How can i access the exception that fire handles?

[securisec]

I know that whether I am using a class or a function, fire will internally handle the exception and show the help if there is an issue.

So considering fire_obj = fire.Fire(SomeClass), how can I access that exception from fire_obj? I know that fire_obj points to a new instance of SomeClass, but I am trying to capture and handle the exceptions that fire is handling internally when it shows the help or exceptions.

When I wrap it in a try except, I can see that the exception is FireExit, but I dont want the python-fire help message to print (which is printing from the code in the library). I want to instead raise my own exception, but even better, access the exception that happened inside SomeClass which is trigger the error.

@dbieber

[securisec]

bump

[sanmao2018]

rewrite fire code？use monkey patch？

[dbieber]

try:
  fire.Fire(SomeClass)
except fire.core.FireError as e:
  pass  # Access it here.

You can also catch fire.core.FireExit exceptions.
I will try to provide a more complete answer explaining how to use these in the future, but this should get you started.

[securisec]

Thanks @dbieber ! Yes, a complete example would be awesome! I already figured out most of it in a try catch, but what I am really trying to suppress is the FireExit exception. Because it blurts out a lot of data because its instantiating a class with many methods. I am trying to override the FireExit message with my own,.

[securisec]

This is where i am tyring to handle it. @dbieber code

[securisec]

@dbieber bump. Still cant figure out how to handle https://github.com/google/python-fire/blob/master/fire/core.py#L275 without forking and patching...

[dbieber]

1. If you want to insert your own error handling into Fire, just have your code raise a FireError.

import fire

class SomeClass:

    def demo(self, x):
        if x > 5:
          raise fire.core.FireError('x is too large')

fire.Fire(SomeClass)

$ python example.py demo 10
ERROR: x is too large
Usage: example.py demo X

For detailed information on this command, run:
  example.py demo --help

2. Looks like we don't have a way to suppress the output right now. I'll consider this a feature request.

Here's an example of accessing the error / trace though:

import fire

class SomeClass:

    def a(self, x):
        return x

try:
  fire.Fire(SomeClass)
except fire.core.FireExit as e:
  print(e.trace)  # e.trace is a FireTrace object

FireTrace source:

python-fire/fire/trace.py

Line 45 in b77f5ae

class FireTrace(object):

[securisec]

Thanks @dbieber . Yes, I had figured out this part, and am handing the error in fire.core.FireExit so stop it closing out. Now trying to figure out how to access the traceback and send back my own exception handler.