trust_env=True of aiohttp.ClientSession should not print a warning log nor try to access each time a file

[siom79]

Long story short

When setting trust_env=True for aiohttp.ClientSession, a warning like the following one is printed to the log if the file .netrc is missing.

2018-09-26 08:10:07 WARNING (MainThread) [aiohttp.client] could't find .netrc file

This should not happen as the intention is to only access environment variables. Beyond that, the file access should only happen once and not again and again for each instance of aiohttp.ClientSession. This is for example the reason why pull request 16874 for home-assistant was rejected.

Expected behaviour

Setting trust_env=True for aiohttp.ClientSession should not print a warning and should not try to access a file each time.

Actual behaviour

If the file .netrc is missing, a warning is printed and for each instance of aiohttp.ClientSession the file check is repeated.

Steps to reproduce

Create an instance of aiohttp.ClientSession with trust_env=True when there is no .netrc file.

Your environment

aiohttp version 3.4.4, used as client, running on Ubuntu 18.04 with python 3.6.6

[aio-libs-bot]

GitMate.io thinks the contributor most likely able to help you is @asvetlov.

Possibly related issues are #2867 (aiohttp.ClientSession reconnect ), #919 (Suggesting aiohttp.ClientSession.abort()), #2209 (ClientSession.close() is a coroutine warning), #3248 (history tuple on ClientResponseError empty with raise_for_status() or ClientSession(raise_for_status=True)), and #975 (aiohttp.ClientSession raises ServerDisconnectedError).

[asvetlov]

A warning is addressed by #3267

Regarding caching .netrc parsing results -- it could confuse people.
If we add caching it should be an opt-in configurable option I guess.

[cooperlees]

I see fixes for this are all landed - When do we expect a >= 3.4.4 release as I'd love to enable this for bandersnatch (as linked).

[asvetlov]

No release date is scheduled.
This month perhaps.

[asvetlov]

Logging is tuned, file access caching idea is rejected

[lock]

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