prometheus-flask-exporter 0.0.9

Prometheus metrics exporter for Flask

Prometheus Flask exporter
=========================

|Travis| |PyPI| |PyPI| |Coverage Status| |Code Climate|

This library provides HTTP request metrics to export into
`Prometheus <https://prometheus.io/>`__. It can also track method
invocations using convenient functions.

Usage
-----

.. code:: python

from flask import Flask, request
from prometheus_flask_exporter import PrometheusMetrics

app = Flask(__name__)
metrics = PrometheusMetrics(app)

# static information as metric
metrics.info('app_info', 'Application info', version='1.0.3')

@app.route('/')
def main():
pass # requests tracked by default

@app.route('/skip')
@metrics.do_not_track()
def skip():
pass # default metrics are not collected

@app.route('/<item_type>')
@metrics.do_not_track()
@metrics.counter('invocation_by_type', 'Number of invocations by type',
labels={'item_type': lambda: request.view_args['type']})
def by_type(item_type):
pass # only the counter is collected, not the default metrics

@app.route('/long-running')
@metrics.gauge('in_progress', 'Long running requests in progress')
def long_running():
pass

@app.route('/status/<int:status>')
@metrics.do_not_track()
@metrics.summary('requests_by_status', 'Request latencies by status',
labels={'status': lambda r: r.status_code})
@metrics.histogram('requests_by_status_and_path', 'Request latencies by status and path',
labels={'status': lambda r: r.status_code, 'path': lambda: request.path})
def echo_status(status):
return 'Status: %s' % status, status

Default metrics
---------------

The following metrics are exported by default (unless the
``export_defaults`` is set to ``False``).

- ``flask_http_request_duration_seconds`` (Histogram)
Labels: ``method``, ``path`` and ``status``.
Flask HTTP request duration in seconds for all Flask requests.
- ``flask_http_request_total`` (Counter)
Labels: ``method`` and ``status``. Total number of HTTP requests for
all Flask requests.
- ``flask_exporter_info`` (Gauge)
Information about the Prometheus Flask exporter itself (e.g.
``version``).

Labels
~~~~~~

When defining labels for metrics on functions, the following values are
supported in the dictionary:

- A simple static value
- A no-argument callable
- A single argument callable that will receive the Flask response as
the argument

Label values are evaluated within the request context.

Application information
~~~~~~~~~~~~~~~~~~~~~~~

The ``PrometheusMetrics.info(..)`` method provides a way to expose
information as a ``Gauge`` metric, the application version for example.

The metric is returned from the method to allow changing its value from
the default ``1``:

.. code:: python

metrics = PrometheusMetrics(app)
info = metrics.info('dynamic_info', 'Something dynamic')
...
info.set(42.1)

License
-------

MIT

.. |Travis| image:: https://img.shields.io/travis/rycus86/prometheus_flask_exporter.svg
:target: https://travis-ci.org/rycus86/prometheus_flask_exporter
.. |PyPI| image:: https://img.shields.io/pypi/v/prometheus-flask-exporter.svg
:target: https://pypi.python.org/pypi/prometheus-flask-exporter
.. |PyPI| image:: https://img.shields.io/pypi/pyversions/prometheus-flask-exporter.svg
:target: https://pypi.python.org/pypi/prometheus-flask-exporter
.. |Coverage Status| image:: https://coveralls.io/repos/github/rycus86/prometheus_flask_exporter/badge.svg?branch=master
:target: https://coveralls.io/github/rycus86/prometheus_flask_exporter?branch=master
.. |Code Climate| image:: https://codeclimate.com/github/rycus86/prometheus_flask_exporter/badges/gpa.svg
:target: https://codeclimate.com/github/rycus86/prometheus_flask_exporter