How do I get a stack trace from Zappa with Python on AWS Lambda

Question

I'm using the Zappa framework https://github.com/Miserlou/Zappa with Python and Flask on AWS Lambda. When it raises an exception it appears in the CloudWatch log but is illegible to me. I do get a normal Flask stack trace returned from a HTTP GET in debug builds however.

My question is how do I get a reasonable (Flask) stack trace in logs / from production code? When exceptions are raised in production all I have is log messages.

Nice stack trace from HTTP GET:

Traceback (most recent call last):
  File "/var/task/handler.py", line 96, in handler
    response = Response.from_app(app, environ)
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/Werkzeug/werkzeug/wrappers.py", line 865, in from_app
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/Werkzeug/werkzeug/wrappers.py", line 57, in _run_wsgi_app
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/Werkzeug/werkzeug/test.py", line 871, in run_wsgi_app
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/zappa/zappa/middleware.py", line 78, in __call__
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1836, in __call__
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1820, in wsgi_app
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 271, in error_router
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1403, in handle_exception
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 268, in error_router
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1817, in wsgi_app
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1477, in full_dispatch_request
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 271, in error_router
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1381, in handle_user_exception
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 268, in error_router
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1475, in full_dispatch_request
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/app.py", line 1461, in dispatch_request
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 477, in wrapper
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-v6XvIH/flask/flask/views.py", line 84, in view
  File "/private/var/folders/1j/5zcxjzkx29b8tfgrh2y90wt80000gn/T/pip-build-jvEYWI/flask-restful/flask_restful/__init__.py", line 587, in dispatch_request
  File "/Users/notacat/src/aws-lambda/zappa/controllers/error_controller.py", line 15, in get
TestError: 'This is a test error'

Hard to understand stack trace from CloudWatch log:

...Rlc3RFcnJvcjogJ1RoaXMgaXMgYSB0ZXN0IGVycm9yJzxiciAvPjwvcHJlPg==: 
Exception Traceback (most recent call last): 
File "/var/task/handler.py", line 161, in lambda_handler return LambdaHandler.lambda_handler(event, context) 
File "/var/task/handler.py", line 55, in lambda_handler return cls().handler(event, context) 
File "/var/task/handler.py", line 155, in handler raise Exception(exception) 
Exception: PCFET0NUWVBFIGh0bWw+NTAwLiBGcm9tIFphcHBhOiA8cHJlPidUaGlzIGl...

Answer 1

This looks like an old question, but I'm using Zappa 0.45.1 and I can see my python stack trace when an error occurs through both the CloudWatch AWS terminal and by using zappa tail which provides the CloudWatch logs and some added information.