Fix default access_log_format to correct value

[azhpushkin]

What do these changes do?

Fixing wrong default value of access log format

Are there changes in behavior for the user?

Should not affect anything

Related issue number

#2649

Checklist

• I think the code is well written
• Documentation reflects the changes
• Add a new news fragment into the CHANGES folder

[fafhrd91]

aiohttp uses None for specific reason. enabled server logging significantly reduce performance even if logging it self is not enabled.

[azhpushkin]

Problem of this PR is more about having bad parameters, I tried to describe everything in details in the issue.
Access logger is enabled while default argument of class is set (access_logger is not False). I could set it to None in this PR also, however this is another story so I would like to leave it the way it is .

[fafhrd91]

drop performance by 20% is not good change, especially for default parameters.

[codecov-io]

Codecov Report

Merging #2650 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2650   +/-   ##
=======================================
  Coverage   97.92%   97.92%           
=======================================
  Files          38       38           
  Lines        7267     7267           
  Branches     1262     1262           
=======================================
  Hits         7116     7116           
  Misses         47       47           
  Partials      104      104

Impacted Files	Coverage Δ
aiohttp/web.py	98.76% <ø> (ø)	⬆️

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[azhpushkin]

@fafhrd91 Sorry, maybe I`m not following something but with current default params for me views are not working at all. Access logger is being initialized for each request in the following part of code:

aiohttp/aiohttp/web_protocol.py

Lines 135 to 139 in 19c138c

	if access_log:
	self.access_logger = access_log_class(
	access_log, access_log_format)
	else:
	self.access_logger = None

As access logger over here is True access_log_class(...) is called. Afterwards, default AccessLogger.init is called, than compile_format() is called and it fails in the following line:

aiohttp/aiohttp/helpers.py

Line 352 in 19c138c

for atom in self.FORMAT_RE.findall(log_format):

This is happening because log_format over here is None.
Also there is no exception or traceback being produced before loop is closed. Can you please try Steps to reproduce to see whether you getting this problem too?

[fafhrd91]

you are right, sorry. somehow I thought that access log is disabled by default.

[asvetlov]

Access log was enabled by default in aiohttp 2.x
The issue is a result of my refactoring for AppRunner, I forgot to set proper default value.

[asvetlov]

Thanks

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a [new issue] for related bugs.
If you feel like there's important points made in this discussion, please include those exceprts into that [new issue].
[new issue]: https://github.com/aio-libs/aiohttp/issues/new