Manage headless displays with Xvfb (X virtual framebuffer)
Project description
Manage headless displays with Xvfb (X virtual framebuffer)
Info:
Development: https://github.com/cgoldberg/xvfbwrapper
Releases: https://pypi.org/project/xvfbwrapper
Author: Corey Goldberg - 2012-2025
License: MIT
About xvfbwrapper:
xvfbwrapper is a python module for controlling virtual displays with Xvfb.
What is Xvfb?:
Xvfb (X virtual framebuffer) is a display server implementing the X11 display server protocol. It runs in memory and does not require a physical display or input devices. Only a network layer is necessary.
Xvfb is useful for running acceptance tests on headless servers.
Install xvfbwrapper from PyPI:
pip install xvfbwrapper
System Requirements:
Python 3.8+
X Window System
Xvfb (sudo apt-get install xvfb, yum install xorg-x11-server-Xvfb, etc)
File locking with fcntl
Examples:
Basic Usage:
from xvfbwrapper import Xvfb
vdisplay = Xvfb()
vdisplay.start()
try:
# launch stuff inside virtual display here.
finally:
# always either wrap your usage of Xvfb() with try / finally,
# or alternatively use Xvfb as a context manager.
# If you don't, you'll probably end up with a bunch of junk in /tmp
vdisplay.stop()
Basic Usage, specifying display geometry:
from xvfbwrapper import Xvfb
vdisplay = Xvfb(width=1280, height=740)
vdisplay.start()
try:
# launch stuff inside virtual display here.
finally:
vdisplay.stop()
Basic Usage, specifying display number:
from xvfbwrapper import Xvfb
vdisplay = Xvfb(display=23)
vdisplay.start()
# Xvfb is started with display :23
# see vdisplay.new_display
Usage as a Context Manager:
from xvfbwrapper import Xvfb
with Xvfb() as xvfb:
# launch stuff inside virtual display here.
# Xvfb will stop when this block completes
Usage in Testing: Headless Selenium WebDriver Tests:
This test class uses selenium webdriver and xvfbwrapper to run tests on Chrome with a headless display.
import unittest
from selenium import webdriver
from xvfbwrapper import Xvfb
class TestPages(unittest.TestCase):
def setUp(self):
self.xvfb = Xvfb(width=1280, height=720)
self.addCleanup(self.xvfb.stop)
self.xvfb.start()
self.browser = webdriver.Chrome()
self.addCleanup(self.browser.quit)
def testUbuntuHomepage(self):
self.browser.get('https://www.ubuntu.com')
self.assertIn('Ubuntu', self.browser.title)
def testGoogleHomepage(self):
self.browser.get('https://www.google.com')
self.assertIn('Google', self.browser.title)
if __name__ == '__main__':
unittest.main()
virtual display is launched
Chrome launches inside virtual display (headless)
browser is not shown while tests are run
conditions are asserted in each test case
browser quits during cleanup
virtual display stops during cleanup
Look Ma’, no browser!
(You can also take screenshots inside the virtual display to help diagnose test failures)
Usage with multi-threaded execution
To run several xvfb servers at the same time, you can use the environ keyword when starting the Xvfb instances. This provides isolation between threads. Be sure to use the environment dictionary you initialize Xvfb with in your subsequent system calls. Also, if you wish to inherit your current environment you must use the copy method of os.environ and not simply assign a new variable to os.environ:
from xvfbwrapper import Xvfb
import subprocess as sp
import os
isolated_environment = os.environ.copy()
xvfb = Xvfb(environ=isolated_environment)
xvfb.start()
sp.run(
"xterm & sleep 1; kill %1 ",
shell=True,
env=isolated_environment,
)
xvfb.stop()
xvfbwrapper Development: running the unit tests:
To create a virtual env and install required testing libraries:
$ python -m venv venv
$ source ./venv/bin/activate
(venv)$ pip install -r requirements_test.txt
To run all tests, linting, and type checking across all supported/installed Python environments:
(venv)$ tox
To run all tests in the default Python environment:
(venv)$ pytest