_sub_tag() could not find tag

I have a simple program using a file as sink:

from loguru import logger
import os

logger.remove()  # Remove the default logger

logfile = r'logfile.log'
loglevel = os.getenv('LOGLEVEL', 'INFO')
loglevel = loglevel.replace('"', '')

fmt='{time:YYYY:MM:DD HH:MM:SS} | {level: <8} | {name}:{function}:{line} - {message}'

logger.add(
    logfile,
    format=fmt,
    level=loglevel
)
logger.trace   ("TRACE    priority message")
logger.debug   ("DEBUG    priority message")
logger.info    ("INFO     priority message")
logger.success ("SUCCESS  priority message")
logger.warning ("WARNING  priority message")
logger.error   ("ERROR    priority message")
logger.critical("CRITICAL priority message")

It shows the following errors:

--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=14967), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'TRACE', 'line': 17, 'message': 'TRACE    priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 778917, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=17965), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'DEBUG', 'line': 18, 'message': 'DEBUG    priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 781915, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=28922), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'INFO', 'line': 19, 'message': 'INFO     priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 792872, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=33908), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'SUCCESS', 'line': 20, 'message': 'SUCCESS  priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 797858, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=40889), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'WARNING', 'line': 21, 'message': 'WARNING  priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 804839, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=45878), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'ERROR', 'line': 22, 'message': 'ERROR    priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 809828, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---
--- Logging error in Loguru Handler #1 ---
Record was: {'elapsed': datetime.timedelta(microseconds=53855), 'exception': None, 'extra': {}, 'file': 'script.py', 'function': '<module>', 'level': 'CRITICAL', 'line': 23, 'message': 'CRITICAL priority message', 'module': 'script', 'name': '__main__', 'process': '6208', 'thread': '10716', 'time': datetime(2019, 11, 24, 1, 32, 19, 817805, tzinfo=datetime.timezone(datetime.timedelta(seconds=28800), 'Malay Peninsula Standard Time'))}
Traceback (most recent call last):
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 89, in emit
    precomputed_format = self._decolorize_format(dynamic_format)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_handler.py", line 209, in _decolorize_format
    return AnsiMarkup(custom_markups=markups, strip=True).feed(format_, strict=True)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 174, in feed
    text = self._regex_tag.sub(self._sub_tag, text)
  File "C:\home\Anaconda3\lib\site-packages\loguru\_ansimarkup.py", line 248, in _sub_tag
    "make sure you did not misspelled it" % markup
ValueError: Tag "<module>" does not corespond to any known ansi directive, make sure you did not misspelled it
--- End of logging error ---

However, if I remove the format=fmt line, the code works perfectly.

[Delgan]

Sorry, I do not get your point. However, today is a new day and I have restarted my Windows 10. The problem disappeared when I removed or commented colorize=False.

I think there was some confusion when you tried to debug this problem, this code snippet actually always worked fine. However, I think that at one time or another, you had something very slightly different that would generate the error, just a small typo:

logger.add(
    logfile,
    format=format,
    level=loglevel
)

Note the format=format. The logger accepts a function to be passed to the format argument. In such case, Loguru will first call this function so that it dynamically generates the logs format instead of using a static str (like your fmt variable). This dynamically generated format is then used to create the log message, just as the static one would have been.

Here, the format function passed to the format argument is actually the built-in format(). For this reason, Loguru will internally do something like fmt = format(record), which results in:

"{'elapsed': datetime.timedelta(microseconds=10002), 'exception': None, 'extra': {}, 'file': (name='a.py', path='a.py'), 'function': '<module>', 'level': (name='INFO', no=20, icon='ℹ️'), 'line': 20, 'message': 'INFO     priority message', 'module': 'a', 'name': '__main__', 'process': (id=100026, name='MainProcess'), 'thread': (id=140006286919296, name='MainThread'), 'time': datetime(2019, 11, 24, 9, 8, 26, 483395, tzinfo=datetime.timezone(datetime.timedelta(seconds=3600), 'CET'))}"

Later, this will raise an error, because fmt is expected to look like "{time} - {message}" so that Loguru can call message = fmt.format_map(record).

That’s why I propose to add a check inside Loguru, to ensure that the format argument is different from the format() built-in. This is a mistake that can easily happen.

However, I still need to have loglevel.replace(...) if i set LOGLEVEL="TRACE" from a command prompt and run the script.

Yes, as you taught me, the set command should be used without quotes. I prefer not to automatically strip() the ", I don’t think Loguru should try to fix incorrect usage of OS commands.

[Delgan]

Check for builtins format() and filter() incorrectly passed as arguments has been added to  0.4.0. The new error message is more explicit.