7 easy steps to automated git push deployments. With small and configurable bash only post-receive hook

Git push deployment in 7 easy steps.md

How-to setup a simple git push deployment

On the server (example.com)

1. Create a user on example.com, as which we (the git client) connect (push) to exmaple.com. We set git-shell as the login shell, so it is not possible to interactively login as this user.

sudo useradd -m -s /usr/bin/git-shell git

2. Add your ssh public key to the authorized_keys file of the created user:

## Because user git can not interactively login, we have to use sudo to get git temporarily
sudo -u git bash
cd ~
mkdir -p .ssh
vim .ssh/authorized_keys
## Paste your public key and save

3. Create a git bare repo for your project:

mkdir testapp
cd testapp
## /home/git/testapp
git init --bare

4. Copy the post-receive script from this gist to the hooks dir of the created bare repo.

vim hooks/post-receive
## Paste the post-receive script from this gist and save
## If you do not need to execute a 'build' and/or 'restart' command,
## just delete or comment the lines 'UPDATE_CMD' and 'RESTART_CMD'
chmod +x hooks/post-receive

5. Create a folder inside the /var/www that will be our DEPLOY_ROOT and set permissions to git:git :

#  sudo mkdir /disk03/physycom/coulomb11
sudo mkdir /path/to/deployed/website/folder
#  sudo chown git.git /disk03/physycom/coulomb11
sudo chown git.git /path/to/deployed/website/folder

On the client

6. Create a git repo and add our newly created remote:

mkdir testapp
cd testapp
git init
git remote add production git@example.com:~/testapp

7. Copy some files, commit and push to production:

$ git add .
$ git commit -m "deploy"
$ git push production master
Counting objects: 12, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 432 bytes | 0 bytes/s, done.
Total 4 (delta 2), reused 0 (delta 0)
remote: +++++++++++++++++++++++ Welcome to 'example.com' (1.2.3.4) ++++++++++++++++++++++++
remote: 
remote: githook: I will deploy 'master' branch of the 'testapp' project to '/var/www/testapp'
remote: 
remote: githook: UPDATE (CMD: 'cd "${DEPLOY_TO}" && make "update"'):
remote: Makefile: Doing UPDATE stuff like grunt, gulp, rake,...
remote: git
remote: /var/www/testapp
remote: 
remote: ++++++++++++++++++++ See you soon at 'example.com' (1.2.3.4) ++++++++++++++++++++++
To git@example.com:~/testapp
   08babc4..95cabcc  master -> master

post-receive

#!/bin/bash
#
# Author: "FRITZ Thomas" <fritztho@gmail.com> (http://www.fritzthomas.com)
# GitHub: https://gist.github.com/thomasfr/9691385
#
# The MIT License (MIT)
#
# Copyright (c) 2014-2017 FRITZ Thomas
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#


# Application Name:
export DEPLOY_APP_NAME=`whoami`

# This is the root deploy dir.
#export DEPLOY_ROOT="/disk03/physycom/coulomb11"
export DEPLOY_ROOT="/path/to/deployed/website/folder"

# When receiving a new git push, the received branch gets compared to this one.
# If you do not need this, just add a comment
export DEPLOY_ALLOWED_BRANCH="master"

# You could use this to do a backup before updating to be able to do a quick rollback. 
# If you need this just delete the comment and modify to your needs
#PRE_UPDATE_CMD='cd ${DEPLOY_ROOT} && backup.sh'

# Use this to do update tasks and maybe service restarts
# If you need this just delete the comment and modify to your needs
#POST_UPDATE_CMD='cd ${DEPLOY_ROOT} && make update'

###########################################################################################

export GIT_DIR="$(cd $(dirname $(dirname $0));pwd)"
export GIT_WORK_TREE="${DEPLOY_ROOT}"

echo "githook: $(date): Welcome to '$(hostname -f)'"
echo

# Loop, because it is possible to push more than one branch at a time. (git push --all)
while read oldrev newrev refname
do

    export DEPLOY_BRANCH=$(git rev-parse --symbolic --abbrev-ref $refname)
    export DEPLOY_OLDREV="$oldrev"
    export DEPLOY_NEWREV="$newrev"
    export DEPLOY_REFNAME="$refname"

    if [ "$DEPLOY_NEWREV" = "0000000000000000000000000000000000000000" ]; then
        echo "githook: This ref has been deleted"
        exit 1
    fi    

    if [ ! -z "${DEPLOY_ALLOWED_BRANCH}" ]; then
        if [ "${DEPLOY_ALLOWED_BRANCH}" != "$DEPLOY_BRANCH" ]; then
            echo "githook: Branch '$DEPLOY_BRANCH' of '${DEPLOY_APP_NAME}' application will not be deployed. Exiting."
            exit 1
        fi
    fi

    if [ ! -z "${PRE_UPDATE_CMD}" ]; then
       echo
       echo "githook: PRE UPDATE (CMD: '${PRE_UPDATE_CMD}'):"
       eval $PRE_UPDATE_CMD || exit 1
    fi

    # Make sure GIT_DIR and GIT_WORK_TREE is correctly set and 'export'ed. Otherwhise
    # these two environment variables could also be passed as parameters to the git cli
    echo "githook: I will deploy '${DEPLOY_BRANCH}' branch of the '${DEPLOY_APP_NAME}' project to '${DEPLOY_ROOT}'"
    git checkout -f "${DEPLOY_BRANCH}" || exit 1
    git reset --hard "$DEPLOY_NEWREV" || exit 1

    if [ ! -z "${POST_UPDATE_CMD}" ]; then
       echo
       echo "githook: POST UPDATE (CMD: '${POST_UPDATE_CMD}'):"
       eval $POST_UPDATE_CMD || exit 1
    fi

done

echo
echo "githook: $(date): See you soon at '$(hostname -f)'"
exit 0