I am trying to test a simple cronjob and when I check if the cronjob has executed, it shows that it has but no file is being created as part of the task.
I have the following script, testjob.py which needs to be executed:
#!/usr/bin/env python3
import datetime
with open('testcron.txt', 'a') as outfile:
outfile.write('\n' + str(datetime.datetime.now() + 'myname'))
This is the cronjob:
#!/usr/bin/env python3
from crontab import CronTab
my_cron = CronTab(user='myname')
job = my_cron.new(command = 'python /Users/myname/Desktop/customers/cronjob/testjob.py')
#schedule job to run every 2 minutes
job.minute.every(1)
my_cron.write()
How can I troubleshoot this?
link to image with my crontab running via crontab -e: https://i.stack.imgur.com/pj9Pt.png
You can set up a cron job via crontab -e, which is much better than creating a python script to create a cron job. But anyways.
You can first troubleshoot by actually running your python script and seeing if there are any errors, and if the file is even created.
make sure the user for that cron job has the right permissions to execute the script.
try executing the command: python /Users/myname/Desktop/customers/cronjob/testjob.py directly from your terminal.
Judging from your response, the reason why its not working is because your script isn't able to open the text file.
When you're executing the script via: python /Users/myname/Desktop/customers/cronjob/testjob.py, the location of your text file "testcron.txt" depends entirely on where you are executing the script from.
So basically, unless "testcron.txt" is located in the same path / directory from where you are executing the script, its not going to work.
You can fix this by changing your cron tab to first navigate to where your text file is, and then run the python script.
For example, if your "testcron.txt" file is located in /Users/myname/Desktop/customers/cronjob/ then write your cron job as:
cd /Users/myname/Desktop/customers/cronjob && python ./testjob.py
You can instead of running the cron job with the python command run it like a shell script.
testjob.py:
#!/usr/bin/env python3
import datetime
with open('testcron.txt', 'a') as outfile:
outfile.write('\n' + str(datetime.datetime.now() + 'myname'))
Cronjob:
#!/usr/bin/env python3
from crontab import CronTab
my_cron = CronTab(user='myname')
job = my_cron.new(command = '/Users/myname/Desktop/customers/cronjob/testjob.py')
#schedule job to run every 2 minutes
job.minute.every(1)
my_cron.write()
Make sure you run chmod a+x /Users/myname/Desktop/customers/cronjob/testjob.py first to make the python executable.
I have a script that runs perfectly from command line:
/home/anaconda2/bin/python /project_folder/script.py
I added some details below:
$ echo $PYTHONPATH
:/project_folder/
$ which python
/home/anaconda2/bin/python
Which runs the script perfectly, flawlessly.
Then from within crontab (which has been successful for another script that didn't have local import issues) I can't get the script to run.
Crontab of code that doesn't work:
PYTHONPATH=/project_folder
* * * * * /home/anaconda2/bin/python /project_folder/script.py
Nothing happens. It's killing me and much of my time trying to figure this one out - any help much appreciated.
I resolved it via creating a wrapper shell script. Ugly in that i'm exporting the python path each time, but it works.
#!/bin/bash
export PYTHONPATH="${PYTHONPATH}:/project_folder"
source ~/.bash_profile
cd /project_folder && /my/anaconda/location/bin/python /project_folder/cript.py
crontab fails to execute a Python script. The command line I am using to run the Python script is ok.
These are solutions I had tried:
add #!/usr/bin/env python at the top of the main.py
add PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin at the top of crontab
chmod 777 to the main.py file
service cron restart
my crontab is:
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
*/1 * * * * python /home/python_prj/main.py
and the log in /var/log/syslog is:
Nov 6 07:08:01 localhost CRON[28146]: (root) CMD (python /home/python_prj/main.py)
and nothing else.
The main.py script calls some methods from other modules under python_prj, does that matter?
Anyone can help me?
The main.py script calls some methods from other modules under python_prj, does that matter?
Yes, it does. All modules need to be findable at run time. You can accomplish this in several ways, but the most appropriate might be to set the PYTHONPATH variable in your crontab.
You might also want to set the MAILTO variable in crontab so you get emails with any tracebacks.
[update] here is the top of my crontab:
www:~# crontab -l
DJANGO_SETTINGS_MODULE=djangocron.settings
PATH=...
PYTHONPATH=/home/django
MAILTO="cron-notices#example.com"
...
# m h dom mon dow command
10-50/10 * * * * /home/django/cleanup_actions.py
...
(running cleanup actions every 10 minutes, except at the top of the hour).
Any file access in your scripts? And if so, have you used relative paths (or even: no explicit path) in your script?
When run from commandline, the actual folder is 'your path', where you start the script from. When run by cron, 'your path' may be different depending on environment variables.
So try using absolute paths to any files you access.
Check the permissions of the script. Make sure that it's executable by cron-- try chmod +x main.py.
This question already has answers here:
CronJob not running
(19 answers)
Closed 2 years ago.
My python script is not running under my crontab.
I have placed this in the python script at the top:
#!/usr/bin/python
I have tried doing this:
chmod a+x myscript.py
Added to my crontab -e:
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=""
* * * * * /home/me/project/myscript.py
My /var/log/cron file says:
Sep 21 11:53:02 163-dhcp /USR/SBIN/CROND[2489]: (me) CMD (/home/me/project/myscript.py)
But my script is not running because when I check my sql database, nothing has changed. If I run it directly in the terminal like so:
python /home/me/project/myscript.py
I get the correct result.
This is the myscript.py:
#!/usr/bin/python
import sqlite3
def main():
con = sqlite3.connect("test.db")
with con:
cur = con.cursor()
cur.execute("CREATE TABLE IF NOT EXISTS testtable(Id INTEGER PRIMARY KEY, Name TEXT)")
cur.execute("INSERT INTO testtable(Name) VALUES ('BoB')")
cur.execute("SELECT * FROM testtable")
print cur.fetchall()
if __name__ == "__main__":
main()
Per comments: Yes, /usr/bin/python exists. I can also run the python script directly using just /home/me/project/myscript.py. /usr/bin/python /home/me/project/myscript.py works. So I don't believe this is the cause?
There are a lot of half answers across the internet so I thought I would capture this to save someone else some time.
First, cronjob does a poor job of telling you where this is failing. I recommend sending stderr output to a log file like this:
Crontab Command:
# m h dom mon dow command
* * * * * /path/to/your_file.sh >> out.txt 2>&1
As this is likely running the command as user, check home directory for the log file. Note this script runs every minute which is good for debugging.
The next issue is you probably have a path problem... as script likely is trying to execute from your home directory. This script sets the current directory, echos it to file, and then runs your program.
Try this :
Script File
#!/bin/sh
cd "$(dirname "$0")";
CWD="$(pwd)"
echo $CWD
python your_python_file.py
Hope this saves someone else some debugging time!!!
What happens when you type
/home/me/project/myscript.py into the shell?
Can you explicitly use /usr/bin/python in your crontbb command?
Can you either use an absolute path to your test.db or cd to the correct directory then execute your python script?
This is helpful to have debug statements in your python and log some data. Crontab can be very tricky to debug.
It is possible that the script does not start because it cannot locate the python interpreter. Crontab environment may be very different from the shell environment which you are using. The search paths may be differ significantly.
Also, you test your script by starting the python interpreter explicitly while you expect the crontab to only start the script.
I put this line at the top of my python scripts:
\#!/bin/env python
This line will help locate the interpreter regardless of which directory it is installed in as long as it is in the search path.
It's usually because the python used by crontab is different from the one you use in the shell.
The easiest way to solve this is:
get the python you use in the shell:
$ which python # it may be "python3" or something else
/usr/bin/python
use that specific python in crontab file:
* * * * * /usr/bin/python test.py
Also want to mention that using env -i /bin/bash --noprofile --norc in the shell lets you have the same environment as the one used by crontab, and this is super helpful to debug.
Typically, crontab problems like this are caused by the PATH environment variable being more restrictive/different than what your normal user's PATH environment is. Since your shell uses the PATH environment to find the executable (e.g. /usr/bin/python is found in /usr/bin when you type "python" at a shell prompt), when the PATH is missing common locations, like /usr/bin or /usr/sbin, your cron job will fail. This has bit me many times. The simple fix is just to explicitly set the PATH yourself near the top of your crontab file, before any commands that need it. So, just edit the crontab as usual and add something like this near the top (if your binary is not in one of the below paths, you'll need to add it after a colon):
PATH=/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin
Alternately, just use absolute paths to your binaries and scripts in crontab.
Try this
* * * * * cd <directory_where_python_file_is> && bin/app etc/app_defaults.yaml
There is some path issue with cron. So when you move to directory with python file, cron works like charm!
I'd got the same problem. Despite the fact that the script executed manually was working, in crontab no options mentioned above were working at all. I've moved my script from /home/user/script_directory/ to /opt/scripts/ and it started to work. Possible cause of the problem should be the access (read) permissions to subfolder located in home directory.
Easiest way to handle this is to add your python installation's path to PATH in top of the shell script.
Something like:
#!/usr/bin/env bash
export PATH="{path to your python installation}:$PATH"
python {python_file_name}.py
As #Shargors said you can test it by
env -i /bin/bash --noprofile --norc
If you are using anaconda for python then the path to use will be :
/home/username/anaconda3/bin/python test.py
While the answers here clearly delineate the problem and solution, I wanted to add another answer which helped me.
If your python script is calling a database, then be sure you can connect to the db properly within the cron env (to identify the cron env--> https://askubuntu.com/questions/23009/reasons-why-crontab-does-not-work). I had a file that would run from the shell, but not as a crontab unless I connected to the database as root from within the python script.
Sometimes I am facing same problem. Whatever I try something as advised here, I may not get result.
So I begin to write "trigger" bash script as follow (let's name it trigger.sh):
#!/bin/bash
/full_path/python_script.py
And I am calling trigger.sh from crontab and everything is fine.
EDIT: Of course, don't forget to do following (give execution right):
$chmod +x python_script.py
$chmod +x trigger.sh
I was working on project that includes paramiko lib, when I run the Check_.py from cmdlin it works perfect but when I set the crontab it fails with error no module name paramiko.
So to make it short:
- there were two different python versions installed 3.7 and 2.4, so I used whreris python3 to locate the python path /usr/local/bin/python3.7m so replacing the python with the path will solve the issue.
Example
* * * * * cd /home/MKhair/hlthchk/BR/ && /usr/local/bin/python3.7m /home/MKhair/hlthchk/BR/Check_.py
* * * * * cd [ path-to-the-script-dir] && [path-to-python] [path-to-the-script]
Try to put in your crontab:
* * * * * python /path/to/your/script.py
rather than
* * * * * /path/to/your/script.py
Also the shebang line is #!/usr/bin/env python in some environments. env is an executable, and you have to know where it lives with "$ which env".
Is the cron user (where the script fails) and the terminal user (when the script succeeds) are same ?
Can you redirect the job output to some file as mentioned in Cron Job Log - How to Log?. We could see whether that helps.
This might be helpful for someone. I was having this same issue (or at least a similar issue) and what helped me was to get the path in which Python (Be aware of the version you want to use python, python3, etc...) by running this:
which python3
And then, I replaced python3 for the full path of python3 in my crontab file.
what happens to my script in python that does not run through crontab every minute.
My script has execute permissions and then calls two other scripts in python.
This is the content of my crontab (#crontab -l):
*/1 * * * * /usr/bin/rsm/samplesMonitor.py
Thank you guys.
Check /var/log/syslog for errors.
DIAGNOSTICS
cron requires that each entry in a crontab end in a
newline character. If the last entry in a crontab is
missing a newline (ie, terminated by EOF), cron will
consider the crontab (at least partially) broken. A
warning will be written to syslog.
Update: According to your log message, the script is running but returning an error code. Cron will email you the output, if you have a mail agent installed.
Try either:
install a mail agent, such as: apt-get install exim4
change your cron line to log to file, like so:
* * * * * /usr/bin/rsm/samplesMonitor.py 2>&1 >> /tmp/script.log
Update 2: I re-read your question and it acurred to me that maybe you are running into python import issues. You say that your script calls two other scripts. My suggestion would be to test running your script from /. Python has a default behavior to find imports in the current working directory, so make sure your script can run from any path location.
In the crontab, you can set the starting working directory by calling your script from within another shell process. For example:
bash -c "cd THE_WORKING_DIR;/usr/bin/rsm/samplesMonitor.py"
I believe it should be */1, not *\1.
It should be */1 instead of *\1 (forward slash instead of backslash). Also, make sure the path is correct; there usually are no subdirectories under /usr/bin.
If you want it to run every minute, just do this
* * * * * /usr/bin/rsm/samplesMonitor.py