watchtower/CONTRIBUTING.md

Prerequisites

To contribute code changes to this project you will need the following development kits.

• Go. Download and install the Go programming language
• docker

Checking out the code

When cloning watchtower to your development environment you should place your forked repo within the standard go code structure.

cd $GOPATH/src
mkdir <yourfork>
cd <yourfork>
git clone git@github.com:<yourfork>/watchtower.git
cd watchtower

Building and testing

watchtower is a go application and is built with go commands. The following commands assume that you are at the root level of your repo.

go get ./... # analyzes and retrieves package dependencies
go build     # compiles and packages an executable binary, watchtower
go test      # runs tests
./watchtower # runs the application (outside of a container)

Building the docker image

watchtower is packaged and distributed as a docker image. A golang-builder is used to package the go code and its dependencies as a minimally-sized application. The application binary is then layered into to a minimal docker image (see Dockerfile), so that the entire image is <10MB. See circle.yml for further details.The following commands assume that you are at the root level of your repo (i.e. watchtower/).

docker pull centurylink/golang-builder:latest									# download the builder
docker run -v $(pwd):/src centurylink/golang-builder:latest						# build the minimal binary
docker build -t <yourfork>/watchtower:latest .									# build the docker image
docker run -v /var/run/docker.sock:/var/run/docker.sock <yourfork>/watchtower	# run the application (inside of a container)