paylogic / Wsgi Statsd
Programming Languages
wsgi-statsd documentation
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wsgi_statsd is a WSGI middleware that provides an easy way to time all requests. Integration is as easy as just wrapping your existing wsgi application.
.. contents::
Usage
In your wsgi.py file wrap your WSGI application as follows:
.. code-block:: python
import statsd
from wsgi_statsd import StatsdTimingMiddleware
def application(environ, start_response):
response_body = 'The request method was %s' % environ['REQUEST_METHOD']
status = '200 OK'
response_headers = [('Content-Type', 'text/plain'),
('Content-Length', str(len(response_body)))]
start_response(status, response_headers)
return [response_body]
client = statsd.StatsClient(
prefix='your_prefix',
host='your_host',
port=8125
)
application = StatsdTimingMiddleware(application, client)
.. note::
If an unhandled exception happens, it will not be timed by default.
This is a design decision to separate error reporting and actual statistical measurements.
To enable exception timing, pass `time_exception=True` to the middleware constructor:
.. code-block:: python
application = StatsdTimingMiddleware(application, client, time_exceptions=True)
What it does
wsgi-statsd uses the statsd timer function, generates a key and sets the amount of time the request took as the value. The key is constructed as follows:
<statsd-client-prefix>.<separator-joined-path>.<request-method>.<response-code>.<exception-name>
Using the foo
prefix, in your statsd client, and calling the www.spam.com/bar/test/
page will result in foo .bar_test.GET.200
having a value equal to the time it took to handle the request.
If you passed time_exceptions=True
and any exception occurs during the response, then the key name will be postfixed
with the exception class name: foo.bar_test.GET.500.ValueError
.
Customizing for your needs
It's possible to customize the way wsgi_statsd
generates the key and/or time. StatsdTimingMiddleware
has
send_stats
and get_key_name
which you can override:
.. code-block:: python
class CustomStatsdMiddleware(StatsdTimingMiddleware):
def get_key_name(self, environ, response_interception):
return super(self, CustomStatsdMiddleware).get_key_name(environ, response_interception) + '.' + environ['Transfer-Encoding']
def send_stats(self, start, environ, response_interception):
super(self, CustomStatsdMiddleware).send_stats(start + 10, environ, response_interception)
wsgi-statsd uses underscores as a separator for the path part of the key that is sent to statsd as that makes it
easy to retrieve the data from graphite. You can override this default by passing a separator
value to the
middleware constructor:
.. code-block:: python
StatsdTimingMiddleware(application, client, separator='.')
Contact
If you have questions, bug reports, suggestions, etc. please create an issue on
the GitHub project page <http://github.com/paylogic/wsgi-statsd>
_.
License
This software is licensed under the MIT license <http://en.wikipedia.org/wiki/MIT_License>
_.
Please refer to the license file <https://github.com/paylogic/wsgi-statsd/blob/master/LICENSE.txt>
_.
© 2015 Wouter Lansu, Paylogic International and others.