Auto pull git repositories for opengrok indexing

I've installed opengrok from a docker image on an Ubuntu server. Inside /var/opengrok/src, I cloned the desired repositories. I'd like to auto pull and auto index changes periodically. I'm not at ease with cron, is there a way to tell opengrok to pull before indexing?

• /var/opengrok/
  • docker-compose.yml
  • etc/
  • data/
  • src/
    • repo1-master/ <- need to git pull
    • repo1-dev/ <- need to git pull
    • repo2-master/ <- need to git pull
    • repo2-dev/ <- need to git pull

I finally wrote a cron task to run this script:

pull-repos.sh:

#!/bin/bash
repo_dirs=`ls -d /home/myuser/docker/opengrok/src/*`

for dir in $repo_dirs
do
        echo "Git pulling in $dir"
        cd $dir && git pull && cd ..
done

Here is the cron line:

*/15 9-18 * * mon,tue,wed,thu,fri /home/myuser/docker/opengrok/pull-repos.sh