This is an exhaustive list of settings for Gunicorn. Some settings are only able to be set from a configuration file. The setting name is what should be used in the configuration file. The command line arguments are listed as well for reference on setting at the command line.
Note
Settings can be specified by using environment variable
GUNICORN_CMD_ARGS
. All available command line arguments can be used.
For example, to specify the bind address and number of workers:
$ GUNICORN_CMD_ARGS="--bind=127.0.0.1 --workers=3" gunicorn app:app
.. versionadded:: 19.7
-c CONFIG, --config CONFIG
None
The Gunicorn config file.
A string of the form PATH
, file:PATH
, or python:MODULE_NAME
.
Only has an effect when specified on the command line or as part of an application specific configuration.
.. versionchanged:: 19.4 Loading the config from a Python module requires the ``python:`` prefix.
--reload
False
Restart workers when code changes.
This setting is intended for development. It will cause workers to be restarted whenever application code changes.
The reloader is incompatible with application preloading. When using a paste configuration be sure that the server block does not import any application code or the reload will not work as designed.
The default behavior is to attempt inotify with a fallback to file system polling. Generally, inotify should be preferred if available because it consumes less system resources.
Note
In order to use the inotify reloader, you must have the inotify
package installed.
--reload-engine STRING
auto
The implementation that should be used to power :ref:`reload`.
Valid engines are:
- 'auto'
- 'poll'
- 'inotify' (requires inotify)
.. versionadded:: 19.7
--reload-extra-file FILES
[]
Extends :ref:`reload` option to also watch and reload on additional files (e.g., templates, configurations, specifications, etc.).
.. versionadded:: 19.8
--spew
False
Install a trace function that spews every line executed by the server.
This is the nuclear option.
--check-config
False
Check the configuration.
--access-logfile FILE
None
The Access log file to write to.
'-'
means log to stdout.
--disable-redirect-access-to-syslog
False
Disable redirect access logs to syslog.
.. versionadded:: 19.8
--access-logformat STRING
%(h)s %(l)s %(u)s %(t)s "%(r)s" %(s)s %(b)s "%(f)s" "%(a)s"
The access log format.
Identifier | Description |
---|---|
h | remote address |
l | '-' |
u | user name |
t | date of the request |
r | status line (e.g. GET / HTTP/1.1 ) |
m | request method |
U | URL path without query string |
q | query string |
H | protocol |
s | status |
B | response length |
b | response length or '-' (CLF format) |
f | referer |
a | user agent |
T | request time in seconds |
D | request time in microseconds |
L | request time in decimal seconds |
p | process ID |
{Header}i | request header |
{Header}o | response header |
{Variable}e | environment variable |
--error-logfile FILE, --log-file FILE
-
The Error log file to write to.
Using '-'
for FILE makes gunicorn log to stderr.
.. versionchanged:: 19.2 Log to stderr by default.
--log-level LEVEL
info
The granularity of Error log outputs.
Valid level names are:
- debug
- info
- warning
- error
- critical
--capture-output
False
Redirect stdout/stderr to specified file in :ref:`errorlog`.
.. versionadded:: 19.6
--logger-class STRING
gunicorn.glogging.Logger
The logger you want to use to log events in Gunicorn.
The default class (gunicorn.glogging.Logger
) handle most of
normal usages in logging. It provides error and access logging.
You can provide your own logger by giving Gunicorn a
Python path to a subclass like gunicorn.glogging.Logger
.
--log-config FILE
None
The log config file to use. Gunicorn uses the standard Python logging module's Configuration file format.
--log-config-dict
{}
The log config dictionary to use, using the standard Python logging module's dictionary configuration format. This option takes precedence over the :ref:`logconfig` option, which uses the older file configuration format.
Format: https://docs.python.org/3/library/logging.config.html#logging.config.dictConfig
.. versionadded:: 19.8
--log-syslog-to SYSLOG_ADDR
unix:///var/run/syslog
Address to send syslog messages.
Address is a string of the form:
unix://PATH#TYPE
: for unix domain socket.TYPE
can bestream
for the stream driver ordgram
for the dgram driver.stream
is the default.udp://HOST:PORT
: for UDP socketstcp://HOST:PORT
: for TCP sockets
--log-syslog
False
Send Gunicorn logs to syslog.
.. versionchanged:: 19.8 You can now disable sending access logs by using the :ref:`disable-redirect-access-to-syslog` setting.
--log-syslog-prefix SYSLOG_PREFIX
None
Makes Gunicorn use the parameter as program-name in the syslog entries.
All entries will be prefixed by gunicorn.<prefix>
. By default the
program name is the name of the process.
--log-syslog-facility SYSLOG_FACILITY
user
Syslog facility name
-R, --enable-stdio-inheritance
False
Enable stdio inheritance.
Enable inheritance for stdio file descriptors in daemon mode.
Note: To disable the Python stdout buffering, you can to set the user
environment variable PYTHONUNBUFFERED
.
--statsd-host STATSD_ADDR
None
host:port
of the statsd server to log to.
.. versionadded:: 19.1
--statsd-prefix STATSD_PREFIX
(empty string)
Prefix to use when emitting statsd metrics (a trailing .
is added,
if not provided).
.. versionadded:: 19.2
-n STRING, --name STRING
None
A base to use with setproctitle for process naming.
This affects things like ps
and top
. If you're going to be
running more than one instance of Gunicorn you'll probably want to set a
name to tell them apart. This requires that you install the setproctitle
module.
If not set, the default_proc_name setting will be used.
gunicorn
Internal setting that is adjusted for each type of application.
--keyfile FILE
None
SSL key file
--certfile FILE
None
SSL certificate file
--ssl-version
_SSLMethod.PROTOCOL_TLS
SSL version to use (see stdlib ssl module's)
.. versionchanged:: 19.7 The default value has been changed from ``ssl.PROTOCOL_TLSv1`` to ``ssl.PROTOCOL_SSLv23``.
--cert-reqs
VerifyMode.CERT_NONE
Whether client certificate is required (see stdlib ssl module's)
--ca-certs FILE
None
CA certificates file
--suppress-ragged-eofs
True
Suppress ragged EOFs (see stdlib ssl module's)
--do-handshake-on-connect
False
Whether to perform SSL handshake on socket connect (see stdlib ssl module's)
--ciphers
TLSv1
Ciphers to use (see stdlib ssl module's)
--limit-request-line INT
4094
The maximum size of HTTP request line in bytes.
This parameter is used to limit the allowed size of a client's HTTP request-line. Since the request-line consists of the HTTP method, URI, and protocol version, this directive places a restriction on the length of a request-URI allowed for a request on the server. A server needs this value to be large enough to hold any of its resource names, including any information that might be passed in the query part of a GET request. Value is a number from 0 (unlimited) to 8190.
This parameter can be used to prevent any DDOS attack.
--limit-request-fields INT
100
Limit the number of HTTP headers fields in a request.
This parameter is used to limit the number of headers in a request to prevent DDOS attack. Used with the limit_request_field_size it allows more safety. By default this value is 100 and can't be larger than 32768.
--limit-request-field_size INT
8190
Limit the allowed size of an HTTP request header field.
Value is a positive number or 0. Setting it to 0 will allow unlimited header field sizes.
Warning
Setting this parameter to a very high or unlimited value can open up for DDOS attacks.
def on_starting(server): pass
Called just before the master process is initialized.
The callable needs to accept a single instance variable for the Arbiter.
def on_reload(server): pass
Called to recycle workers during a reload via SIGHUP.
The callable needs to accept a single instance variable for the Arbiter.
def when_ready(server): pass
Called just after the server is started.
The callable needs to accept a single instance variable for the Arbiter.
def pre_fork(server, worker): pass
Called just before a worker is forked.
The callable needs to accept two instance variables for the Arbiter and new Worker.
def post_fork(server, worker): pass
Called just after a worker has been forked.
The callable needs to accept two instance variables for the Arbiter and new Worker.
def post_worker_init(worker): pass
Called just after a worker has initialized the application.
The callable needs to accept one instance variable for the initialized Worker.
def worker_int(worker): pass
Called just after a worker exited on SIGINT or SIGQUIT.
The callable needs to accept one instance variable for the initialized Worker.
def worker_abort(worker): pass
Called when a worker received the SIGABRT signal.
This call generally happens on timeout.
The callable needs to accept one instance variable for the initialized Worker.
def pre_exec(server): pass
Called just before a new master process is forked.
The callable needs to accept a single instance variable for the Arbiter.
def pre_request(worker, req): worker.log.debug("%s %s" % (req.method, req.path))
Called just before a worker processes the request.
The callable needs to accept two instance variables for the Worker and the Request.
def post_request(worker, req, environ, resp): pass
Called after a worker processes the request.
The callable needs to accept two instance variables for the Worker and the Request.
def child_exit(server, worker): pass
Called just after a worker has been exited, in the master process.
The callable needs to accept two instance variables for the Arbiter and the just-exited Worker.
.. versionadded:: 19.7
def worker_exit(server, worker): pass
Called just after a worker has been exited, in the worker process.
The callable needs to accept two instance variables for the Arbiter and the just-exited Worker.
def nworkers_changed(server, new_value, old_value): pass
Called just after num_workers has been changed.
The callable needs to accept an instance variable of the Arbiter and two integers of number of workers after and before change.
If the number of workers is set for the first time, old_value would
be None
.
def on_exit(server): pass
Called just before exiting Gunicorn.
The callable needs to accept a single instance variable for the Arbiter.
--preload
False
Load application code before the worker processes are forked.
By preloading an application you can save some RAM resources as well as speed up server boot times. Although, if you defer application loading to each worker process, you can reload your application code easily by restarting workers.
--no-sendfile
None
Disables the use of sendfile()
.
If not set, the value of the SENDFILE
environment variable is used
to enable or disable its usage.
.. versionadded:: 19.2
.. versionchanged:: 19.4 Swapped ``--sendfile`` with ``--no-sendfile`` to actually allow disabling.
.. versionchanged:: 19.6 added support for the ``SENDFILE`` environment variable
--reuse-port
False
Set the SO_REUSEPORT
flag on the listening socket.
.. versionadded:: 19.8
--chdir
/usr/src/app
Chdir to specified directory before apps loading.
-D, --daemon
False
Daemonize the Gunicorn process.
Detaches the server from the controlling terminal and enters the background.
-e ENV, --env ENV
[]
Set environment variable (key=value).
Pass variables to the execution environment. Ex.:
$ gunicorn -b 127.0.0.1:8000 --env FOO=1 test:app
and test for the foo variable environment in your application.
-p FILE, --pid FILE
None
A filename to use for the PID file.
If not set, no PID file will be written.
--worker-tmp-dir DIR
None
A directory to use for the worker heartbeat temporary file.
If not set, the default temporary directory will be used.
Note
The current heartbeat system involves calling os.fchmod
on
temporary file handlers and may block a worker for arbitrary time
if the directory is on a disk-backed filesystem.
See :ref:`blocking-os-fchmod` for more detailed information and a solution for avoiding this problem.
-u USER, --user USER
501
Switch worker processes to run as this user.
A valid user id (as an integer) or the name of a user that can be
retrieved with a call to pwd.getpwnam(value)
or None
to not
change the worker process user.
-g GROUP, --group GROUP
20
Switch worker process to run as this group.
A valid group id (as an integer) or the name of a user that can be
retrieved with a call to pwd.getgrnam(value)
or None
to not
change the worker processes group.
-m INT, --umask INT
0
A bit mask for the file mode on files written by Gunicorn.
Note that this affects unix socket permissions.
A valid value for the os.umask(mode)
call or a string compatible
with int(value, 0)
(0
means Python guesses the base, so values
like 0
, 0xFF
, 0022
are valid for decimal, hex, and octal
representations)
--initgroups
False
If true, set the worker process's group access list with all of the groups of which the specified username is a member, plus the specified group id.
.. versionadded:: 19.7
None
Directory to store temporary request data as they are read.
This may disappear in the near future.
This path should be writable by the process permissions set for Gunicorn workers. If not specified, Gunicorn will choose a system generated temporary directory.
{'X-FORWARDED-PROTOCOL': 'ssl', 'X-FORWARDED-PROTO': 'https', 'X-FORWARDED-SSL': 'on'}
A dictionary containing headers and values that the front-end proxy
uses to indicate HTTPS requests. These tell Gunicorn to set
wsgi.url_scheme
to https
, so your application can tell that the
request is secure.
The dictionary should map upper-case header names to exact string values. The value comparisons are case-sensitive, unlike the header names, so make sure they're exactly what your front-end proxy sends when handling HTTPS requests.
It is important that your front-end proxy configuration ensures that the headers defined here can not be passed directly from the client.
--forwarded-allow-ips STRING
127.0.0.1
Front-end's IPs from which allowed to handle set secure headers. (comma separate).
Set to *
to disable checking of Front-end IPs (useful for setups
where you don't know in advance the IP address of Front-end, but
you still trust the environment).
By default, the value of the FORWARDED_ALLOW_IPS
environment
variable. If it is not defined, the default is "127.0.0.1"
.
--pythonpath STRING
None
A comma-separated list of directories to add to the Python path.
e.g.
'/home/djangoprojects/myproject,/home/python/mylibrary'
.
--paste STRING, --paster STRING
None
Load a PasteDeploy config file. The argument may contain a #
symbol followed by the name of an app section from the config file,
e.g. production.ini#admin
.
At this time, using alternate server blocks is not supported. Use the command line arguments to control server configuration instead.
--proxy-protocol
False
Enable detect PROXY protocol (PROXY mode).
Allow using HTTP and Proxy together. It may be useful for work with stunnel as HTTPS frontend and Gunicorn as HTTP server.
PROXY protocol: http://haproxy.1wt.eu/download/1.5/doc/proxy-protocol.txt
Example for stunnel config:
[https] protocol = proxy accept = 443 connect = 80 cert = /etc/ssl/certs/stunnel.pem key = /etc/ssl/certs/stunnel.key
--proxy-allow-from
127.0.0.1
Front-end's IPs from which allowed accept proxy requests (comma separate).
Set to *
to disable checking of Front-end IPs (useful for setups
where you don't know in advance the IP address of Front-end, but
you still trust the environment)
--paste-global CONF
[]
Set a PasteDeploy global config variable in key=value
form.
The option can be specified multiple times.
The variables are passed to the the PasteDeploy entrypoint. Example:
$ gunicorn -b 127.0.0.1:8000 --paste development.ini --paste-global FOO=1 --paste-global BAR=2
.. versionadded:: 19.7
-b ADDRESS, --bind ADDRESS
['127.0.0.1:8000']
The socket to bind.
A string of the form: HOST
, HOST:PORT
, unix:PATH
. An IP is
a valid HOST
.
Multiple addresses can be bound. ex.:
$ gunicorn -b 127.0.0.1:8000 -b [::1]:8000 test:app
will bind the test:app application on localhost both on ipv6 and ipv4 interfaces.
--backlog INT
2048
The maximum number of pending connections.
This refers to the number of clients that can be waiting to be served. Exceeding this number results in the client getting an error when attempting to connect. It should only affect servers under significant load.
Must be a positive integer. Generally set in the 64-2048 range.
-w INT, --workers INT
1
The number of worker processes for handling requests.
A positive integer generally in the 2-4 x $(NUM_CORES)
range.
You'll want to vary this a bit to find the best for your particular
application's work load.
By default, the value of the WEB_CONCURRENCY
environment variable.
If it is not defined, the default is 1
.
-k STRING, --worker-class STRING
sync
The type of workers to use.
The default class (sync
) should handle most "normal" types of
workloads. You'll want to read :doc:`design` for information on when
you might want to choose one of the other worker classes. Required
libraries may be installed using setuptools' extra_require
feature.
A string referring to one of the following bundled classes:
sync
eventlet
- Requires eventlet >= 0.9.7 (or install it viapip install gunicorn[eventlet]
)gevent
- Requires gevent >= 0.13 (or install it viapip install gunicorn[gevent]
)tornado
- Requires tornado >= 0.2 (or install it viapip install gunicorn[tornado]
)gthread
- Python 2 requires the futures package to be installed (or install it viapip install gunicorn[gthread]
)gaiohttp
- Deprecated.
Optionally, you can provide your own worker by giving Gunicorn a
Python path to a subclass of gunicorn.workers.base.Worker
.
This alternative syntax will load the gevent class:
gunicorn.workers.ggevent.GeventWorker
.
.. deprecated:: 19.8 The ``gaiohttp`` worker is deprecated. Please use ``aiohttp.worker.GunicornWebWorker`` instead. See :ref:`asyncio-workers` for more information on how to use it.
--threads INT
1
The number of worker threads for handling requests.
Run each worker with the specified number of threads.
A positive integer generally in the 2-4 x $(NUM_CORES)
range.
You'll want to vary this a bit to find the best for your particular
application's work load.
If it is not defined, the default is 1
.
This setting only affects the Gthread worker type.
Note
If you try to use the sync
worker type and set the threads
setting to more than 1, the gthread
worker type will be used
instead.
--worker-connections INT
1000
The maximum number of simultaneous clients.
This setting only affects the Eventlet and Gevent worker types.
--max-requests INT
0
The maximum number of requests a worker will process before restarting.
Any value greater than zero will limit the number of requests a work will process before automatically restarting. This is a simple method to help limit the damage of memory leaks.
If this is set to zero (the default) then the automatic worker restarts are disabled.
--max-requests-jitter INT
0
The maximum jitter to add to the max_requests setting.
The jitter causes the restart per worker to be randomized by
randint(0, max_requests_jitter)
. This is intended to stagger worker
restarts to avoid all workers restarting at the same time.
.. versionadded:: 19.2
-t INT, --timeout INT
30
Workers silent for more than this many seconds are killed and restarted.
Generally set to thirty seconds. Only set this noticeably higher if you're sure of the repercussions for sync workers. For the non sync workers it just means that the worker process is still communicating and is not tied to the length of time required to handle a single request.
--graceful-timeout INT
30
Timeout for graceful workers restart.
After receiving a restart signal, workers have this much time to finish serving requests. Workers still alive after the timeout (starting from the receipt of the restart signal) are force killed.
--keep-alive INT
2
The number of seconds to wait for requests on a Keep-Alive connection.
Generally set in the 1-5 seconds range for servers with direct connection to the client (e.g. when you don't have separate load balancer). When Gunicorn is deployed behind a load balancer, it often makes sense to set this to a higher value.
Note
sync
worker does not support persistent connections and will
ignore this option.