We strongly recommend to use Gunicorn behind a proxy server.
Although there are many HTTP proxies available, we strongly advise that you use Nginx. If you choose another proxy server you need to make sure that it buffers slow clients when you use default Gunicorn workers. Without this buffering Gunicorn will be easily susceptible to denial-of-service attacks. You can use Boom to check if your proxy is behaving properly.
An example configuration file for fast clients with Nginx:
../../examples/nginx.conf
If you want to be able to handle streaming request/responses or other fancy features like Comet, Long polling, or Web sockets, you need to turn off the proxy buffering. When you do this you must run with one of the async worker classes.
To turn off buffering, you only need to add proxy_buffering off; to your location block:
...
location @proxy_to_app {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_buffering off;
proxy_pass http://app_server;
}
...When Nginx is handling SSL it is helpful to pass the protocol information to Gunicorn. Many web frameworks use this information to generate URLs. Without this information, the application may mistakenly generate 'http' URLs in 'https' responses, leading to mixed content warnings or broken applications. In this case, configure Nginx to pass an appropriate header:
...
proxy_set_header X-Forwarded-Proto $scheme;
...If you are running Nginx on a different host than Gunicorn you need to tell Gunicorn to trust the X-Forwarded-* headers sent by Nginx. By default, Gunicorn will only trust these headers if the connection comes from localhost. This is to prevent a malicious client from forging these headers:
$ gunicorn -w 3 --forwarded-allow-ips="10.170.3.217,10.170.3.220" test:appWhen the Gunicorn host is completely firewalled from the external network such that all connections come from a trusted proxy (e.g. Heroku) this value can be set to ''. Using this value ispotentially dangerous* if connections to Gunicorn may come from untrusted proxies or directly from clients since the application may be tricked into serving SSL-only content over an insecure connection.
Gunicorn 19 introduced a breaking change concerning how REMOTE_ADDR is handled. Previous to Gunicorn 19 this was set to the value of X-Forwarded-For if received from a trusted proxy. However, this was not in compliance with 3875 which is why the REMOTE_ADDR is now the IP address of the proxy and not the actual user. You should instead configure Nginx to send the user's IP address through the X-Forwarded-For header like this:
...
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
...It is also worth noting that the REMOTE_ADDR will be completely empty if you bind Gunicorn to a UNIX socket and not a TCP host:port tuple.
To serve an app from a Virtualenv it is generally easiest to just install Gunicorn directly into the Virtualenv. This will create a set of Gunicorn scripts for that Virtualenv which can be used to run applications normally.
If you have Virtualenv installed, you should be able to do something like this:
$ mkdir ~/venvs/
$ virtualenv ~/venvs/webapp
$ source ~/venvs/webapp/bin/activate
$ pip install gunicorn
$ deactivateThen you just need to use one of the three Gunicorn scripts that was installed into ~/venvs/webapp/bin.
Note: You can force the installation of Gunicorn in your Virtualenv by passing -I or --ignore-installed option to pip:
$ source ~/venvs/webapp/bin/activate
$ pip install -I gunicornNote
Make sure that when using either of these service monitors you do not enable the Gunicorn's daemon mode. These monitors expect that the process they launch will be the process they need to monitor. Daemonizing will fork-exec which creates an unmonitored process and generally just confuses the monitor services.
Gaffer can be used to monitor Gunicorn. A simple configuration is:
[process:gunicorn]
cmd = gunicorn -w 3 test:app
cwd = /path/to/projectThen you can easily manage Gunicorn using Gaffer.
Create a Procfile in your project:
gunicorn = gunicorn -w 3 test:appYou can launch any other applications that should be launched at the same time.
Then you can start your Gunicorn application using Gaffer.:
gaffer startIf gafferd is launched you can also load your Procfile in it directly:
gaffer loadAll your applications will be then supervised by gafferd.
A popular method for deploying Gunicorn is to have it monitored by runit. Here is an example service definition:
#!/bin/sh
GUNICORN=/usr/local/bin/gunicorn
ROOT=/path/to/project
PID=/var/run/gunicorn.pid
APP=main:application
if [ -f $PID ]; then rm $PID; fi
cd $ROOT
exec $GUNICORN -c $ROOT/gunicorn.conf.py --pid=$PID $APPSave this as /etc/sv/[app_name]/run, and make it executable (chmod u+x /etc/sv/[app_name]/run). Then run ln -s /etc/sv/[app_name] /etc/service/[app_name]. If runit is installed, Gunicorn should start running automatically as soon as you create the symlink.
If it doesn't start automatically, run the script directly to troubleshoot.
Another useful tool to monitor and control Gunicorn is Supervisor. A simple configuration is:
[program:gunicorn]
command=/path/to/gunicorn main:application -c /path/to/gunicorn.conf.py
directory=/path/to/project
user=nobody
autostart=true
autorestart=true
redirect_stderr=trueUsing Gunicorn with upstart is simple. In this example we will run the app "myapp" from a virtualenv. All errors will go to /var/log/upstart/myapp.log.
/etc/init/myapp.conf:
description "myapp"
start on (filesystem)
stop on runlevel [016]
respawn
setuid nobody
setgid nogroup
chdir /path/to/app/directory
exec /path/to/virtualenv/bin/gunicorn myapp:appA tool that is starting to be common on linux systems is Systemd. Here are configurations files to set the Gunicorn launch in systemd and the interfaces on which Gunicorn will listen. The sockets will be managed by systemd:
gunicorn.service:
[Unit]
Description=gunicorn daemon
Requires=gunicorn.socket
After=network.target
[Service]
PIDFile=/run/gunicorn/pid
User=someuser
Group=someuser
WorkingDirectory=/home/someuser
ExecStart=/home/someuser/gunicorn/bin/gunicorn --pid /run/gunicorn/pid test:app
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID
PrivateTmp=true
[Install]
WantedBy=multi-user.targetgunicorn.socket:
[Unit]
Description=gunicorn socket
[Socket]
ListenStream=/run/gunicorn/socket
ListenStream=0.0.0.0:9000
ListenStream=[::]:8000
[Install]
WantedBy=sockets.targettmpfiles.d/gunicorn.conf:
d /run/gunicorn 0755 someuser someuser -After running curl http://localhost:9000/, Gunicorn should start and you should see something like that in logs:
2013-02-19 23:48:19 [31436] [DEBUG] Socket activation sockets: unix:/run/gunicorn/socket,http://0.0.0.0:9000,http://[::]:8000Logging can be configured by using various flags detailed in the configuration documentation or by creating a logging configuration file. Send the USR1 signal to rotate logs if you are using the logrotate utility:
kill -USR1 $(cat /var/run/gunicorn.pid)