diff options
Diffstat (limited to 'Doc/howto')
| -rw-r--r-- | Doc/howto/functional.rst | 2 | ||||
| -rw-r--r-- | Doc/howto/isolating-extensions.rst | 3 | ||||
| -rw-r--r-- | Doc/howto/logging-cookbook.rst | 62 |
3 files changed, 64 insertions, 3 deletions
diff --git a/Doc/howto/functional.rst b/Doc/howto/functional.rst index 78e56e0c64f..053558e3890 100644 --- a/Doc/howto/functional.rst +++ b/Doc/howto/functional.rst @@ -1217,7 +1217,7 @@ flow inside a program. The book uses Scheme for its examples, but many of the design approaches described in these chapters are applicable to functional-style Python code. -https://www.defmacro.org/ramblings/fp.html: A general introduction to functional +https://defmacro.org/2006/06/19/fp.html: A general introduction to functional programming that uses Java examples and has a lengthy historical introduction. https://en.wikipedia.org/wiki/Functional_programming: General Wikipedia entry diff --git a/Doc/howto/isolating-extensions.rst b/Doc/howto/isolating-extensions.rst index fbc426ba1d7..7da6dc8a397 100644 --- a/Doc/howto/isolating-extensions.rst +++ b/Doc/howto/isolating-extensions.rst @@ -626,8 +626,7 @@ Open Issues Several issues around per-module state and heap types are still open. -Discussions about improving the situation are best held on the `capi-sig -mailing list <https://mail.python.org/mailman3/lists/capi-sig.python.org/>`__. +Discussions about improving the situation are best held on the `discuss forum under c-api tag <https://discuss.python.org/c/core-dev/c-api/30>`__. Per-Class Scope diff --git a/Doc/howto/logging-cookbook.rst b/Doc/howto/logging-cookbook.rst index 7d64a02358a..ae2697fbce3 100644 --- a/Doc/howto/logging-cookbook.rst +++ b/Doc/howto/logging-cookbook.rst @@ -4078,6 +4078,68 @@ lines. With this approach, you get better output: WARNING:demo: 1/0 WARNING:demo:ZeroDivisionError: division by zero +How to uniformly handle newlines in logging output +-------------------------------------------------- + +Usually, messages that are logged (say to console or file) consist of a single +line of text. However, sometimes there is a need to handle messages with +multiple lines - whether because a logging format string contains newlines, or +logged data contains newlines. If you want to handle such messages uniformly, so +that each line in the logged message appears uniformly formatted as if it was +logged separately, you can do this using a handler mixin, as in the following +snippet: + +.. code-block:: python + + # Assume this is in a module mymixins.py + import copy + + class MultilineMixin: + def emit(self, record): + s = record.getMessage() + if '\n' not in s: + super().emit(record) + else: + lines = s.splitlines() + rec = copy.copy(record) + rec.args = None + for line in lines: + rec.msg = line + super().emit(rec) + +You can use the mixin as in the following script: + +.. code-block:: python + + import logging + + from mymixins import MultilineMixin + + logger = logging.getLogger(__name__) + + class StreamHandler(MultilineMixin, logging.StreamHandler): + pass + + if __name__ == '__main__': + logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)-9s %(message)s', + handlers = [StreamHandler()]) + logger.debug('Single line') + logger.debug('Multiple lines:\nfool me once ...') + logger.debug('Another single line') + logger.debug('Multiple lines:\n%s', 'fool me ...\ncan\'t get fooled again') + +The script, when run, prints something like: + +.. code-block:: text + + 2025-07-02 13:54:47,234 DEBUG Single line + 2025-07-02 13:54:47,234 DEBUG Multiple lines: + 2025-07-02 13:54:47,234 DEBUG fool me once ... + 2025-07-02 13:54:47,234 DEBUG Another single line + 2025-07-02 13:54:47,234 DEBUG Multiple lines: + 2025-07-02 13:54:47,234 DEBUG fool me ... + 2025-07-02 13:54:47,234 DEBUG can't get fooled again + .. patterns-to-avoid: |