Run commands remotely through `git push` - example with 2 levels deployment

branch2command.sh

#! /usr/bin/env sh
# This script accepts 2 mandatory arguments:
# COMMAND and ENVIRONMENT
#
# It's run by git repo hook and current
# workign directory is the bare repo path
#
# Global variables accessible:
# $WORKTREE (points to the working tree)
# 
command=$1
environment=$2

if [ ! $command ] || [ ! $environment ]
then
  echo "   ___                  _ "
  echo "  / _ \  ___  _ __  ___| |"
  echo " | | | |/ _ \| '_ \/ __| |"
  echo " | |_| | (_) | |_) \__ \_|"
  echo "  \___/ \___/| .__/|___(_)"
  echo "             |_|         "
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  echo " Wrong arguments passed to branch2command.sh"
  echo "--------------------------------------------"
  echo " USAGE: branch2command.sh <command> <environment>"
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  exit 1
fi

if [ $environment == "hub" ]
then
  ###############################
  #### Match command for HUB
  ###############################
  case $command in
    # Deploy master branch to nodes
    deploy)
      script="$WORKTREE/deploy.sh"
      if [ -e $script ]
      then
        . $script master
        matched=1
      else
        echo "script could not found"
        exit 1
      fi
    ;;
    rollback)
      git --work-tree=$WORKTREE reset --hard HEAD~
      matched=1
    ;;
    # for any NODE-* commands - just redirect them to nodes..
    node-*)
      # Run this command on remote nodes
      . $WORKTREE/deploy.sh $command
    ;;
  esac
elif [ $environment == "node" ]
then
  ###############################
  #### Match command for NODE
  ###############################
  case $command in
    node-build)
      # Build script should be executed in the root
      # of working tree
      cd $WORKTREE
      script="build.sh"
      if [ -e $script ]
      then
        . $script
        matched=1
      else
        echo "script could not found"
        exit 1
      fi
    ;;
  esac
fi


######
# END
######
if [ $matched ]
then
   echo " _ .-') _                    .-') _   ('-.   "
  echo "( (  OO) )                  ( OO ) )_(  OO)  "
   echo " \     .'_  .-'),-----. ,--./ ,--,'(,------. "
   echo " ,\`'--..._)( OO'  .-.  '|   \ |  |\ |  .---' "
   echo " |  |  \  '/   |  | |  ||    \|  | )|  |     "
   echo " |  |   ' |\_) |  |\|  ||  .     |/(|  '--.  "
   echo " |  |   / :  \ |  | |  ||  |\    |  |  .--'  "
   echo " |  '--'  /   \`'  '-'  '|  | \   |  |  \`---. "
   echo " \`-------'      \`-----' \`--'  \`--'  \`------' "
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  echo "--------------------------------------------"
  echo " Command was executed. Ignore errors below"
  echo "--------------------------------------------"
  echo "---------------------------------------^----"
  echo "---------------------------------------|----"
  echo "-But verify there are no errors above--|----"
  echo "--------------------------------------------"
  exit 1
fi

pre-receive

#! /usr/bin/env sh
#
# This hook is placed in a Bare repository.
#
# It executes a script inside working tree (so it's part of repo)
# that contains some logic on "what to do" if such "branch name"
# was pushed. If it finds it, it does an action and exits
# So, we actually are using git to run commands remotely from withing
# repo hook which gives our script direct access to the repo for free
#
# Assuming following file structure:
# .
# |-- myproject
# |-- myproject.git
# set WORKTREE=../myproject
#
# Where myproject.git - current bare repo and myproject - working directory
# To enable this hook, rename this file to "pre-receive" and make sure it is executable
#
 
WORKTREE=../myproject

# environment is used in some scripts
# for instance, script "branch2command.sh" takes
# different actions depending on environment
# it runs in
#
# Possible values are: "hub", "node"
# Where "hub" is the bare repository to which
# developers push
# and "node" is for nodes that receive pushes from
# hub and that run actual apps
#
# for example, running "build" command is more reasonable
# on "node" so it will run only there
# while, running "rollback" sounds more reasonable for "hub",
# also "deploy" is good for "hub" as it is it's primary task
#
# hopefully you get the point
#

environment="hub"

while read oldrev newrev ref
do
  branch=$(echo $ref | awk -F'/' '{print $3}')

  # Convert branch name into a command
  branch2command_script="$WORKTREE/branch2command.sh"
  if [ -e "$branch2command_script" ]
  then
    . $branch2command_script $branch $environment
  fi

  if [ "$branch" != "master" ] && [ "$branch" != "docs" ]
  then
    echo Unrecognized branch name
    exit 1
  fi
done