Logger redirect¶

In unittest class, redirect stdout/stderr. Essential for synchronous logging

class logging_strict.tech_niques.logger_redirect.LoggerRedirector¶

unittest redirects sys.stdout and sys.stderr. Keep a reference to the real streams so we can later be reverted. Logging goes to the wrong IO streams. Upon failure, there are no log messages.

Redirect to the correct IO streams.

Required for the unittest discover command: --buffer option

_real_stdout: Hold sys.stdout reference. Restores sys.stdout at the end of the context manager

_real_stderr: Hold sys.stderr reference. Restores sys.stdout at the end of the context manager

Usage

In a unittest module (level), setup logging.basicConfig

>>> import sys
>>> import logging
>>> logging.basicConfig(
...     format='%(module)s %(levelname)s: %(message)s',
...     level=logging.INFO,
...     stream=sys.stdout,
... )

In a unittest module class

import sys
import logging
from logging_strict.tech_niques import LoggerRedirector
def setUp(self):
    # unittest has reassigned sys.stdout and sys.stderr by this point

    g_module = f"[app_name].tests.test_[module name]"
    self._LOGGER = logging.getLogger(g_module)

    # %(asctime)s
    logging.basicConfig(
         format="%(levelname)s %(module)s: %(message)s",
         level=logging.INFO,
         stream=sys.stdout,
    )
    LoggerRedirector.redirect_loggers(
        fake_stdout=sys.stdout,
        fake_stderr=sys.stderr,
    )
def tearDown(self):
    # unittest will revert sys.stdout and sys.stderr after this
    LoggerRedirector.reset_loggers(
        fake_stdout=sys.stdout,
        fake_stderr=sys.stderr,
    )

Logger redirect¶

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