The .gitlab-ci.yml File¶

Why?¶

The pipeline requirements for our application consist of a need to compile it, package it up and then store it in a centralised location we can fetch it from at a later date. Once this pipeline has completed we'll have a package of our application ready for the Ansible pipeline to pull and pass to Ansible.

Breakdown¶

These are our stages:

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stages:
  - build
  - publish
  - deploy

The Build¶

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build:
  stage: build
  rules:
    - changes:
        - "*.go"
  artifacts:
    paths:
      - "httpcats.zip"
    expire_in: 1 day
  script:
    - apt update && apt install zip -y
    - go build -v -o "httpcats"
    - zip -r httpcats.zip httpcats static

artefacts¶

After we've built the application we need to produce an artefact for the next stage.

Expiring artefacts¶

We're using something we haven't seen before: expire_in: inside of the artefacts:. This means the artefact will be deleted from the pipeline's cache after the stated time and will no longer be available for download. This is a good idea if you're managing your own CI Runners and disk space is limited.

Rules¶

We're stating that we only want the pipeline to begin in the event there were changes to .go files. This makes sense, because I don't want to trigger a deployment if there is nothing new to deploy.

Script¶

This is the core functionality of this job: compiling and packaging the application binary and static files.

We install ZIP inside the Docker container that's running the job. It's not present by default. We build our application using the go binary. And then we create the .zip file we need to deploy everything to our servers and serve content.

Publishing the Application¶

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publish:
  stage: publish
  rules:
    - changes:
        - "*.go"
  dependencies:
    - build
  script:
    - 'curl --header "JOB-TOKEN: $CI_JOB_TOKEN" --upload-file httpcats.zip "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/generic/httpcats/deployment/httpcats.zip"'

Dependency¶

We require the ZIP file from the build job within the same pipeline, otherwise we'll have nothing to deploy. That's what we're doing here: pulling that ZIP file (the dependency) in from the other job.

Rules¶

As above, we only add this stage into the pipeline if a .go file has been manipulated and pushed into the commit.

Script¶

We're using a simple curl command to push our ZIP file to the built in GitLab Package Repository. We're using the "Generic" repository as we're not pushing a language or platform specific package.

We're not using a version for our deployment at this point in time as we're keeping things simple, but in short: when we pull this file from the Package Repository we get the last version that was pushed (based on the date/time it was pushed I believe), so we always get the latest.

The Solution¶

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image: golang:latest

stages:
  - build
  - publish
  - deploy

build:
  stage: build
  rules:
    - changes:
        - "*.go"
  artifacts:
    paths:
      - "httpcats.zip"
    expire_in: 1 day
  script:
    - apt update && apt install zip -y
    - go build -v -o "httpcats"
    - zip -r httpcats.zip httpcats static

publish:
  stage: publish
  rules:
    - changes:
        - "*.go"
  dependencies:
    - build
  script:
    - 'curl --header "JOB-TOKEN: $CI_JOB_TOKEN" --upload-file httpcats.zip "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/generic/httpcats/deployment/httpcats.zip"'

deploy:
  stage: deploy
  variables:
    TARGET_PROJECT: $CI_PROJECT_ID
  rules:
    - changes:
        - "*.go"
  trigger: devops-uncovered-book/book-configuration-ansible

Committing the Code¶

1. Set your working directory to the application/httpcats repository
2. Save the file as .gitlab-ci.yml and use git add .gitlab-ci.yml to add it to the Git staging area
3. Use git commit -am 'providing a CI pipeline for our application' to commit the file to our repository
4. Push the code to GitLab.com: git push