Selenium headless does not run on CentOS 7 with Perl, "no display specified" - perl

Question

I try to run headless Selenium on CentOS7:
# cat /etc/os-release
NAME="Red Hat Enterprise Linux Server"
VERSION="7.2 (Maipo)"
I installed Xvfb and run it as
# /usr/bin/Xvfb :99
I installed firefox:
# firefox -v
Mozilla Firefox 38.5.0
and run it to check if it can be run at all:
# export DISPLAY=:99
# firefox
This is the output:
# firefox
Xlib: extension "RANDR" missing on display ":99".
console.error:
[CustomizableUI]
Custom widget with id loop-button does not return a valid node
console.error:
[CustomizableUI]
Custom widget with id loop-button does not return a valid node
GLib-GIO-Message: Using the 'memory' GSettings backend. Your settings will not be saved or shared with other applications.
Firefox seems to be running after that command:
# ps aux | grep firefox
root 29476 7.3 14.9 852356 152256 pts/3 Sl+ 10:30 0:03 /usr/lib64/firefox/firefox
EDIT
Yes, it's running. Taking screenshot from the Xvfb by
DISPLAY=:99 import -window root -crop 1264x948+0+0 /tmp/screenshot.jpg
I can see
Now the problematic part.
I installed Selenium Remote Driver for perl
# cpanm Selenium::Remote::Driver
Then I ran standalone selenium driver:
# java -jar selenium-server-standalone-2.49.0.jar
Now I run test script:
#!/usr/bin/perl
use strict;
use warnings;
use Selenium::Remote::Driver;
my $driver = Selenium::Remote::Driver->new(browser_name=>'firefox');
$driver->get('http://www.google.com');
print $driver->get_title();
$driver->quit();
After 45 second I get error from the driver:
Could not create new session: Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms. Firefox console output:
Error: no display specified
at (eval 89) line 510.
Seems like firefox launched by the driver does not see DISPLAY environment variable. I try to add it from the script:
#!/usr/bin/perl
use strict;
use warnings;
use Selenium::Remote::Driver;
$ENV{DISPLAY}=":99";
my $driver = Selenium::Remote::Driver->new(browser_name=>'firefox');
$driver->get('http://www.google.com');
print $driver->get_title();
$driver->quit();
It does not help, the previous error remains.
What do I do?
EDIT2
I tried the current setup with Python. All works.
# pip install selenium
And used the following test script:
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
driver = webdriver.Firefox()
driver.get("http://www.python.org")
f = open('ptn-sel.txt', 'w')
f.write(driver.title)
driver.close()
f.close()
I understand it's problem of Perl driver.... Any suggestions?

Answer 1

Is python using the standalone server or running firefox itself?
If perl is using the server and the server is spawning firefox then you need $DISPLAY set in the server processes environment not the script's environment. (By running export DISPLAY=:99; java -jar selenium-server-standalone-2.49.0.jaror similar.)
If you don't want to use the standalone server at all then Selenium::Firefox looks like it might be interesting.