Gunicorn "green Unicorn" is a widely used high-performance Python WSGI UNIX HTTP server. It is transplanted from the Unicorn project of Ruby and uses the pre fork worker mode. It has the characteristics of very simple use, lightweight resource consumption and high performance.

Installing gunicorn

$ sudo apt-get update
$ sudo apt-get install gunicorn

Run gunicorn:

$ gunicorn [OPTIONS] Module name: variable name

The module name is the python file name, which can be the complete path + Python file name; The variable name is the callable WSGI (Web Server Gateway) in the python file

Example:

# filename: test.py
def app(environ, start_response):
"""Simplest possible application object"""
data = '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])

Run app:

$ gunicorn --workers=2 test:app

Common configuration parameters:

-c CONFIG, --config=CONFIG

Specify a configuration file (py file)

-b BIND, --bind=BIND

Bind with the specified socket

-D, --daemon

Running the Gunicorn process in the form of a daemon is actually putting the service in the background.

-w WORKERS, --workers=WORKERS

Number of work processes. As mentioned above, gunicorn is a pre fork worker mode, which means that when gunicorn is started, a specified number of worker processes will be forked in advance in the main process. When processing requests, gunicorn relies on the operating system to provide load balancing. Generally, the recommended number of workers is: (2 x $num_cores) + 1

-k WORKERCLASS, --worker-class=WORKERCLASS

Work process type. Including sync (default), eventlet, gevent, or tornado, gthread, gaiohttp

--backlog INT

Maximum number of pending connections

--chdir

Switch to the specified working directory

--log-level LEVEL

Output the granularity of error log. The effective levels are:

debug
info
warning
error
critical
--access-logfile FILE

Confirm the FILE to be written to the Access log. FILE. '-' indicates output to standard output

--error-logfile FILE, --log-file FILE

Confirm the FILE to be written to the Error log. FILE. '-' indicates output to standard error output

gunicorn configuration

Gunicorn gets the configuration from three different places:

Frame settings (usually only affect Paster applications)

Configuration file (python file): the configuration in the configuration file overrides the settings of the framework.

command line

Framework settings are only related to Paster (a Web framework) and are not discussed; The command line configuration is shown in the above section; Now let's see how to configure gunicorn with a configuration file:

The configuration file must be a python file, just write the parameters in the command line into the py file. If you need to set which parameter, you can assign a value to the parameter in the py file. For example:

# example.py
bind = "127.0.0.1:8000"
workers = 2

Run gunicorn:

$ gunicorn -c example.py test:app

Equivalent to:

$ gunicorn -w 2 -b 127.0.0.1:8000 test:app

Of course, configuration files can also achieve more complex configurations:

# gunicorn.py
import logging
import logging.handlers
from logging.handlers import WatchedFileHandler
import os
import multiprocessing
bind = '127.0.0.1:8000'   #Bind ip and port numbers
backlog = 512        #listen queue 
chdir = '/home/test/server/bin' #gunicorn the destination working directory to switch to
timeout = 30   #overtime
worker_class = 'gevent' #Using gevent mode, you can also use sync mode, which is the default
workers = multiprocessing.cpu_count() * 2 + 1  #Number of processes
threads = 2 #Specifies the number of threads open per process
loglevel = 'info' #Log level refers to the level of error log, but the level of access log cannot be set
access_log_format = '%(t)s %(p)s %(h)s "%(r)s" %(s)s %(L)s %(b)s %(f)s" "%(a)s"'  #Set the format of gunicorn access log. The error log cannot be set
"""
The meaning of each option is as follows:
h     remote address
l     '-'
u     currently '-', may be user name in future releases
t     date of the request
r     status line (e.g. ``GET / HTTP/1.1``)
s     status
b     response length or '-'
f     referer
a     user agent
T     request time in seconds
D     request time in microseconds
L     request time in decimal seconds
p     process ID
"""
accesslog = "/home/test/server/log/gunicorn_access.log"   #Access log file
errorlog = "/home/test/server/log/gunicorn_error.log"    #Error log file

Run gunicorn:

$ gunicorn -c gunicorn.py test:app

This article comes from the blog Park, author: Qiu Hua. Please indicate the link of the original text for Reprint: https://www.cnblogs.com/qiu-hua/p/12680905.html