Better error handling #509

[whysage]

Add providers log on error.

[whysage]

@rmk135
Please review PR.
I'll not sure about it.

---

Here - #510 - you write that after reraise exception all exceptions will be just general 'Exception'.
I test my code by adding addition try here
src/dependency_injector/providers.pxd
line 582
try: return call(*args, **kwargs) except Exception as exception: raise exception

and receive type of Exception was TypeError (I used this demo
https://github.com/ets-labs/python-dependency-injector/blob/master/examples/demo/with_di.py
without env var timeout - so error was - TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType')

---

Also, I'm not sure about printing providers, Maybe we can log them somewhere.
Please advise.

Addition idea about problem was to add ENV var like DEPENDENCY_INJECTION_DEBUG_MODE
and print called providers only it is enabled.

I think this issue is very important - for me, it is real hell to find error in dozens providers by unclear error message.
Please help :-)

[rmk135]

I'm not quite sure about using print() here. It will send some data to stdout, which might not always be the desired behavior.

The idea, generally, looks interesting. Maybe we can use the logging module?

[gen-xu]

I would agree with @rmk135 to use the logging module with logger.exception with some extra useful messages as it allows users to have more control on the output through logging.config. Meanwhile, I believe the LogRecord may not provide precise info given the cython context (caller line number, stacktrace etc.)

[whysage]

Thank you for reply!

@rmk135 @gen-xu

Please look at updated pull request.
I hope logging.debug() is good idea because, by default, we have warning log level, and I hope no one use debug level in production) - so nothing will change for current users until logging level set to debug.
If this request will be accepted - I'll add article to documentation about this.

[whysage]

Hi
@rmk135 @gen-xu
Any updates?

[whysage]

Hi!
@rmk135 @gen-xu
ping for updates)