monorepo.gitlab

Scripts helping towards Monorepo with GitLab CI.

Mostly adapted from workarounds given in gitlab-ce/issues/19232. Hopefully soon to be integrated into GitLab CI!

How to use

Add as a submodule

git submodule add https://github.com/awesome-inc/monorepo.gitlab.git .monorepo.gitlab

and update your .gitlab-ci.yml.

• Add some variables and a before_script to get the last green commit in Gitlab CI

# needs `curl`, `jq` 1.5
variables:
  GIT_SUBMODULE_STRATEGY: recursive
before_script:
    - .monorepo.gitlab/last_green_commit.sh

• Build your sub-component foo only when there are diffs in ./foo since the last green commit

build-foo:
  # before
  script: build foo
  # after
  script: .monorepo.gitlab/build_if_changed.sh foo build foo

Tips

DRY Jobs conventions/blueprints

Use YAML anchors to keep your jobs DRY.

Say your using docker-compose to orchestrate & build your services.

Your docker-compose.yml may look something like this

version: '3'
services:
  webapp:
    image: "${DOCKER_REGISTRY}/${REPO}/${PRODUCT}_webapp:${TAG}"
    build:
      context: ./webapp
  ...

And you build and push each service through a script build.sh which goes something like this

#!/bin/bash -ex
component=$1
docker-compose build ${component}
if [ "$CI_BUILD_REF_NAME" -ne "master" ]; then exit; fi
docker-compose push ${component}

This uses docker-compose to build the service specified on the command line as a tagged docker image. If you are on master it pushes the built image right away to the specified registry.

Then, your jobs in .gitlab-ci.yml could look something like this

# Use yml anchors, to keep jobs DRY, cf.: https://docs.gitlab.com/ee/ci/yaml/#anchors
.build_template: &build_definition
  tags:
    - linux
    - docker
  stage: build
  script: .monorepo.gitlab/build_if_changed.sh ${CI_JOB_NAME} ./build.sh ${CI_JOB_NAME}

webapp:
  <<: *build_definition

Docker-in-Docker executor

With awesomeinc/docker.gitlab.monorepo it is easy to use GitLab's docker-in-docker executor. Just add this to your .gitlab-ci.yml

variables:
  # cf.: https://docs.gitlab.com/ee/ci/docker/using_docker_build.html
  DOCKER_HOST: tcp://docker:2375/
  DOCKER_DRIVER: overlay2
services:
  - docker:dind
image:
  name: awesomeinc/docker.gitlab.monorepo:0.1.0
  entrypoint: [""] # force an empty entrypoint, cf.: https://gitlab.com/gitlab-org/gitlab-runner/issues/2692#workaround  

Examples

Some example usages are given in

• mkoertgen/hello.gitlab.monorepo
• mkoertgen/hello.docker-sonar
• ...