bad logging documentation {}-formatting placeholder

[AlberLC]

Documentation

%-formatting (It works)

import logging
logging.basicConfig(filename='example.log', format='%(msecs)03d - %(message)s')
logging.warning('foo')

example.log:

273 - foo

✅

Now using the the modern {} format syntax, as the documentation says (doesn't work)

import logging
logging.basicConfig(filename='example.log', format='{msecs:03d} - {message}', style='{')
logging.warning('foo')

❌

Exception:

--- Logging error ---
Traceback (most recent call last):
 File "...\Python\Python310\lib\logging\__init__.py", line 1100, in emit
 msg = self.format(record)
 File "...\Python\Python310\lib\logging\__init__.py", line 943, in format
 return fmt.format(record)
 File "...\Python\Python310\lib\logging\__init__.py", line 681, in format
 s = self.formatMessage(record)
 File "...\Python\Python310\lib\logging\__init__.py", line 650, in formatMessage
 return self._style.format(record)
 File "...\Python\Python310\lib\logging\__init__.py", line 440, in format
 return self._format(record)
 File "...\Python\Python310\lib\logging\__init__.py", line 458, in _format
 return self._fmt.format(**values)
ValueError: Unknown format code 'd' for object of type 'float'
Call stack:
 File "...\main.py", line 26, in <module>
 logging.warning('foo')
Message: 'foo'
Arguments: ()

Proposed fix

Use {msecs:03.0f} placeholder.

import logging
logging.basicConfig(filename='example.log', format='{msecs:03.0f} - {message}', style='{')
logging.warning('foo')

example.log:

273 - foo

✅

Linked PRs

• gh-109451:bad logging documentation {}-formatting placeholder #109460
• gh-109451: Fix logging documentation #109465
• [3.11] gh-109451: Fix wrong format specifier in logging documentation (GH-109465) #109482
• [3.12] gh-109451: Fix wrong format specifier in logging documentation (GH-109465) #109483

[sobolevn]

Please, send a PR :)