Better error handling #509

[whysage]

Add providers log on error.

[whysage]

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

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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')

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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 :-)

[whysage]

Hi
@rmk135 @gen-xu
Any updates?

[whysage]

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