The summary.
HOW TO SET IT UP
The Python application feature in cPanel creates the virtual environment and serves the application.
You provide the version, the application root, the URL, the startup file and the entry point.
THE MOST COMMON REPORT OF ALL
Changes not taking effect, because the application was not restarted.
It runs as a persistent process holding your code in memory. Restart after any code, dependency or environment change.
INSTALL DEPENDENCIES INTO THE APPLICATION'S ENVIRONMENT
Not globally. Use a requirements file with pinned versions so the environment is reproducible.
CHECK BEFORE COMMITTING TO A STACK
Whether your libraries install without system-level access. Anything needing compilation may not.
PUT CONFIGURATION IN ENVIRONMENT VARIABLES
Credentials never in code. Fail clearly at startup if a required one is missing.
FOR CRON
Use full paths to both the interpreter in your virtual environment and the script.
Cron runs with a minimal environment and inherits nothing. Test the exact command manually first.
WHEN ANYTHING FAILS
Read the application log first. It usually names the cause precisely.
WHY PYTHON APPLICATIONS HIT LIMITS
They run persistently and consume memory continuously. Anything accumulating in memory eventually exceeds the limit.
