Add a pre-deployment sanity check

[Miserlou]

Just display warnings if the app_module doesn't exist to avoid the

 UnboundLocalError: local variable 'app_module' referenced before assignment 

that happens from putting the wrong values in zappa_settings.

[tipu]

on it.

[tipu]

I'm going to put the addition for this in zappa/cli.py:create_package(). Does this seem like a suitable place?

[Miserlou]

This would probably be better to but in zappa.py so that it could be used by other clients. We should expect that this function may grow over time.

[tipu]

@Miserlou zappa/zappa.py appears to be unaware of the zappa_settings reference that zappa/cli holds onto. Should I inject the zappa_settings into zappa/zappa.py or should I implement it in the update method within ZappaCLI? The zappa_settings is necessary to access the app_function key of zappa_settings.json.

[collingreen]

It would be helpful to check types on config values -- for example, memory_size, parameter_depth, timout_seconds, etc all need to be numbers, not strings. If they are strings, zappa will zip your project, upload it, then fail with an error:

Parameter validation failed:
Invalid type for parameter MemorySize, value: 128, type: <type 'unicode'>, valid types: <type 'int'>, <type 'long'>

[Miserlou]

This recently happened to somebody in IRC:

[1471899440322] No module named your_module
[1471899440322] No module named your_module: ImportError
Traceback (most recent call last):
 File "/var/task/handler.py", line 345, in lambda_handler
   return LambdaHandler.lambda_handler(event, context)
 File "/var/task/handler.py", line 122, in lambda_handler
   return cls().handler(event, context)
 File "/var/task/handler.py", line 317, in handler
   raise e
ImportError: No module named your_module

Could we check if the specified module exists before uploading?