[LINUX] How to avoid import errors when running python in Synology DSM Task Scheduler

The error that occurred

When I tried to run a Python script in Synology's DS118 from DSM's Task Scheduler, I got a module import error.

Error in the email received from DSM

Traceback (most recent call last):
  File "hoge.py", line 1, in <module>
    import tweepy
ModuleNotFoundError: No module named 'tweepy'

Isn't it funny? I can do it with an SSH connection. ..

Moreover, I had a similar error with requests before, but at that time I didn't need to do it with the task scheduler so much, so I left it. However, this time I had to do it with the task scheduler, so I decided to deal with it seriously.

When I looked it up without knowing it, it seemed that the pass did not pass. Perhaps it's subtly different from running in SSH and running in Task Scheduler.

So, I tried to deal with it as follows.

Note that python is installed from the Package Center and the version is 3.8.2, and the SDK version is DSM 6.2.3-25426 Update 3.

Check the path

From each of the SSH connection and Task Scheduler, run the following code to see if there is a difference in the list of paths.

check_module_path.py

import sys

path_list = sys.path
with open('/your_storage/your_directory/check_module_path.txt', 'w', encoding='utf-8') as f:
    for path in path_list:
        f.write(path + '\n')

When executed from an SSH connection

Path when executed from SSH connection

/my_storage/my_directory
/var/packages/py3k/target/usr/local/lib/python38.zip
/var/packages/py3k/target/usr/local/lib/python3.8
/var/packages/py3k/target/usr/local/lib/python3.8/lib-dynload
/var/services/homes/synology_user_name/.local/lib/python3.8/site-packages
/var/packages/py3k/target/usr/local/lib/python3.8/site-packages
/usr/lib/python3/site-packages

When executed from the task scheduler

Path when executed from task scheduler

/my_storage/my_directory
/var/packages/py3k/target/usr/local/lib/python38.zip
/var/packages/py3k/target/usr/local/lib/python3.8
/var/packages/py3k/target/usr/local/lib/python3.8/lib-dynload
/var/packages/py3k/target/usr/local/lib/python3.8/site-packages
/usr/lib/python3/site-packages

Hmmm, /var/services/homes/synology_user_name/.local/lib/python3.8/site-packages is in the SSH connection but not in the task scheduler. There seems to be a module for tweepy and requests here, so check the inside of this directory with ls -l from the SSH connection.

python

ls -l /var/services/homes/synology_user_name/.local/lib/python3.8/site-packages
#Abbreviation (many)
# drwxrwxrwx+  3 synology_user_name users   4096 Jan 14 05:57 tweepy
#Abbreviation (many)

There was tweepy! Of course, there was also requests!

Workaround

There are two ways to deal with it.

The first is to add about two lines of code in the script, which is easier. Of course, I'm a lazy guy who chooses the easier one if he gets lost. ..

The second method is to pass the default path from the task scheduler. Perhaps I should deal with it here, but I don't know how to do it at my level. .. But for the time being, I'll just write it.

How to deal with it in the script

Write the following code ** before the module import statement.

Described before the import statement of the module!

import sys
sys.path.append('/var/services/homes/synology_user_name/.local/lib/python3.8/site-packages')

With this alone, you can avoid errors! It's easy to understand, but it's difficult to understand, isn't it?

How to pass the default path from the task scheduler

In order to pass the path, it may be possible to add the following from ~/.bashrc with an editor such as vi, but I do not know how to do this on the task scheduler. ..

python

export PATH=$PATH:"/var/services/homes/synology_user_name/.local/lib/python3.8/site-packages"

Is it possible to do vi in the task scheduler script? ?? If you know, I would appreciate it if you could teach me m (_ _) m

reference

Check / add the path of the target directory of import in Python (sys.path etc.)| note.nkmk.me [Python environment construction] Explanation of environment variables!| WEBCAMP NAVI [Python package storage location-Qiita](https://qiita.com/ophhdn/items/4d3ecc6354d92b7ac0ba"pythonのパッケージの保存場所 - Qiita") [How to pass the default path in Python (Windows, Linux)-Qiita](https://qiita.com/maech/items/72559402556eb2af73ad"Python内のデフォルトパスを通す方法（Windows, Linux） - Qiita")