The Configuration File

Gunicorn 0.5 introduced the ability to use a Python configuration file. Gunicorn will look for gunicorn.conf.py in the current working directory or what ever path is specified on the command line with the -c option.

Example gunicorn.conf.py

arbiter = "egg:gunicorn"    # The arbiter to use for worker management
backlog = 2048              # The listen queue size for the server socket
bind = "127.0.0.1:8000"     # Or "unix:/tmp/gunicorn.sock"
daemon = False              # Whether work in the background
debug = False               # Some extra logging
keepalive = 2               # Time we wait for next connection (in seconds)
logfile = "-"               # Name of the log file
loglevel = "info"           # The level at which to log
pidfile = None              # Path to a PID file
workers = 1                 # Number of workers to initialize
umask = 0                   # Umask to set when daemonizing
user = None                 # Change process owner to user
group = None                # Change process group to group
proc_name = None            # Change the process name
tmp_upload_dir = None       # Set path used to store temporary uploads
worker_connections=1000     # Maximum number of simultaneous connections

after_fork=lambda server, worker: server.log.info(
        "Worker spawned (pid: %s)" % worker.pid)

before_fork=lambda server, worker: True

before_exec=lambda server: server.log.info("Forked child, reexecuting")

Parameter Descriptions

after_fork(server, worker):
This is called by the worker after initialization.
arbiter:

The arbiter manages the worker processes that actually serve clients. It handles launching new workers and killing misbehaving workers among other things. By default the arbiter is egg:gunicorn#main. This arbiter only supports fast request handling requiring a buffering HTTP proxy.

If your application requires the ability to handle prolonged requests to provide long polling, comet, or calling an external web service you'll need to use an async arbiter. Gunicorn has two async arbiters built in using Eventlet or Gevent. You can also use the Evenlet arbiter with the Twisted helper.

backlog:
The backlog parameter defines the maximum length for the queue of pending connections. The default is 2048. See listen(2) for more information
before_fork(server, worker):
This is called by the worker just before forking.
before_exec(server):
This function is called before relaunching the master. This happens when the master receives a HUP or USR2 signal.
bind:
The address on which workers are listening. It can be a TCP address with a format of IP:PORT or a Unix socket address like unix:/path/to/socketfile.
daemon:
Whether or not to detach the server from the controlling terminal.
debug:
If True, only one worker will be launch and the variable wsgi.multiprocess will be set to False.
group:
The group in which worker processes will be launched.
keepalive:
KeepAlive timeout. The default is 2 seconds, which should be enough under most conditions for browsers to render the page and start retrieving extra elements for. Increasing this beyond 5 seconds is not recommended. Zero disables KeepAlive entirely.
logfile:
The path to the log file - (stdout) by default.
loglevel:
The level at which to log. info, debug, or error for instance. Only log messages of equal or greater severity are logged.
pidfile:
A file to store the master's PID.
proc_name:
A name for the master process. Only takes effect if setproctitle is installed. This alters the process names listed by commands like ps.
umask:
Used to set the umask when daemonizing.
user:
The user as which worker processes will by launched.
worker_connections:
Number of simultaneous connections a worker can handle when used with Eventlet or Gevent arbiter. The default is 1000.
tmp_upload_dir:
Set the path used to store temporarily the body of the request.