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Depending on the shape Google App Engine is in, my app can take too long to start up:

Caused by: com.google.apphosting.api.DeadlineExceededException: This request (d872b776bcbbfd27) started at 2012/12/04 17:35:28.861 UTC and was still executing at 2012/12/04 17:36:28.348 UTC

The app contains a frontend and various backends and the whole app seems to get started once per instance, and many filters, security, etc. would not be used on the backends anyway.

Is is possible to split the app and deploy frontend and backend separately? And how would I run this maven based app on my dev server?

There's only vague doc - the closest I could find in the Google App Engine doc:
https://developers.google.com/appengine/docs/java/backends/overview
You can place your backends in a separate application root directory if you want to avoid sharing code or handlers, ...

And regarding the dev environment, net.kindleit.maven-gae-plugin is completely quiet about it's config params backend and/or backendDir.

Can someone provide more details on whether/how this can be reached?

Thanks, Stefan

Paul Collingwood
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Stefan Haebler
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  • What makes you think "splitting the frontend and backend" will make your app start up any faster? – Nick Johnson Dec 05 '12 at 11:15
  • To me, the Google doc sounds as if one could deploy two wars, one for the frontend and one for the backend and in case a frontend request comes in, not all backend servlets need to be started and vice versa. – Stefan Haebler Dec 07 '12 at 07:57
  • You can do that just fine by being selective about what code you call in your app - you don't need separate apps or versions, Java will only load the classes you ask it to. – Nick Johnson Dec 07 '12 at 10:43
  • Hmmm... I agree. Do you have any concrete pointers regarding the splitting? (My spring security app normally gets up in 20 seconds on an F2 frontend, so I seem to have enough reserve there.) – Stefan Haebler Dec 07 '12 at 14:59
  • I'm afraid I'm not familiar enough with App Engine Java to say for sure. Using a profiler would be a good first step. – Nick Johnson Dec 07 '12 at 16:47

1 Answers1

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You can upload multiple versions of your app. Each version can be completely independent of another version, though all version share the same datastore. For example, you can't typically mix Java/Python/Go within one runtime. However, you can have one version in Python and another version in Java.

Your default version is accessed at .appspot.com. Your other versions are accessed at ..appspot.com

What you'd need to do is:

1. clone your current app
2. change the version for your lean version
3. deploy lean version
4. modify the main version to access backends at <instance>.<backend-name>.<lean-version>.<appid>.appspot.com
5. deploy main version

Managing shared source may be another issue though, you may want to use soft links.

dragonx
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