带有GWT的App Engine模块

Question

I'm looking for advice on how to set up a Google App Engine project that involves multiple modules where one module a GWT project. I've read through Google App Engine module documentation ( https://developers.google.com/appengine/docs/java/modules/ ) and found some help on Stackoverflow such as this post GWT GAE app engine modules using appengine-skeleton-archetype . However, it this involves a lot of pieces so I'd love to get some advice.

Platform considerations:

• Eclipse
• Google Plugin for Eclipse ( https://developers.google.com/eclipse/ )
• Web Tools Platform ( https://developers.google.com/appengine/docs/java/webtoolsplatform )
• Mac
• Java
• Google App Engine Modules ( https://developers.google.com/appengine/docs/java/modules/ )
• Maven: I'll use it if I have to; I've gone through tutorials for the command-line version but not the Eclipse plugin.

Design:

Conceptually, I'd like a system that does computationally intensive work that can be scheduled by an end user with nice HTML interface. I really like GWT and the Google Plugin for Eclipse. I just can't figure out how to make it work with modules which allow for indefinite deadlines (as described at https://developers.google.com/appengine/docs/java/modules/#Java_Instance_scaling_and_class )

Architecture:

1] GWT user interface: I'd like to use the Google Plugin for Eclipse to generate a basic GWT project because I'm very familiar with Google Plugin for Eclipse.

1.a] I assume it needs to be its own Eclipse project and then added to added to an EAR as described here https://developers.google.com/appengine/docs/java/webtoolsplatform#enterprise_application .

1.b] I assume it needs to be configured with instance scaling Automatic as described here https://developers.google.com/appengine/docs/java/modules/#Java_Instance_scaling_and_class . Do I have to specify Automatic or does it assume Automatic for a GWT module created with the Google Plugin for Eclipse?

2] Basic Scaling Module: I'd like a module that's capable of running for a long time. In the past I used scheduled tasks and let my jobs run in 10 min intervals (the maximum allowed processing time for scheduled tasks). But according to https://developers.google.com/appengine/docs/java/modules/#Java_Instance_scaling_and_class I can have a module with Scaling Type = Basic and that will allow for unlimited processing time. Me likey.

3] Task Queues: I plan to use Task Queues ( https://developers.google.com/appengine/docs/java/taskqueue/ ) to get the GWT user interface module to tell the Basic Scaling Module to begin its work. I've never used Task Queues, so I'd appreciate validation that this should work.

To summarize my questions:

A] Is my design concept feasible?

B] Is the architecture I've outline possible?

C] How do I actually produce the desired architecture? Should I manually create all the config files described at https://developers.google.com/appengine/docs/java/modules/#Java_Application_hierarchy ? Or is it supposed to be generated by Maven, Web Tools Platform, or Google Plugin for Eclipse?

D] More specifically, I'm able to set up a basic EAR and WAR as per https://developers.google.com/appengine/docs/java/webtoolsplatform#creating_a_project . And I'm able to create a GWT project using the Google Plugin for Eclipse. But how do I add that GWT project to the EAR? Am I supposed to configure the files myself or is it supposed to be done for me by Maven, Web Tools Platform, or Google Plugin for Eclipse?

The more detailed answer you can provide, the better, because I don't have comprehensive knowledge of all these technologies. I'm a guy who glues cool new things together to prototype stuff, so I rarely get the time to learn a technology in-depth. My strongest knowledge is Google Plugin for Eclipse so ideally I'd like to leverage that as much as possible and do as little as possible with Maven and the Web Tools Platform.

Thank you so much Stackoverflowers! :-P

Michael

Answer 1

I've received the following answer from Albert at Google Cloud Platform Support:

After intensive research and reviewing this with my team, it seems like having this working through Eclipse isn't as easy as we'd want it. Albeit possible to set up a module as a GWT application, it will not be recognized as GWT and the compilation will therefore not be available via the right-click context menu. This is due to the Eclipse Plugin not recognizing modules, and the Enterprise Application Project type of project not allowing to set a module as a GWT application.

I would recommend that you open a feature request using the public issue tracker[1] for that functionality to be added in the future. In the meantime, the easiest workaround would be to do exactly what we have tried, which is to code the application in a GWT app, and then copy/paste the files into the appropriate directories after compilation. Another alternative would be to run the command line tool[2] on the GWT directory to compile the project.

I know that these aren't perfect solutions, but they may be helpful to you.

As this should answer your question, I'll go ahead and set the case to close in a few days. I'd also like to take the opportunity to thank you for all your patience through this matter. It's been a pleasure working with you.

Sincerely,

Albert Cloud Platform Support

[1] Google Plugin for Eclipse Issue Tracker: https://code.google.com/p/google-plugin-for-eclipse/ [2] GWT Compilation: http://www.gwtproject.org/doc/latest/RefCommandLineTools.html