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 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!

Do you want py3 support or other nice improvements ? Join us to make log rocking better!

• Lev Orekhov @lorehov
• Étienne BERSAC @bersace