Automating builds and implementing branch policies are critical for maintaining quality in a CI/CD pipeline. In this article, we’ll explore the different types of build triggers, how to configure them, and how to set up branch policies to enforce best practices, streamline reviews, and ensure only quality code is merged into main branches.

Understanding Build Triggers in Azure Pipelines

Build triggers define when a pipeline should automatically start:

  • Continuous Integration (CI) Trigger: Initiates a build whenever code is pushed to a specified branch.
  • Pull Request (PR) Trigger: Runs a build when a pull request is created or updated, verifying changes before merging.
  • Scheduled Trigger: Configures a pipeline to run at specific times (e.g., nightly builds or weekly checks).
  • Manual Trigger: Allows manual pipeline execution, often used for ad-hoc builds or custom testing.

Step 1: Configuring Continuous Integration Triggers

Setting up CI triggers ensures that code changes are automatically validated with each commit:


trigger:
  branches:
    include:
      - main
      - develop

This configuration triggers a build whenever code is pushed to the main or develop branches.

Step 2: Setting Up Pull Request Triggers

PR triggers validate code changes before they’re merged, helping maintain code quality:


pr:
  branches:
    include:
      - main

In this example, the pipeline runs whenever a pull request is created for the main branch, ensuring changes meet quality standards before merging.

Step 3: Configuring Scheduled Triggers

Scheduled triggers allow you to run pipelines at specific intervals, providing regular code checks:


schedules:
  - cron: "0 0 * * 0" # Runs every Sunday at midnight
    displayName: Weekly Build
    branches:
      include:
        - main

This configuration sets up a weekly build on Sunday at midnight, useful for tasks like running comprehensive tests or generating reports.

Setting Up Branch Policies in Azure Repos

Branch policies are rules applied to specific branches to ensure code quality:

  • Code Review Requirements: Enforces a minimum number of approvals before merging.
  • Build Validation: Requires that the pipeline passes before changes are merged.
  • Work Item Linking: Ensures code changes are associated with work items for traceability.
  • Status Checks: Allows integration with third-party tools that must pass before a merge.

Step 4: Enforcing Build Validation in Branch Policies

Build validation prevents merging code that hasn’t passed the required checks:

  1. Go to Branch Policies: In Azure Repos, navigate to “Branches” and select the branch (e.g., main) where you want to enforce policies.
  2. Add Build Policy: Under “Policies,” select “Build Validation” and choose the pipeline to validate builds for this branch.
  3. Set Trigger Conditions: Configure trigger conditions, like automatic validation on every PR update.

Step 5: Setting Required Reviewers

Code reviews ensure that multiple team members review changes, reducing errors:

  1. Enable Required Reviewers: Under branch policies, add a policy for “Minimum number of reviewers.”
  2. Set Reviewer Count: Specify the minimum number of approvals needed for a pull request to be merged.
  3. Bypass Permissions (optional): Optionally, allow certain users to bypass review requirements for urgent updates.

Step 6: Enabling Status Checks

Status checks integrate with external tools, ensuring other validations are met:

  • Third-Party Integrations: Set up checks with tools like SonarQube for code quality or security checks.
  • Define Required Checks: Under branch policies, configure “Status checks” to block merges until checks pass.

Best Practices for Build Triggers and Branch Policies

To optimize quality control with build triggers and branch policies, consider the following:

  • Limit CI Triggers to Active Branches: Set triggers on branches where active development occurs, like main or develop.
  • Enforce Review Policies Consistently: Apply the same review policies across critical branches to maintain consistency.
  • Monitor Build Health: Regularly review build logs to detect and address recurring issues.

Conclusion

Build triggers and branch policies are essential for maintaining code quality in Azure DevOps. By automating builds and enforcing reviews, you can ensure that only well-tested and reviewed code reaches your production environment. As you continue refining your CI/CD pipeline, these quality control measures will help create a reliable, efficient development process.