pylogctx 1.9

Python Logging Context

pylogctx is a library for enriching each logs records from a context. Typical usage is for adding some request_id to all logs in order to make troubleshooting more comfortable. This context is shared by all piece of code using logging, transparently.

import logging.config

from pylogctx import context as log_context


logging.config.dictConfig({
    'formatters': {'json': {
        '()': 'pythonjsonlogger.jsonlogger.JsonFormatter',
        'format': "%(asctime)s %(name)s %(levelname)s %(message)s",
    }},
    'filters': {'context': {
        '()': 'pylogctx.AddContextFilter',
    }},
    'handlers': {'console': {
        'class': 'logging.StreamHandler',
        'filters': ['context'],
        'formatter': 'json',
    }},
    'root': {
        'level': 'INFO',
        'handlers': ['console'],
    },
})


logger = logging.getLogger(__name__)


def mycode(request, ticket_id):
    # push new fields
    log_context.update(requestId=uuid.uuid4())
    myticket = get_object_or_404(models.Ticket, pk=ticket_id)

    # push objects, they will be adapted to log fields
    log_context.update(myticket):

    # Log as usual
    logger.info("Working on %r", myticket)

    for comment in myticket.comments:
        # A context manager allow to push and pop fields
        with log_context(comment):
            logger.info("Working on comment %r", comment)
            # code, use external libs, etc.

    # Don't forget to clear the context for the next request. Use the
    # middleware to have it clean.
    log_context.clear()

The output looks like:

{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on <Ticket #1>', 'ticketId': 1, 'requestId': 'c5521138-031a-4da6-b9db-c9eda3e090f1'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on comment <Comment #4>', 'ticketId': 1, 'ticketCommentId': 4, 'requestId': 'c5521138-031a-4da6-b9db-c9eda3e090f1'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on comment <Comment #5>', 'ticketId': 1, 'ticketCommentId': 5, 'requestId': 'c5521138-031a-4da6-b9db-c9eda3e090f1'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on comment <Comment #78>', 'ticketId': 1, 'ticketCommentId': 78, 'requestId': 'c5521138-031a-4da6-b9db-c9eda3e090f1'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on comment <Comment #9>', 'ticketId': 1, 'ticketCommentId': 9, 'requestId': 'c5521138-031a-4da6-b9db-c9eda3e090f1'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on <Ticket #890>', 'ticketId': 890, 'requestId': 'c64aaae7-049b-4a02-929b-2d0ac9141f5c'}
{'loggerName': 'package.module', 'levelname': 'INFO', 'message': 'Working on comment <Comment #80>', 'ticketId': 890, 'ticketCommentId': 80, 'requestId': 'c64aaae7-049b-4a02-929b-2d0ac9141f5c'}

Install it with your favorite python package installer:

$ pip install pylogctx

There is a few helpers for Celery and Django projects. See USAGE for details!