Anyone who has built a system which captures the number of lines added/deleted for a release and per author?

So currently have developed a system using webhooks in which trigger an event when there is a merge in mainline branch. Fetch commits of the PR, store the commit metadata of those commits(Hash, lines added,lines deleted,author,JIRA from commit message, etc). Is there anyone who has built a similar system with JIRA Integration? Just wanted to know some other ideas, solutions.

One of the problems we are facing is unable to enforce jira commit message addition in Gitlab Saas, because we don't get to add pre-receive hooks. All other checks are client side which can be modified by project owners. Any inputs on same will also be appreciated.