.. _configuring-chapter:

==================
Configuring Statsd
==================

It's easy to configure and use Statsd at runtime, but there are also two
shortcuts available.


Runtime
=======

If you are running the statsd_ server locally and on the default port,
it's extremely easy:

.. code-block:: python

    from statsd import StatsClient

    statsd = StatsClient()
    statsd.incr('foo')

There are several arguments to configure your :py:class:`StatsClient` instance.
They, and their defaults, are:

.. code-block:: python

    from statsd import StatsClient

    statsd = StatsClient(host='localhost',
                         port=8125,
                         prefix=None,
                         maxudpsize=512,
                         ipv6=False)

``host`` is the host running the statsd server. It will support any kind of
name or IP address you might use.

``port`` is the statsd server port. The default for both server and client is
``8125``.

``prefix`` helps distinguish multiple applications or environments using the
same statsd server. It will be prepended to all stats, automatically. For
example:

.. code-block:: python

    from statsd import StatsClient

    foo_stats = StatsClient(prefix='foo')
    bar_stats = StatsClient(prefix='bar')

    foo_stats.incr('baz')
    bar_stats.incr('baz')

will produce two different stats, ``foo.baz`` and ``bar.baz``. Without the
``prefix`` argument, or with the same ``prefix``, two ``StatsClient`` instances
will update the same stats.

.. versionadded:: 2.0.3

``maxudpsize`` specifies the maximum packet size statsd will use. This is an
advanced options and should not be changed unless you know what you are doing.
Larger values then the default of 512 are generally deemed unsafe for use on
the internet. On a controlled local network or when the statsd server is
running on 127.0.0.1 larger values can decrease the number of UDP packets when
pipelining many metrics. Use with care!

.. versionadded:: 3.2

``ipv6`` tells the client explicitly to look up the host using IPv6 (``True``)
or IPv4 (``False``).

.. note::

    Python will will inherently bind to an ephemeral port on all interfaces
    (`0.0.0.0`) for each configured client. This is due to the underlying
    Sockets API in the operating system/kernel. It is safe to block incoming
    traffic on your firewall if you wish.


TCP Clients
-----------

:ref:`TCP-based clients <tcp-chapter>` have an additional ``timeout`` argument,
which defaults to ``None``, and is passed to `settimeout
<https://docs.python.org/2/library/socket.html#socket.socket.settimeout>`_.


UnixSocket Clients
------------------

:ref:`UnixSocket-based clients <unix-socket-chapter>` have a single required
``socket_path`` argument instead of ``host`` and ``port``.


In Django
=========

If you are using Statsd in a Django_ application, you can configure a default
:py:class:`StatsClient` in the Django settings. All of these settings are
optional.

Here are the settings and their defaults:

.. code-block:: python

    STATSD_HOST = 'localhost'
    STATSD_PORT = 8125
    STATSD_PREFIX = None
    STATSD_MAXUDPSIZE = 512
    STATSD_IPV6 = False

You can use the default :py:class:`StatsClient` simply:

.. code-block:: python

    from statsd.defaults.django import statsd

    statsd.incr('foo')


From the Environment
====================

StatsD isn't only useful in Django or on the web. A default instance can also
be configured via environment variables.

Here are the environment variables and their defaults:

.. code-block:: bash

    STATSD_HOST=localhost
    STATSD_PORT=8125
    STATSD_PREFIX=None
    STATSD_MAXUDPSIZE=512
    STATSD_IPV6=0

and then in your Python application, you can simply do:

.. code-block:: python

    from statsd.defaults.env import statsd

    statsd.incr('foo')

.. note::

    As of version 3.0, this default instance is always available, configured
    with the default values, unless overridden by the environment.

.. _statsd: https://github.com/etsy/statsd
.. _Django: https://www.djangoproject.com/
