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Fixed #17073 - focused uwsgi docs to Django integration; thanks Preston Holmes.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17586 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Timo Graham 2012-02-24 23:24:30 +00:00
parent ce4cd788ef
commit 5a013cebd9

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@ -7,12 +7,7 @@ How to use Django with uWSGI
uWSGI_ is a fast, self-healing and developer/sysadmin-friendly application
container server coded in pure C.
It also provides a fast `caching framework`_ but its documentation is not the
purpose of this document.
.. _uWSGI: http://projects.unbit.it/uwsgi/
.. _caching framework: http://projects.unbit.it/uwsgi/wiki/CachingFramework
Prerequisite: uWSGI
===================
@ -27,89 +22,27 @@ line. For example::
# or install LTS (long term support)
pip install http://projects.unbit.it/downloads/uwsgi-lts.tar.gz
.. _installation procedures: http://projects0.unbit.it/uwsgi/wiki/Install
Prerequisite: general concept
=============================
.. _installation procedures: http://projects.unbit.it/uwsgi/wiki/Install
uWSGI model
-----------
uWSGI operates on a client-server model. Your Web server (ie. nginx, Apache)
communicates with a django-uwsgi "worker" process to serve dynamic content.
The Web server can communicate with the uWSGI process either:
See uWSGI's `background documentation`_ for more detail.
* directly by the uWSGI protocol through a socket created by uWSGI,
* or by proxying HTTP requests to the minimalist HTTP server built in uWSGI.
.. _background documentation: http://projects.unbit.it/uwsgi/wiki/Background
In the first case: the Web server can do uWSGI protocol (often with a
module). It can then use either a Unix domain socket (a "named pipe" on Win32
systems), or it can use a TCP socket. What you choose is a matterr of
preference. Usually, a TCP socket is easier because connecting to a port
doesn't require special permissions.
Configuring and starting the uWSGI server for Django
----------------------------------------------------
In the second case, the Web server doesn't need to speak the uWSGI protocol. It
just needs to be able to proxy HTTP requests to the HTTP server built-in uWSGI.
The procedure is the same as proxying to any HTTP server. Note that the Web
server is a "reverse proxy" in this case.
uWSGI supports multiple ways to configure the process, see uWSGI's
`configuration documentation`_ and `examples`_
Configuring the uWSGI server
----------------------------
.. _configuration documentation: http://projects.unbit.it/uwsgi/wiki/Doc
.. _examples: http://projects.unbit.it/uwsgi/wiki/Example
In any case, when you set up your Web server, you'll just need to point its
uwsgi or proxy module to the host/port or socket you specified when starting
the uWSGI server.
.. admonition:: Choosing the socket
The easiest is to set the socket to a high level (>49152) local port like
127.0.0.1:49152. If the socket is a file, the system administrator must
ensure that the Web server process has read, write and execute privileges
on that file.
uWSGI is highly configurable and thus there are many ways to start the
process. For example, uwsgi version 0.9.6.8 provides a hundred switches. This
guide demonstrates the most important of them, but is not a substitute the
official manual and online documentation.
uWSGI supports configuration through:
* environment variables
* command line switches
* ldap
* ini files
* xml files
* yaml files
Managing the uWSGI server
-------------------------
The system administrator controls the worker process pool by sending signals
to the master process. For example, the unix kill command sends such signals.
uWSGI can write the master process id to a "pidfile". A "pidfile" is a plain
text file containing just a process id.
Starting the server
-------------------
Starting an uWSGI server is the role of the system administrator, like
starting the Web server. It is *not* the role of the Web server to start the
uWSGI server. This means:
* the uWSGI server can be restarted or reloaded independently from the Web
server,
* (except with Cherokee), it is the role of the system administrator to make
uWSGI start on boot or reboot: either through tools like supervisor or
daemontools, either directly at init level in a file like /etc/rc.local or
/etc/conf.d/local
Managing uWSGI
==============
Starting the server
-------------------
Example command line for a Web server that understands the uWSGI protocol::
An example command to start a uWSGI server::
uwsgi --chdir=/path/to/your/project
--module='mysite.wsgi:application' \
@ -156,110 +89,8 @@ Example ini configuration file usage::
uwsgi --ini uwsgi.ini
Read more `uWSGI configuration examples
<http://projects.unbit.it/uwsgi/wiki/Example>`_.
.. admonition:: Massive application hosting
See the uWSGI docs on `managing the uWSGI process`_ for information on
starting, stoping, and reloading the uWSGI workers.
`uWSGI emperor <http://projects.unbit.it/uwsgi/wiki/Emperor>`_ is a special
uWSGI process that can manage many master processes at once.
Reloading the daemon
--------------------
As mentioned above, the uWSGI master process is one of the core components of
the uWSGI stack. The signal to brutally reload all the workers and the master
process is SIGTERM. Example command to brutally reload the uWSGI processes::
kill -TERM `cat /tmp/project-master.pid`
Patching the daemon
-------------------
One of the great advantages of uWSGI is its ability to gradually restart each
worker without losing any requests.
For example, uWSGI can be signaled that worker should reload the code after
handling their current request (if any) from bash::
# using kill to send the signal
kill -HUP `cat /tmp/project-master.pid`
# if uwsgi was started with --touch-reload=/tmp/somefile
touch /tmp/somefile
Or from Python::
uwsgi.reload()
Stopping the daemon
-------------------
If you have the process running in the foreground, it's easy enough to stop it:
Simply hitting ``Ctrl-C`` will stop and quit the uWSGI server. However, when
you're dealing with background processes, you'll need to resort to the Unix
``kill`` command.
The ``kill`` is used to send a signal to the uWSGI master process. The
`uWSGI signals are documented online
<http://projects.unbit.it/uwsgi/wiki/uWSGISignals>`_. Example command to
completely stop the uWSGI stack::
kill -INT `cat /tmp/project-master.pid`
HTTP server configuration
=========================
Nginx setup
-----------
Nginx provides the `uwsgi module <http://wiki.nginx.org/HttpUwsgiModule>`_ by
default since nginx 0.8.40. Configuring Nginx to use an uWSGI server is as
simple as setting it up to proxy requests::
location / {
uwsgi_pass 127.0.0.1:49152;
# in case of a socket file:
# uwsgi_pass unix:/tmp/yourproject.sock;
}
Note that default uwsgi parameters should be included somewhere in your Nginx
configuration. For example::
http {
include uwsgi_params;
# [...] normal nginx configuration here
}
Cherokee setup
--------------
Cherokee setup is documented in the `official Cherokee uWSGI documentation
<http://www.cherokee-project.com/doc/cookbook_uwsgi.html>`_.
Lighttpd setup
--------------
`Lighttpd uwsgi module <http://projects.unbit.it/uwsgi/wiki/RunOnLighttpd>`_ is
still experimental.
Troubleshooting
===============
As usual, the first thing to do is to check the logs. This implies:
* the web server log, which will indicate if it couldn't connect to the uWSGI
process,
* the uWSGI log, which will indicate if an exception was thrown.
Typical gotchas:
* If the socket is a file, the Web server process should have read, write and
execute permissions on the socket file. The ``--chmod-socket`` option can do
it.
* In some cases, for instance if uWSGI was started without ``--vacuum`` or
killed with ``SIGKILL``, it won't remove the socket and pidfile when it is
interrupted. It is safe to remove them manually and to start uWSGI again in
that case.
* uWSGI can start the process in the foreground, this will make errors easily
visible to the system administrator.
.. _managing the uWSGI process: http://projects.unbit.it/uwsgi/wiki/Management