git push docker build

#
# Simple post-receive hook that builds a docker image and pushes it somewhere.  In order for it to work
# you need to define your docker registry credentials in a .dockerrc file in your home directory:
#
# export DOCKER_USER=<user>
# export DOCKER_PASS=<password>
# export DOCKER_EMAIL=<email>
# export DOCKER_REGISTRY=<registry, e.g. tutum.co>
#

#!/bin/bash

# Source our registry credentials and login
source ~/.dockerrc
sudo docker login -u $DOCKER_USER -p $DOCKER_PASS -e $DOCKER_EMAIL $DOCKER_REGISTRY

# Setup global vars
project_name=$(basename $(pwd))
push_dest=$DOCKER_REGISTRY/$DOCKER_USER/$project_name

while read oldrev newrev refname
do
    # Setup branch-local vars
    branch=$(git rev-parse --symbolic --abbrev-ref $refname)
    tag=$push_dest:$branch
    
    # Create a temporary directory and checkout into it
    checkout=$(mktemp -d)
    GIT_WORK_TREE=$checkout git checkout -f $branch

    # Build and push
    echo "--> Building $project_name to $tag"
    
    # Wrap these commands in braces so that the cleanup
    # still happens even if the build/push fails
    {
      sudo docker build -t $tag $checkout
      sudo docker push $push_dest
    }
    
    # Cleanup after ourselves
    rm -rf $checkout
    sudo docker rmi $tag
done