how to deactivate virtualenv from a bash script

It'll be hard to make a service like that useful.

. ${VENV}/activate # note the dot

or

source ${VENV}/activate

will source the activate script, i.e. run its contents as if they were part of the shell or script where you source them. virtualenvironment's activate is designed for this usage. In contrast, just executing the script normally with

${VENV}/activate # note: NO dot and NO 'source' command

will run its content in a subshell and won't have any useful effect.

However, your service script will already run in a subshell of its own. So except for any python commands you run as part of the service start process, it won't have any effect.

On the plus side, you won't even have to care about de-activating the environment, unless you want to run even more python stuff in the service start process, but outside of your virtualenv.

Just deactivate. It will work in the script as well as in command line, as long as you're using bash.

Edit: also in most cases it is a better idea to spell full python path in your scripts and services. It is stateless, more portable and works pretty much everywhere. So instead of doing

. $VENV/bin/activate
/path/to/my/script.py --parameters

it is usually preferable to do

$VENV/bin/python /path/to/my/script --parameters

Trust me, it will save you debugging time)