从 launchd 启动的 Python 脚本给出 ImportError: No module named foo

Question

When the python script iftttbot.py is run with launchd using iftttbot.plist (both included below) it gives the error:

Traceback (most recent call last):
  File "/usr/bin/iftttbot.py", line 1, in <module>
    from selenium import webdriver
ImportError: No module named selenium

Terminal also gives that error, but only if I explicitly use the full path of the python binary. Omitting the full path when calling the python binary results in the script running as expected.

iftttbot.plist sets the PATH variable to the the same as what my bash PATH variable is. Setting the PYTHONPATH variable to equal this too does not affect the behaviour.

What is the proper way to run python scripts from launchd so that the modules are found?

iftttbot.plist - installed as a user agent

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Disabled</key>
    <false/>
    <key>EnvironmentVariables</key>
    <dict>
        <key>HOME</key>
        <string>/users/scottmeup</string>
        <key>PATH</key>
        <string>/Users/scottmeup/.local/bin:/opt/local/bin:/opt/local/sbin:/Users/scottmeup/.nvm/versions/node/v15.8.0/bin:/Users/scottmeup/opt/anaconda3/bin:/Users/scottmeup/opt/anaconda3/condabin:/Library/Frameworks/Python.framework/Versions/3.8/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin</string>
        <!--
        <key>PYTHONPATH</key>
        <string>/Users/scottmeup/.local/bin:/opt/local/bin:/opt/local/sbin:/Users/scottmeup/.nvm/versions/node/v15.8.0/bin:/Users/scottmeup/opt/anaconda3/bin:/Users/scottmeup/opt/anaconda3/condabin:/Library/Frameworks/Python.framework/Versions/3.8/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin</string>
        -->
    </dict>
    <key>Label</key>
    <string>com.scottmeup.iftttbot</string>
    <key>ProgramArguments</key>
    <array>
        <string>/opt/local/bin/bash</string>
        <string>-c</string>
        <string>exec python /usr/bin/iftttbot.py username password AppletID</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>StandardErrorPath</key>
    <string>/tmp/ifttt_err.log</string>
    <key>StandardOutPath</key>
    <string>/tmp/ifttt.log</string>
    <key>StartInterval</key>
    <integer>60</integer>
</dict>
</plist>

iftttbot.py

#!/opt/local/bin/python
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from time import sleep
import requests, threading,glob,sys
import bs4 as bs
from selenium.webdriver.common.action_chains import ActionChains
...
print("Invalid input, usage requires: Username Password AppletID")
...

removing #!/opt/local/bin/python does not prevent the error

Some terminal testing showed that the module isn't found when the full path to the python binary is used, otherwise the script runs as expected:

$ which python
/opt/local/bin/python

$ /opt/local/bin/python iftttbot.py
Traceback (most recent call last):
  File "iftttbot.py", line 1, in <module>
    from selenium import webdriver
ImportError: No module named selenium

$ python iftttbot.py
Invalid input, usage requires: Username Password AppletID

$ echo $PATH
/Users/scottmeup/.local/bin:/opt/local/bin:/opt/local/sbin:/Users/scottmeup/.nvm/versions/node/v15.8.0/bin:/Users/scottmeup/opt/anaconda3/bin:/Users/scottmeup/opt/anaconda3/condabin:/Library/Frameworks/Python.framework/Versions/3.8/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin

Python 3.7.10

macOS 10.13.6

Answer 1

Changing the following line resolved the issue:

    <string>exec python /usr/bin/iftttbot.py username password AppletID</string>

---

    <string>exec python3 /usr/bin/iftttbot.py username password AppletID</string>