Add withAppEngineService() to package:appengine

lib/src/appengine_internal.dart

Index: lib/src/appengine_internal.dart
diff --git a/lib/src/appengine_internal.dart b/lib/src/appengine_internal.dart
index 3ed2cd7494bdff3f68f93c5c15367f93d936891e..0f217b69fdf9dac220897fff4c6f7c219a882c75 100644
--- a/lib/src/appengine_internal.dart
+++ b/lib/src/appengine_internal.dart
@@ -97,12 +97,17 @@ Future<ContextRegistry> initializeAppEngine() {
     }
   }
 
-  var context = getDockerContext();
-  var rpcService = initializeRPC();
-
-  return getStorage(context).then((storage) {
-    return new ContextRegistry(rpcService, storage, context);
-  });
+  if (_contextRegistry != null) {
+    return new Future.value(_contextRegistry);
+  } else {
+    var context = getDockerContext();
+    var rpcService = initializeRPC();
+
+    return getStorage(context).then((storage) {
+      _contextRegistry = new ContextRegistry(rpcService, storage, context);
+      return _contextRegistry;
+    });
+  }
 }
 
 void initializeContext(Services services) {
@@ -127,14 +132,20 @@ void initializeRequestSpecificServices(Services services) {
   users.registerUserService(services.users);
 }
 
-Future runAppEngine(void handler(request, context), void onError(e, s)) {
+Future withAppEngineServices(Future callback()) {
   return initializeAppEngine().then((ContextRegistry contextRegistry) {
-    _contextRegistry = contextRegistry;
-    var appengineServer = new AppEngineHttpServer(_contextRegistry);
-    var backgroundServices = _contextRegistry.newBackgroundServices();
-
-    ss.fork(() {
+    return ss.fork(() {
+      var backgroundServices = _contextRegistry.newBackgroundServices();
       initializeContext(backgroundServices);
+      return callback();
+    });
+  });
+}
+
+Future runAppEngine(void handler(request, context), void onError(e, s)) {
+  return initializeAppEngine().then((ContextRegistry contextRegistry) {

[wibling, 2014/12/03 11:11:03]

Why call initializeAppEngine here? 

Isn't it enough to call withAppEngineServices() which then sets up the
_contextRegistry by calling initializeAppEngine?

[kustermann, 2014/12/03 11:14:42]

Sure. Forgot to remove that wrapper.

Done

+    return withAppEngineServices(() {
+      var appengineServer = new AppEngineHttpServer(_contextRegistry);
       appengineServer.run((request, context) {
         ss.fork(() {
           initializeRequestSpecificServices(context.services);
@@ -170,7 +181,5 @@ Future runAppEngine(void handler(request, context), void onError(e, s)) {
       });
       return appengineServer.done;
     });
-
-    return new Future.value();
   });
 }