On my ubuntu server I have an application MyApp which runs as a daemon with its own user myapp.

Then I have a web application MyPortal which runs in apace httpd as user www-data. This application serves a web page with a Redeploy MyApp button. When clicking this button I want to start the script redeploymyapp. This script stops the MyApp deamon, upgrades the application and starts the daemon again.

The problem is, that the redeploymyapp script needs to be executed by the user myapp, while MyPortal is running as www-data.

What is te best way to solve this problem?