git hook commit message for JIRA and Trello branches

git-commit-msg-jira-trello.rb

#!/usr/bin/env ruby
#
# Git commit-msg hook.
#
# If your branch name is in the form "story/DIO-1234/description",
# automatically adds "DIO-1234/description: " to commit messages, unless they mention "DIO-1234" already.
#
# If your branch name is in the form "mario/1234-my-trello-card",
# automatically adds "1234-my-trello-card: " to commit messages, unless they mention "1234" already.
#
# By Mario Izquierdo.
#
# Install:
# Create a file with this content in `yourproject/.githooks/commit-msg`
# or put this file somewhere, for example `~/.githooks/commit-msg-jira-trello`, and symlink it:
#
#     $ cd yourproject
#     $ ln -s ~/.githooks/commit-msg-jira-trello .git/hooks/commit-msg
#

branchname = `git branch --no-color 2> /dev/null`[/^\* (.+)/, 1].to_s # get current branch name
commit_message_file = ARGV[0] # argument given by git when calling this hook
original_commit_message = File.read(commit_message_file).strip

# JIRA
jira_pattern = /(DIO-\d+)\/(.*)/i # match branch names like story/DIO-1234/blabla_blabla
if m = branchname.match(jira_pattern)
  jira_number, short_desc = m.captures
  exit if original_commit_message.include?(jira_number) # do not add the jira number again if it is already in the commit message

  # Add jira_number and short_desc to commit message
  message = "#{jira_number}/#{short_desc}: #{original_commit_message}"
  File.open(commit_message_file, 'w') {|f| f.write message }
end

# Trello
trello_pattern = /\/((\d+)-[^\/]+)$/i # match branch names like mario/1234-my-trello-card
if m = branchname.match(trello_pattern)
  trello_url, trello_id = m.captures
  exit if original_commit_message.include?(trello_id) # do not add the trello url again if the id is already in the commit message

  # Add trello_url to commit message
  message = "#{trello_url}: #{original_commit_message}"
  File.open(commit_message_file, 'w') {|f| f.write message }
end