Add two constructors for authContext

This includes:
- SetupAuthContext:  Setups authContext with new authContext fields.
- NewAuthContext: Create AuthContext with using authContext fields
from caller function.

main.go

@@ -554,7 +554,7 @@ func runRPC(wg *sync.WaitGroup, ctx context.Context) {
 	var opts []_grpc.ServerOption
 	if !dev {
 		_log.Infow("adding auth interceptor")
-		ac := authv3.NewAuthContext()
+		ac := authv3.NewAuthContext(kc, ks, as)
 		o := authv3.Option{}
 		opts = append(opts, _grpc.UnaryInterceptor(
 			ac.NewAuthUnaryInterceptor(o),

pkg/auth/v3/auth.go

@@ -37,8 +37,10 @@ type authContext struct {
 	as service.AuthzService
 }
 
-// NewAuthContext setup authentication and authorization dependencies.
-func NewAuthContext() authContext {
+// SetupAuthContext sets up new authContext along with its
+// dependencies. If the caller already has instances of authContext
+// fields created then use NewAuthContext instead.
+func SetupAuthContext() authContext {
 	var (
 		kc           *kclient.APIClient
 		kratosScheme string
@@ -93,3 +95,19 @@ func getEnvWithDefault(env, def string) string {
 	}
 	return val
 }
+
+// NewAuthContext instantiate authContext. NewAuthContext creates
+// authContext reusing dependency instances from calling function
+// instead of creating new instances. To create authContext along with
+// its dependencies, use SetupAuthContext.
+func NewAuthContext(
+	kc *kclient.APIClient,
+	apiKeySvc service.ApiKeyService,
+	authzSvc service.AuthzService,
+) authContext {
+	return authContext{
+		kc: kc,
+		ks: apiKeySvc,
+		as: authzSvc,
+	}
+}

pkg/auth/v3/middleware.go

@@ -20,7 +20,7 @@ type authMiddleware struct {
 
 func NewAuthMiddleware(opt Option) negroni.Handler {
 	return &authMiddleware{
-		ac:  NewAuthContext(),
+		ac:  SetupAuthContext(),
 		opt: opt,
 	}
 }