Google App Engine Task Queue Gets 404 When Calling Google Cloud Endpoints API

Question

The following code works fine in the dev environment. The GET for "/ _ah / api / worker / v1 / tasks" calls the refresh () method, which adds the task to the default job queue in which POSTs processes "/ _ah / api / worker / v1 / tasks", which is processed by handle ( )

@Api(name = "worker", version = "v1", scopes = { Constants.EMAIL_SCOPE }, clientIds = { Constants.API_EXPLORER_CLIENT_ID, Constants.WEB_CLIENT_ID }) public class WorkerApi { @ApiMethod( name="refresh", path = "tasks", httpMethod = HttpMethod.GET) public void refresh() { MyObject myObject = new MyObject() Queue queue = QueueFactory.getDefaultQueue(); TaskOptions o = TaskOptions.Builder.withUrl("/_ah/api/worker/v1/tasks"); o.payload(ApiHelper.ObjectToJson(myObject )); queue.add(o); } @ApiMethod( name="handle", path = "tasks", httpMethod = HttpMethod.POST) public void handle(HttpServletRequest req, MyObject myObject) { // This handler is called if running in dev in environment // If running on GAE this handler is never called. } } 

Unfortunately, when deployed to a real Google App Engine application, the handle method is never called into the task queue.

Interestingly, I can successfully call the handler manually using the API API, which creates the following log in the GAE console:

 2014-11-24 12:01:30.914 /_ah/spi/my.test.application.WorkerApi.handle 200 1394ms 0kb Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36 module=default version=1 198.66.21.14 - - [24/Nov/2014:12:01:30 -0800] "POST /_ah/spi/my.test.application.WorkerApi.handle HTTP/1.1" 200 116 - "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36" "my-test-application.appspot.com" ms=1394 cpu_ms=1003 cpm_usd=0.000013 app_engine_release=1.9.16 instance=00c61b117c39338c333cff447edea78fa0f90d 

But when you call the task queue, 404 always returns, creating the following log in the GAE console:

 2014-11-24 12:07:54.727 /_ah/api/worker/v1/tasks 404 147ms 0kb AppEngine-Google; (+http://code.google.com/appengine) module=default version=1 0.1.0.2 - - [24/Nov/2014:12:07:54 -0800] "POST /_ah/api/worker/v1/tasks HTTP/1.1" 404 234 "https://my-test-application.appspot.com/_ah/spi/my.test.application.WorkerApi.refresh" "AppEngine-Google; (+http://code.google.com/appengine)" "my-test-application.appspot.com" ms=148 cpu_ms=23 cpm_usd=0.000026 queue_name=default task_name=9271899958322278984 pending_ms=61 app_engine_release=1.9.16 instance=00c61b117c7544e23aeb8d8b0c996da6d286d539 

Again, everything works as expected in the dev environment. Deployment failed in GAE. What am I doing wrong?

Comparing the log entries, I thought I found the problem and changed the code to:

 TaskOptions o = TaskOptions.Builder.withUrl("/_ah/spi/my.test.application.WorkerApi.handle"); 

Nope. This does not work. Now it is broken in dev environment and in GAE deployment.

Log from dev environment:

 [INFO] INFO: Web hook at http://127.0.0.1:8080/_ah/spi/my.test.application.WorkerApi.handle returned status code 404. Rescheduling.. 

Login from GAE console:

 2014-11-24 12:24:10.872 /_ah/spi/my.test.application.WorkerApi.handle 404 396ms 0kb AppEngine-Google; (+http://code.google.com/appengine) module=default version=1 0.1.0.2 - - [24/Nov/2014:12:24:10 -0800] "POST /_ah/spi/my.test.application.WorkerApi.handle HTTP/1.1" 404 96 "https://my-test-application.appspot.com/_ah/spi/my.test.application.WorkerApi.refresh" "AppEngine-Google; (+http://code.google.com/appengine)" "my-test-application.appspot.com" ms=397 cpu_ms=23 cpm_usd=0.000011 queue_name=default task_name=7132899958322278984 app_engine_release=1.9.16 instance=00c61b117c565c0a8aa81e1b86e50d78f0346330 

By the way, I am using the GAE SDK 1.9.16.

Answer 1

I have the same problem. On a local PC, this works well.

Perhaps the GAE server could not find a URL (endpoint) that is not explicitly written in web.xml.

To fix this problem, create another servlet for the worker.

For example, the endpoint method

  Queue queue = QueueFactory.getDefaultQueue(); TaskOptions o = TaskOptions.Builder.withUrl("/work"); o.param( "target" , target) ; // target is String in this case queue.add(o); 

war / WEB-INF / web.xml

 <web-app ...> ... default servet (SystemServiceServlet) ... <servlet> <servlet-name>WorkerServlet</servlet-name> <servlet-class>com.example.your.package.WorkerServlet</servlet-class> </servlet> .... default mapping file ... <servlet-mapping> <servlet-name>WorkerServlet</servlet-name> <url-pattern>/work</url-pattern> </servlet-mapping> 

and create the file WorkerServlet.java as

 public class WorkerServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String target = req.getParameter("target"); // do something resp.setStatus( resp.SC_OK ); } } 

In this case, url / work can be found by the GAE server, and Queue works well.

Answer 2

Just add KNaito answer

  RequestDispatcher dispatcher = req.getRequestDispatcher(target); dispatcher.forward(req, resp); 

To finally redirect the request to the right place with both parameters.