Development environment

1. Install dependencies and Go runtime

For Debian/Ubuntu

sudo apt-get install -y mercurial git-core wget make build-essential
wget https://storage.googleapis.com/golang/go1.13.8.linux-amd64.tar.gz
sudo tar -C /usr/local -xzf go*-*.tar.gz

For macOS

Using binary package:

wget https://storage.googleapis.com/golang/go1.13.8.darwin-amd64.tar.gz
sudo tar -C /usr/local -xzf go*-*.tar.gz

Using installation package:

wget https://storage.googleapis.com/golang/go1.13.8.darwin-amd64.pkg
open go*-*.pkg

For FreeBSD

pkg install go-1.13.8 gmake git mercurial

2. Install Docker Engine

The Docker Engine is required to create pre-built image that is embedded into runner and loaded when using Docker executor.

To install Docker, follow the Docker installation instructions for your OS.

Make sure you have a binfmt_misc on the machine that is running your Docker Engine. This is required for building ARM images that are embedded into the GitLab Runner binary.

  • For Debian/Ubuntu it’s sufficient to execute:

    sudo apt-get install binfmt-support qemu-user-static
    
  • For Docker for MacOS/Windows binfmt_misc is enabled by default.

  • For CoreOS (but also works on Debian and Ubuntu) you need to execute the following script on system start:

    #!/bin/sh
    
    set -xe
    
    /sbin/modprobe binfmt_misc
    
    mount -t binfmt_misc binfmt_misc /proc/sys/fs/binfmt_misc
    
    # Support for ARM binaries through Qemu:
    { echo ':arm:M::\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-arm-static:' > /proc/sys/fs/binfmt_misc/register; } 2>/dev/null
    { echo ':armeb:M::\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff:/usr/bin/qemu-armeb-static:' > /proc/sys/fs/binfmt_misc/register; } 2>/dev/null
    { echo ':aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/bin/qemu-aarch64-static:CF' > /proc/sys/fs/binfmt_misc/register; } 2>/dev/null
    

3. Download runner sources

go get gitlab.com/gitlab-org/gitlab-runner

4. Install runner dependencies

This will download and restore all dependencies required to build runner:

make deps

For FreeBSD use gmake deps

5. Run runner

Normally you would use gitlab-runner. In order to compile and run the Go sources, use the Go toolchain:

make build_current
./out/binaries/gitlab-runner run

You can run runner in debug-mode:

make build_current
./out/binaries/gitlab-runner --debug run

make build_current is a superset of make build_simple which in addition takes care of building Docker dependencies.

Building the Docker images

If you want to build the Docker images, run make build_current_docker, which will:

  1. Build gitlab-runner-helper and create a helper Docker image from it.
  2. Compile Runner for linux/amd64.
  3. Build a DEB package for Runner. The official Runner images are based on Alpine and Ubuntu, and the Ubuntu image build uses the DEB package.
  4. Build the Alpine and Ubuntu versions of the gitlab/gitlab-runner image.

6. Run test suite locally

GitLab Runner test suite consists of “core” tests and tests for executors. Tests for executors require certain binaries to be installed on your local machine. Some of these binaries cannot be installed on all operating systems. If a binary is not installed tests requiring this binary will be skipped.

These are the binaries that you can install:

  1. VirtualBox and Vagrant
  2. kubectl with Minikube
  3. Parallels
  4. PowerShell

After installing the binaries run:

make development_setup

To execute the tests run:

make test

8. Install optional tools

  • Install golangci-lint, used for the make lint target.
  • Install markdown-lint and vale, used for the make lint-docs target.

Installation instructions will pop up when running a Makefile target if a tool is missing.

9. Contribute

You can start hacking GitLab-Runner code. If you need an IDE to edit and debug code, there are a few free suggestions you can use:

Managing build dependencies

GitLab Runner uses Go Modules to manage its dependencies - they get checked into the repository under the vendor/ directory

Don’t add dependency from upstream master branch when version tags are available.

Developing for Windows on a non-windows environment

We provide a Vagrantfile to help you run a Windows Server 2019 or Windows 10 instance, since we are using multiple machines inside of Vagrant.

The following are required:

  • Vagrant installed.
  • Virtualbox installed.
  • Around 30GB of free hard disk space on your computer.

Which virtual machine to use depends on your use case:

  • The Windows Server machine has Docker pre-installed and should always be used when you are developing on Runner for Windows.
  • The Windows 10 machine is there for you to have a windows environment with a GUI which sometimes can help you debugging some Windows features. Note that you cannot have Docker running inside of Windows 10 because nested virtualization is not supported.

Running vagrant up windows_10 will start the Windows 10 machine for you. To:

  • SSH inside of the Windows 10 machine, run vagrant ssh windows_10.
  • Access the GUI for the Windows 10, you can connect via RDP by running vagrant rdp windows_10, which will connect to the machine using a locally installed RDP program.

For both machines, the GitLab Runner source code is synced bi-directionally so that you can edit from your machine with your favorite editor. The source code can be found under the $GOROOT environment variable. We have a RUNNER_SRC environment variable which you can use to find out the full path so when using PowerShell, you can use cd $Env:RUNNER_SRC.

Troubleshooting

docker.go missing Asset symbol

This error happens due to missing executors/docker/bindata.go file that is generated from Docker prebuilts. Which is especially tricky on Windows.

Try to execute: make deps docker, if it doesn’t help you can do that in steps:

  1. Execute go get -u github.com/jteeuwen/go-bindata/...
  2. Download https://gitlab-runner-downloads.s3.amazonaws.com/master/docker/prebuilt-x86_64.tar.xz and save to out/docker/prebuilt-x86_64.tar.xz
  3. Download https://gitlab-runner-downloads.s3.amazonaws.com/master/docker/prebuilt-arm.tar.xz and save to out/docker/prebuilt-arm.tar.xz
  4. Execute make docker or check the Makefile how this command looks like