You can run Gunicorn by using commands or integrate with popular frameworks like Django, Pyramid, or TurboGears. For deploying Gunicorn in production see Deploying Gunicorn.
After installing Gunicorn you will have access to the command line script
$ gunicorn [OPTIONS] [WSGI_APP]
WSGI_APP is of the pattern
module name can be a full dotted path. The variable name refers to a WSGI
callable that should be found in the specified module.
Changed in version 20.1.0:
WSGI_APP is optional if it is defined in a config file.
Example with the test app:
def app(environ, start_response): """Simplest possible application object""" data = b'Hello, World!\n' status = '200 OK' response_headers = [ ('Content-type', 'text/plain'), ('Content-Length', str(len(data))) ] start_response(status, response_headers) return iter([data])
You can now run the app with the following command:
$ gunicorn --workers=2 test:app
The variable name can also be a function call. In that case the name will be imported from the module, then called to get the application object. This is commonly referred to as the “application factory” pattern.
def create_app(): app = FrameworkApp() ... return app
$ gunicorn --workers=2 'test:create_app()'
Positional and keyword arguments can also be passed, but it is recommended to load configuration from environment variables rather than the command line.
Commonly Used Arguments¶
-c CONFIG, --config=CONFIG- Specify a config file in the form
-b BIND, --bind=BIND- Specify a server socket to bind. Server sockets can be any of
unix:$(PATH). An IP is a valid
-w WORKERS, --workers=WORKERS- The number of worker processes. This number should generally be between 2-4 workers per core in the server. Check the FAQ for ideas on tuning this parameter.
-k WORKERCLASS, --worker-class=WORKERCLASS- The type of worker process to run. You’ll definitely want to read the production page for the implications of this parameter. You can set this to
$(NAME)is one of
syncis the default. See the worker_class documentation for more information.
-n APP_NAME, --name=APP_NAME- If setproctitle is installed you can adjust the name of Gunicorn process as they appear in the process system table (which affects tools like
Settings can be specified by using environment variable GUNICORN_CMD_ARGS.
Gunicorn also provides integration for Django and Paste Deploy applications.
Gunicorn will look for a WSGI callable named
application if not specified.
So for a typical Django project, invoking Gunicorn would look like:
$ gunicorn myproject.wsgi
This requires that your project be on the Python path; the simplest way to
ensure that is to run this command from the same directory as your
$ gunicorn --env DJANGO_SETTINGS_MODULE=myproject.settings myproject.wsgi
Frameworks such as Pyramid and Turbogears are typically configured using Paste Deployment configuration files. If you would like to use these files with Gunicorn, there are two approaches.
As a server runner, Gunicorn can serve your application using the commands from
your framework, such as
gearbox. To use Gunicorn with these
commands, specify it as a server in your configuration file:
[server:main] use = egg:gunicorn#main host = 127.0.0.1 port = 8080 workers = 3
This approach is the quickest way to get started with Gunicorn, but there are
some limitations. Gunicorn will have no control over how the application is
loaded, so settings such as reload will have no effect and Gunicorn will be
unable to hot upgrade a running application. Using the daemon option may
confuse your command line tool. Instead, use the built-in support for these
features provided by that tool. For example, run
pserve --reload instead of
reload = True in the server configuration block. For advanced
configuration of Gunicorn, such as Server Hooks specifying a Gunicorn
configuration file using the
config key is supported.
To use the full power of Gunicorn’s reloading and hot code upgrades, use the paste option to run your application instead. When used this way, Gunicorn will use the application defined by the PasteDeploy configuration file, but Gunicorn will not use any server configuration defined in the file. Instead, configure gunicorn.
$ gunicorn --paste development.ini -b :8080 --chdir /path/to/project
Or use a different application:
$ gunicorn --paste development.ini#admin -b :8080 --chdir /path/to/project
With both approaches, Gunicorn will use any loggers section found in Paste Deployment configuration file, unless instructed otherwise by specifying additional logging settings.