如何在现有Java应用程序中添加Python模块

Question

I have a GAE Java app already deployed which is using Datastore. Now, I need to split that app in modules and have second module which is written in Python to access that same Datastore. I cannot find useful info on how to split app in modules in a way that:

• it supports Java in first module and Python in second module
• both modules can access same Datastore (I guess this implies since both are part of same GAE application)

Main question would be: what are steps to do define these two modules with different programming languages.

Thanks in advance.

Answer 1

You can use app.yaml to configure your main (Java) module, as detailed at https://cloud.google.com/appengine/docs/java/configyaml/appconfig_yaml , and separate .yaml files to configure your other (Python, PHP, and/or Go -- or also, some of them could also be Java!-)) modules, as detailed at https://cloud.google.com/appengine/docs/python/modules/#Python_Configuration .

As you suspect, all modules always do access exactly the same instance of the datastore.

So for example you could have in app.yaml ...:

application: myapp
version: alpha-001
runtime: java
api_version: 1

handlers:
- url: /myjava/*
  servlet: myapp.myservlets.DoItAllServlet

to map all urls /myjava/something to that single servlet, and in eg mypython.yaml

application: myapp
module: mypython
version: v1
runtime: python27

handlers:
- url: /mypy/*
  script: mypython.app

to map all URLs /mypy/something to the single WSGI application bound to global variable app in module mypython.py . Of course, there are huge numbers of degrees of freedom on both the main ("default") module, and the other ones, I'm just trying to show the very simplest "skeleton" here!-)