问题
I have read most of the python/cron here in stackoverflow and yet couldn't make my script run. I understood that I need to run my script through shell (using zsh & ipython by the way), but really I have no idea what to do :/
My simple code:
In the crontab-
*/1 * * * * ipython /home/usr/Data/progs/cron_test.py
My python script-
import pickle
from selenium import webdriver
driver = webdriver.Firefox()
driver.get('http://www.google.com')
t=driver.current_url
pickle.dump(t,open('noreal','wb'))
I have tried some things already but to no avail:
#!python ../python etc
SHELL = /usr/bin/zsh
PATH =/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
Simply because I don't know what the problem is, I assume something with running python script via interpreter, but I don't know what I am doing really :)
A working solution would be great, and I would really appreciate an explanation to accompany any solution so I could understand the why and how and not just be like 'It works! Thanks! Bye!'
Thanks for any help!
Update So far I have narrowed down the problem, and now python runs with the following settings:
*/3 * * * * /usr/local/bin/ipython /home/user/Data/progs/RF/cron_test.py
and I got a traceback:
[1;31m---------------------------------------------------------------------------[0m
[1;31mWebDriverException[0m Traceback (most recent call last)
[1;32m/usr/local/lib/python2.7/dist-packages/IPython/utils/py3compat.pyc[0m in [0;36mexecfile[1;34m(fname, *where)[0m
[0;32m 176[0m [1;32melse[0m[1;33m:[0m[1;33m[0m[0m
[0;32m 177[0m [0mfilename[0m [1;33m=[0m [0mfname[0m[1;33m[0m[0m
[1;32m--> 178[1;33m [0m__builtin__[0m[1;33m.[0m[0mexecfile[0m[1;33m([0m[0mfilename[0m[1;33m,[0m [1;33m*[0m[0mwhere[0m[1;33m)[0m[1;33m[0m[0m
[0m
[1;32m/home/user/Data/progs/FB/cron_test.py[0m in [0;36m<module>[1;34m()[0m
[0;32m 9[0m [1;33m[0m[0m
[0;32m 10[0m [1;33m[0m[0m
[1;32m---> 11[1;33m [0mdriver[0m [1;33m=[0m [0mwebdriver[0m[1;33m.[0m[0mFirefox[0m[1;33m([0m[1;33m)[0m[1;33m[0m[0m
[0m[0;32m 12[0m [0mdriver[0m[1;33m.[0m[0mget[0m[1;33m([0m[1;34m'http://www.google.com'[0m[1;33m)[0m[1;33m[0m[0m
[0;32m 13[0m [1;33m[0m[0m
[1;32m/usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/webdriver.pyc[0m in [0;36m__init__[1;34m(self, firefox_profile, firefox_binary, timeout, capabilities, proxy)[0m
[0;32m 58[0m RemoteWebDriver.__init__(self,
[0;32m 59[0m command_executor=ExtensionConnection("127.0.0.1", self.profile,
[1;32m---> 60[1;33m self.binary, timeout),
[0m[0;32m 61[0m desired_capabilities=capabilities)
[0;32m 62[0m [0mself[0m[1;33m.[0m[0m_is_remote[0m [1;33m=[0m [0mFalse[0m[1;33m[0m[0m
[1;32m/usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/extension_connection.pyc[0m in [0;36m__init__[1;34m(self, host, firefox_profile, firefox_binary, timeout)[0m
[0;32m 45[0m [0mself[0m[1;33m.[0m[0mprofile[0m[1;33m.[0m[0madd_extension[0m[1;33m([0m[1;33m)[0m[1;33m[0m[0m
[0;32m 46[0m [1;33m[0m[0m
[1;32m---> 47[1;33m [0mself[0m[1;33m.[0m[0mbinary[0m[1;33m.[0m[0mlaunch_browser[0m[1;33m([0m[0mself[0m[1;33m.[0m[0mprofile[0m[1;33m)[0m[1;33m[0m[0m
[0m[0;32m 48[0m [0m_URL[0m [1;33m=[0m [1;34m"http://%s:%d/hub"[0m [1;33m%[0m [1;33m([0m[0mHOST[0m[1;33m,[0m [0mPORT[0m[1;33m)[0m[1;33m[0m[0m
[0;32m 49[0m RemoteConnection.__init__(
[1;32m/usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/firefox_binary.pyc[0m in [0;36mlaunch_browser[1;34m(self, profile)[0m
[0;32m 59[0m [1;33m[0m[0m
[0;32m 60[0m [0mself[0m[1;33m.[0m[0m_start_from_profile_path[0m[1;33m([0m[0mself[0m[1;33m.[0m[0mprofile[0m[1;33m.[0m[0mpath[0m[1;33m)[0m[1;33m[0m[0m
[1;32m---> 61[1;33m [0mself[0m[1;33m.[0m[0m_wait_until_connectable[0m[1;33m([0m[1;33m)[0m[1;33m[0m[0m
[0m[0;32m 62[0m [1;33m[0m[0m
[0;32m 63[0m [1;32mdef[0m [0mkill[0m[1;33m([0m[0mself[0m[1;33m)[0m[1;33m:[0m[1;33m[0m[0m
[1;32m/usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/firefox_binary.pyc[0m in [0;36m_wait_until_connectable[1;34m(self)[0m
[0;32m 98[0m raise WebDriverException("The browser appears to have exited "
[0;32m 99[0m [1;34m"before we could connect. The output was: %s"[0m [1;33m%[0m[1;33m[0m[0m
[1;32m--> 100[1;33m self._get_firefox_output())
[0m[0;32m 101[0m [1;32mif[0m [0mcount[0m [1;33m==[0m [1;36m30[0m[1;33m:[0m[1;33m[0m[0m
[0;32m 102[0m [0mself[0m[1;33m.[0m[0mkill[0m[1;33m([0m[1;33m)[0m[1;33m[0m[0m
[1;31mWebDriverException[0m: Message: 'The browser appears to have exited before we could connect. The output was: Error: no display specified\n'
回答1:
A quick guess, your job fails to run because it requires an X session. You should setup your test script to run in a headless mode. Check this link to run selenium in a headless mode.
update:
Your trace says exactly what I meant, firefox does not run without X, or a display if you want.
The output was: Error: no display specified\n'
Save yourself more trouble, read the link I posted.
回答2:
As seen here, you need to give cron a display:
30 5 * * * export DISPLAY=:0; /home/me/good_morning.sh
回答3:
You can do it without crontab.
I found schedule modul: GIThub/schedule
Now your code should look like:
import schedule
import time
def job():
import pickle
from selenium import webdriver
driver = webdriver.Firefox()
driver.get('http://www.google.com')
t=driver.current_url
pickle.dump(t,open('noreal','wb'))
schedule.every(1).minutes.do(job)
while True:
schedule.run_pending()
time.sleep(1)
It is not best solution but it works.
回答4:
Install Xvfb or Xephyr or Xvnc. Also install pyvirtualdisplay python module. This is for Ubuntu 14.04 and tested on 16.04 as well.
sudo apt-get install python-pip
sudo apt-get install xvfb xserver-xephyr vnc4server
sudo pip install pyvirtualdisplay
# optional
sudo apt-get install python-pil scrot
sudo pip install pyscreenshot
Now you can start Xvfb from your python script. It will start Xvfb when your script will be executed. Add the following lines to your code.
from pyvirtualdisplay import Display
display = Display(visible=0, size=(1024, 768))
display.start()
Here is the example code.
from pyvirtualdisplay import Display
from selenium import webdriver
display = Display(visible=0, size=(1024, 768))
display.start()
browser = webdriver.Firefox()
browser.get('http://www.google.com')
print browser.title
browser.quit()
display.stop()
Now you can mention the program in your crontab. But add the path of ipython instead of ipython only.
0 * * * * /usr/bin/python /home/usr/Data/progs/cron_test.py build
来源：https://stackoverflow.com/questions/20575751/execute-python-selenium-script-in-crontab