Flask-Log-Request-Id

|CircleCI|

Flask-Log-Request-Id is an extension for Flask_ that can parse and handle the request-id sent by request processors like Amazon ELB, Heroku Request-ID or any multi-tier infrastructure as the one used at microservices. A common usage scenario is to inject the request_id in the logging system so that all log records, even those emitted by third party libraries, have attached the request_id that initiated their call. This can greatly improve tracing and debugging of problems.

Features

Flask-Log-Request-Id provides the current_request_id() function which can be used at any time to get the request id of the initiated execution chain. It also comes with log filter to inject this information on log events as also an extension to forward the current request id into Celery's workers.

Example: Parse request id and send it to to logging

In the following example, we will use the ``RequestIDLogFilter`` to inject
the request id on all log events, and a custom formatter to print this
information. If all these sounds unfamiliar please take a look at `python logging system`_

.. code:: python

    import logging
    import logging.config
    from random import randint
    from flask import Flask
    from flask_log_request_id import RequestID, RequestIDLogFilter

    def generic_add(a, b):
        """Simple function to add two numbers that is not aware of the request id"""
        logging.debug('Called generic_add({}, {})'.format(a, b))
        return a + b

    app = Flask(__name__)
    RequestID(app)

    # Setup logging
    handler = logging.StreamHandler()
    handler.setFormatter(
        logging.Formatter("%(asctime)s - %(name)s - level=%(levelname)s - request_id=%(request_id)s - %(message)s"))
    handler.addFilter(RequestIDLogFilter())  # << Add request id contextual filter
    logging.getLogger().addHandler(handler)


    @app.route('/')
    def index():
        a, b = randint(1, 15), randint(1, 15)
        logging.info('Adding two random numbers {} {}'.format(a, b))
        return str(generic_add(a, b))


Installation
------------
The easiest way to install it is using ``pip`` from PyPI

.. code:: bash

    pip install flask-log-request-id


License
-------

See the `LICENSE`_ file for license rights and limitations (MIT).


.. _Flask: http://flask.pocoo.org/
.. _Amazon ELB: http://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-request-tracing.html
.. _Heroku Request-ID: https://devcenter.heroku.com/articles/http-request-id
.. _python logging system: https://docs.python.org/3/library/logging.html
.. _LICENSE: https://github.com/Workable/flask-log-request-id/blob/master/LICENSE.md
.. |CircleCI| image:: https://img.shields.io/circleci/project/github/Workable/flask-log-request-id.svg
   :target: https://circleci.com/gh/Workable/flask-log-request-id