post-receive hook for deploying a Node PM2 app to server

post-receive

#!/bin/bash
TARGET="<deployment-location>"
GIT_DIR="<repo-location>"
BRANCH="master"

while read oldrev newrev ref
do
        # only checking out the master (or whatever branch you would like to deploy)
        if [ "$ref" = "refs/heads/$BRANCH" ];
        then
                filelist=$(git diff-tree --no-commit-id --name-only -r $newrev)
                echo "Ref $ref received. Deploying ${BRANCH} branch to production..."
                git --work-tree=$TARGET --git-dir=$GIT_DIR checkout -f $BRANCH
                cd $TARGET
                # Reinstall dependencies only if there are any changes in package/package-lock files.
                if [[ $filelist == *"package.json"* || $filelist == *"package-lock.json"* ]];
                then
                        echo "Changes detected in Package files..."
                        echo "Reinstalling dependencies..."
                        npm i --only=prod
                fi
                echo "Redeploying API Server..."
                sudo pm2 restart API
        else
                echo "Ref $ref received. Doing nothing: only the ${BRANCH} branch may be deployed on this server."
        fi
done