git precommit hook checking for JIRA in commit message.

prepare-commit-msg

#!/bin/bash

# Place in project's .git/hooks directory. File must be called "prepare-commit-msg".
# i.e. <project root>/.git/hooks/prepare-commit-msg
FILE=$1
MESSAGE=$(cat $FILE)

current_branch="$(git rev-parse --abbrev-ref HEAD)"

jira_regex='^[[:upper:]]{2,}-[[:digit:]]+[[:space:]]'
merge_regex='^Merge branch'
no_jira_error_msg="Aborting commit. Your commit message needs to start with a JIRA-1234 followed by a space."

jira_from_branch=$(echo $current_branch | grep -Eo '^(\w+/)?(\w+[-_])?[0-9]+' | grep -Eo '(\w+[-])?[0-9]+' | tr "[:lower:]" "[:upper:]")

# If there is already a JIRA at the beginning of the commit message
# continue with commit action.
if [[ $MESSAGE =~ $jira_regex || "$MESSAGE" == "${jira_from_branch} *" || $MESSAGE =~ $merge_regex ]]; then
    exit 0;
fi

# If we successfully pulled something from the branch name, lets
# assume it is a JIRA and prepend it to the commit message then proceed
# with the commit action.
if [[ -n "${jira_from_branch}" ]]; then
    echo "$jira_from_branch $MESSAGE" > $FILE
    exit 0;
fi

# If we cannot detect a JIRA in the commit message, abort commit.
if ! grep -iqE "$jira_regex" "$FILE"; then
    echo "$no_jira_error_msg" >&2
    exit 1
fi