Creating a Pipeline

We will embark on a comprehensive journey through a complete pipeline, with each individual task covered in its tutorial. This approach aims to provide a detailed understanding of each task and how they collectively contribute to the functionality of pipeline-as-code.

In modern software development practices, pipelines play a crucial role in automating and streamlining the process of building, testing, and deploying applications. This tutorial will guide you through creating a pipeline using pipeline-as-code concepts. We'll focus on GitHub as the provider and assume you have a SAAP set up with pipeline-as-code capabilities.

Now that we have completed all the prerequisites to run this pipelineRun, we can continue by adding a pipeline to our application using pipeline-as-code approach.

Objectives

• Create a Tekton PipelineRun using a .tekton/pullrequest.yaml file from a code repository.
• Define parameters, workspaces, and tasks within the PipelineRun for building and deploying your application.

Key Results

• Successfully create and execute the Tekton PipelineRun using the defined .tekton/pullrequest.yaml file, enabling automated CI/CD processes for your application.

Tutorial

Create PipelineRun with Git Clone Task

Let's walk you through creating a Tekton PipelineRun using a Pipeline-as-Code approach.

1. Create a .tekton folder at the root of your repository.
2. Now add a file named pullrequest.yaml in this folder and place the below given content in it. This file will represent a PipelineRun.

  apiVersion: tekton.dev/v1beta1
  kind: PipelineRun
  metadata:
    name: git-clone
    annotations:
      pipelinesascode.tekton.dev/on-event: "[pull_request]" # Trigger the pipelineRun on pull_request events on branch main
      pipelinesascode.tekton.dev/on-target-branch: "main"
      pipelinesascode.tekton.dev/task: "[git-clone]" # The tasks will be fetched from Tekton Hub. We can also provide direct links to yaml files
      pipelinesascode.tekton.dev/max-keep-runs: "2" # Only remain 2 latest pipelineRuns on SAAP
  spec:
    params:
      - name: repo_url
        value: "{{body.repository.ssh_url}}" # Place your repo SSH URL
      - name: git_revision
        value: "{{revision}}" # Dynamic variable to fetch branch name of the push event on your repo
      - name: repo_name
        value: "{{repo_name}}" # Dynamic varaible to fetch repo name
      - name: repo_path
        value: "review-api" # Dynamic varaible for app name
      - name: git_branch
        value: "{{source_branch}}"
      - name: pull_request_number
        value: "{{pull_request_number}}"
      - name: organization
        value: "{{body.organization.login}}"
    pipelineSpec: # Define what parameters will be used for pipeline
      params:
        - name: repo_url
        - name: git_revision
        - name: repo_name
        - name: repo_path
        - name: pull_request_number
        - name: organization
        - name: git_branch
      workspaces: # Mention what workspaces will be used by this pipeline to store data and used by data transferring between tasks
        - name: source
        - name: ssh-directory
      tasks: # Mention what tasks will be used by this pipeline
        - name: fetch-repository #Name what you want to call the task
          taskRef:
            name: git-clone # Name of tasks mentioned in tekton-catalog
            kind: ClusterTask
          workspaces: # Mention what workspaces will be used by this task
            - name: output
              workspace: source
            - name: ssh-directory
              workspace: ssh-directory
          params: # Parameters will be used by this task
            - name: depth
              value: "0"
            - name: url
              value: $(params.repo_url)
            - name: revision
              value: $(params.git_revision)
    workspaces: # Mention Workspaces configuration
      - name: source
        volumeClaimTemplate:
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 2Gi
      - name: ssh-directory # Using ssh-directory workspace for our task to have better security
        secret:
          secretName: git-ssh-creds # Created this secret earlier
      - name: repo-token
        secret:
          secretName: git-pat-creds

1. Provide values for image_registry, and helm_registry parameters. You can find the urls from here. image_registry url should be succeeded by your application name. Example: nexus-docker-stakater-nexus.apps.lab.kubeapp.cloud/review-api

2. Now create a pull request on the repository with these changes. This should trigger a pipeline on your cluster.

3. You can go to your tenant's build namespace and see the pipeline running.

Exploring the Git Clone Task

The Git Clone task serves as the initial step in your pipeline, responsible for fetching the source code repository. Let's break down the key components:

1. name: fetch-repository: This names the task, making it identifiable within the pipeline.

2. Task Reference (taskRef): The Git Clone task is referred to using the name git-clone, which corresponds to a Task defined in the Tekton Catalog. This task knows how to clone a Git repository.

3. Workspaces (workspaces): The task interacts with two workspaces;output and ssh-directory. The output workspace will store the cloned repository, while the ssh-directory workspace provides SSH authentication. This means that the private key stored in the secret nordmart-ssh-creds will be utilized during the cloning process.

4. Parameters (params):

depth: Specifies the depth of the Git clone. A value of "0" indicates a full clone.

url: The URL of the source code repository. This parameter is dynamically fetched from the repo_url parameter defined in the PipelineRun.

revision: The Git revision to fetch, often corresponding to a specific branch or commit. This parameter is also dynamically fetched from the git_revision parameter in the PipelineRun.

Great! Let's add more tasks in our pipelineRun in coming tutorials.