Does python-fire have some method to do unified exception handling?

[hujianxin]

No description provided.

[kinow]

Came here looking for the same (as I knew click had it). Couldn't find anything in docs/examples, so I guess it leaves that part to the user?

[dbieber]

That's correct.

If there's an error caused by the user's usage (e.g. they try to access a command that doesn't exist, or don't provide required arguments for a command), then internally Fire raises a FireError with details about that error. Fire catches its own errors though, and will raise a FireExit (a subclass of SystemExit that contains information about the error) with status code 2, indicating a user error.

If there's a Python error in the CLI, then Fire doesn't catch it; it simply surfaces to the user as a Python error. You can certainly catch errors raised by CLI (both ordinary Python errors as well as FireExits) if you want custom error handling code.

[dbieber]

Here's the real answer to your question:

Yes, Fire catches fire.core.FireErrors and displays them succinctly alongside the usage information for the component at the time of the error.

So e.g. you can do something like

import fire, math
def sqrt(x):
  if x < 0:
    raise fire.core.FireError('x must be >= 0')
  return math.sqrt(x)
fire.Fire(sqrt)

Then when you use it you'll see:

> cli -2
ERROR: x must be >= 0
Usage: mathex.py X

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

Sorry it's not in the docs yet!

[dbieber]

Answered in previous comment; closing!