django-structlog 1.1.2

Structured Logging for Django

django-structlog

django-structlog is a structured logging integration for Django project using structlog

Logging will then produce additional cohesive metadata on each logs that makes it easier to track incident.

Logging comparison

Standard logging:

>>> import logging
>>> logger = logging.get_logger(__name__)
>>> logger.info("An error occurred")

An error occurred

Well… ok

With django-structlog and flag_line:

>>> import structlog
>>> logger = structlog.get_logger(__name__)
>>> logger.info("an_error_occurred", bar="Buz")

timestamp='2019-04-13T19:39:31.089925Z' level='info' event='an_error_occurred' logger='my_awesome_project.my_awesome_module' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0'

Then you can search with commands like:

$ cat logs/flat_line.log | grep request_id='3a8f801c-072b-4805-8f38-e1337f363ed4'

With django-structlog and json

>>> import structlog
>>> logger = structlog.get_logger(__name__)
>>> logger.info("an_error_occurred", bar="Buz")

{"request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "event": "an_error_occurred", "timestamp": "2019-04-13T19:39:31.089925Z", "logger": "my_awesome_project.my_awesome_module", "level": "info", "bar": "buz"}

Then you can search with commands like:

$ cat logs/json.log | jq '.[] | select(.request_id="3a8f801c-072b-4805-8f38-e1337f363ed4")' -s

Getting Started

These steps will show how to integrate the middleware to your awesome application.

Installation

Install the library

pip install django-structlog

Add middleware

MIDDLEWARE = [
    # ...
    'django_structlog.middlewares.RequestMiddleware',
]

Add appropriate structlog configuration to your settings.py

import structlog

LOGGING = {
    "version": 1,
    "disable_existing_loggers": False,
    "formatters": {
        "json_formatter": {
            "()": structlog.stdlib.ProcessorFormatter,
            "processor": structlog.processors.JSONRenderer(),
        },
        "plain_console": {
            "()": structlog.stdlib.ProcessorFormatter,
            "processor": structlog.dev.ConsoleRenderer(),
        },
        "key_value": {
            "()": structlog.stdlib.ProcessorFormatter,
            "processor": structlog.processors.KeyValueRenderer(key_order=['timestamp', 'level', 'event', 'logger']),
        },
    },
    "handlers": {
        "console": {
            "class": "logging.StreamHandler",
            "formatter": "plain_console",
        },
        "json_file": {
            "class": "logging.handlers.WatchedFileHandler",
            "filename": "logs/json.log",
            "formatter": "json_formatter",
        },
        "flat_line_file": {
            "class": "logging.handlers.WatchedFileHandler",
            "filename": "logs/flat_line.log",
            "formatter": "key_value",
        },
    },
    "loggers": {
        "django_structlog": {
            "handlers": ["console", "flat_line_file", "json_file"],
            "level": "INFO",
        },
        "django_structlog_demo_project": {
            "handlers": ["console", "flat_line_file", "json_file"],
            "level": "INFO",
        },
    }
}

structlog.configure(
    processors=[
        structlog.stdlib.filter_by_level,
        structlog.processors.TimeStamper(fmt="iso"),
        structlog.stdlib.add_logger_name,
        structlog.stdlib.add_log_level,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.StackInfoRenderer(),
        structlog.processors.format_exc_info,
        structlog.processors.UnicodeDecoder(),
        structlog.processors.ExceptionPrettyPrinter(),
        structlog.stdlib.ProcessorFormatter.wrap_for_formatter,
    ],
    context_class=structlog.threadlocal.wrap_dict(dict),
    logger_factory=structlog.stdlib.LoggerFactory(),
    wrapper_class=structlog.stdlib.BoundLogger,
    cache_logger_on_first_use=True,
)

Start logging with structlog instead of logging.

import structlog
logger = structlog.get_logger(__name__)

Extending Request Log Metadata

By default only a request_id and the user_id are bound from the request but pertinent log metadata may vary from a project to another.

If you need to add more metadata from the request you can implement a convenient signal receiver to bind them.

from django.dispatch import receiver

from django_structlog.signals import bind_extra_request_metadata


@receiver(bind_extra_request_metadata)
def bind_user_email(request, logger, **kwargs):
    logger.bind(user_email=getattr(request.user, 'email', ''))

Example outputs

Flat lines file (logs/flat_lines.log)

timestamp='2019-04-13T19:39:29.321453Z' level='info' event='request_started' logger='django_structlog.middlewares.request' request_id='c53dff1d-3fc5-4257-a78a-9a567c937561' user_id=1 ip='0.0.0.0' request=<WSGIRequest: GET '/'> user_agent='Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36'
timestamp='2019-04-13T19:39:29.345207Z' level='info' event='request_finished' logger='django_structlog.middlewares.request' request_id='c53dff1d-3fc5-4257-a78a-9a567c937561' user_id=1 ip='0.0.0.0' code=200
timestamp='2019-04-13T19:39:31.086155Z' level='info' event='request_started' logger='django_structlog.middlewares.request' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0' request=<WSGIRequest: POST '/success_task'> user_agent='Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36'
timestamp='2019-04-13T19:39:31.089925Z' level='info' event='Enqueuing successful task' logger='django_structlog_demo_project.home.views' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0'
timestamp='2019-04-13T19:39:31.147590Z' level='info' event='task_enqueued' logger='django_structlog.middlewares.celery' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0' task_id='6b11fd80-3cdf-4de5-acc2-3fd4633aa654'
timestamp='2019-04-13T19:39:31.153081Z' level='info' event='This is a successful task' logger='django_structlog_demo_project.taskapp.celery' task_id='6b11fd80-3cdf-4de5-acc2-3fd4633aa654' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0'
timestamp='2019-04-13T19:39:31.160043Z' level='info' event='request_finished' logger='django_structlog.middlewares.request' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0' code=201
timestamp='2019-04-13T19:39:31.162372Z' level='info' event='task_succeed' logger='django_structlog.middlewares.celery' task_id='6b11fd80-3cdf-4de5-acc2-3fd4633aa654' request_id='3a8f801c-072b-4805-8f38-e1337f363ed4' user_id=1 ip='0.0.0.0' result='None'

Json file (logs/json.log)

{"request_id": "c53dff1d-3fc5-4257-a78a-9a567c937561", "user_id": 1, "ip": "0.0.0.0", "request": "<WSGIRequest: GET '/'>", "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36", "event": "request_started", "timestamp": "2019-04-13T19:39:29.321453Z", "logger": "django_structlog.middlewares.request", "level": "info"}
{"request_id": "c53dff1d-3fc5-4257-a78a-9a567c937561", "user_id": 1, "ip": "0.0.0.0", "code": 200, "event": "request_finished", "timestamp": "2019-04-13T19:39:29.345207Z", "logger": "django_structlog.middlewares.request", "level": "info"}
{"request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "request": "<WSGIRequest: POST '/success_task'>", "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36", "event": "request_started", "timestamp": "2019-04-13T19:39:31.086155Z", "logger": "django_structlog.middlewares.request", "level": "info"}
{"request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "event": "Enqueuing successful task", "timestamp": "2019-04-13T19:39:31.089925Z", "logger": "django_structlog_demo_project.home.views", "level": "info"}
{"request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "task_id": "6b11fd80-3cdf-4de5-acc2-3fd4633aa654", "event": "task_enqueued", "timestamp": "2019-04-13T19:39:31.147590Z", "logger": "django_structlog.middlewares.celery", "level": "info"}
{"task_id": "6b11fd80-3cdf-4de5-acc2-3fd4633aa654", "request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "event": "This is a successful task", "timestamp": "2019-04-13T19:39:31.153081Z", "logger": "django_structlog_demo_project.taskapp.celery", "level": "info"}
{"request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "code": 201, "event": "request_finished", "timestamp": "2019-04-13T19:39:31.160043Z", "logger": "django_structlog.middlewares.request", "level": "info"}
{"task_id": "6b11fd80-3cdf-4de5-acc2-3fd4633aa654", "request_id": "3a8f801c-072b-4805-8f38-e1337f363ed4", "user_id": 1, "ip": "0.0.0.0", "result": "None", "event": "task_succeed", "timestamp": "2019-04-13T19:39:31.162372Z", "logger": "django_structlog.middlewares.celery", "level": "info"}

Running the tests

Note: For the moment redis is needed to run the tests. The easiest way start docker’s demo.

docker-compose up --build

In another shell

pip install -r requirements/base.txt
pytest

Demo app

docker-compose up --build

Open http://0.0.0.0:8000/ in your browser.

Navigate while looking into the log files and shell’s output.

Authors

• Jules Robichaud-Gagnon - Initial work - jrobichaud

See also the list of contributors who participated in this project.

Acknowledgments

• Big thanks to @ferd for his bad opinions that inspired the author enough to spend time on this library.

• This issue helped the author to figure out how to integrate structlog in Django.

License

This project is licensed under the MIT License - see the LICENSE file for details