute/alpha"
-	betaPrefix  = "https://www.googleapis.com/compute/beta"
+var (
+	GAPrefix    = "https://www.googleapis.com/compute/v1"
+	AlphaPrefix = "https://www.googleapis.com/compute/alpha"
+	BetaPrefix  = "https://www.googleapis.com/compute/beta"
 )
 
 // ResourceID identifies a GCE resource as parsed from compute resource URL.
@@ -191,11 +191,11 @@ func SelfLink(ver meta.Version, project, resource string, key *meta.Key) string
 	var prefix string
 	switch ver {
 	case meta.VersionAlpha:
-		prefix = alphaPrefix
+		prefix = AlphaPrefix
 	case meta.VersionBeta:
-		prefix = betaPrefix
+		prefix = BetaPrefix
 	case meta.VersionGA:
-		prefix = gaPrefix
+		prefix = GAPrefix
 	default:
 		prefix = "invalid-prefix"
 	}