GitLab - A full DevOps tool

Sample .gitlab-ci.yml (source) :

stages:							all the stages this pipeline has, listed in execution order
  - build
  - test
  - deploy

job1:
  stage: build						which stage this job runs in
  script:
    - echo "This job compiles code."

job2:
  stage: test						which stage this job runs in
  script:
    - echo "This job tests the compiled code. It runs when the build stage completes."

job3:							when a job defines no stage, it defaults to test
  script:
    - echo "This job also runs in the test stage."

job4:
  stage: deploy						which stage this job runs in
  script:
    - echo "This job deploys the code. It runs when the test stage completes."
  environment: production

• per_page
• page

.gitlab-ci.yml

• YAML file holding GitLab CI / CD pipelines configuration

jobs

• are made of a list of commands and define what to do (compile code, run tests, )
• are written in .gitlab-ci.yml
• are executed by runners
  • jobs in the same stage can execute in parallel if they run on different runners
  • if you have only one runner, jobs can run in parallel if the runner's concurrent setting is > 1
• names :
  • can be up to 255 characters long
  • should be unique (not mandatory, but can cause problems)
• There are some special job types :
  • manual jobs can only be launched by a user action.
  • delayed jobs pause before executing scripts

personal access token

ID to authenticate with the GitLab API. Get yours.

pipeline

• top-level component of CI / CD
• Pipelines have
  1. jobs
  2. stages

rules (rules)

• are conditions to include/exclude jobs to/from pipelines (i.e. run those jobs or not)
• are evaluated
  • when the pipeline is created
  • in order
  • when a match is found
    • the corresponding job is included to / excluded from the pipeline
    • no more rules are checked
    if none of the rules matches, the job is not added to the pipeline

runner (https://docs.gitlab.com/ci/runners/, https://docs.gitlab.com/runner/)

• isolated + ephemeral VM / cloud instance that executes jobs
• each runner, as it becomes available, continually sends requests to the GitLab instance, asking to be assigned jobs

stage (vegastack.com, medium.com)

.gitlab-ci.yml has stages and stage keywords (see sample .gitlab-ci.yml)

• define when to run jobs : conditional execution of groups of tasks. For example :
  1. compile code
  2. if ok, run tests
• stages / jobs :
  • jobs in the same stage run in parallel
  • jobs in the next stage run after the jobs from the previous stage complete successfully
• stages defaults to

  .pre
  build
  test
  deploy
  .post