Stages Dependencies and Conditions

In this guide, we explore how stages, dependencies, and conditions work together to create flexible, reliable CI/CD pipelines in Azure DevOps. By mastering these concepts, you’ll ensure your code moves smoothly from development through testing and into production with minimal manual intervention.

Defining Stages and Dependencies in Azure Pipelines

Stages represent the major phases of your pipeline (for example, Build, Test, and Deploy). By default, these stages run in the order they’re defined, but you can customize their execution sequence with the dependsOn keyword. In the example below, the Deploy stage waits for both Build and Test to finish before starting:

stages:
  - stage: Build
    jobs:
      - job: build_app

  - stage: Test
    jobs:
      - job: run_tests

  - stage: Deploy
    dependsOn:
      - Build
      - Test
    jobs:
      - job: deploy_app

Each stage can contain multiple jobs (such as build_app, run_tests, and deploy_app) that run in parallel or sequence according to your configuration.

Using Conditions for Conditional Execution

Conditions add intelligence to your pipeline by allowing stages, jobs, or steps to run—or be skipped—based on branches, variables, or the outcomes of previous tasks. You define these checks using the condition keyword. For example, you may want to deploy to production only when the pipeline runs on the main branch and every prior stage has succeeded.

Example: Branch-Aware Multi-Stage Pipeline

Below is a sample YAML that combines sequential stages with branch-based conditions. The Build stage compiles your code and runs unit tests, with an extra check to decide whether to proceed. The Deploy stage only triggers on refs/heads/main.

stages:
- stage: Build
  jobs:
  - job: BuildJob
    steps:
    - script: echo "Building the project"
      displayName: 'Build'
    - script: echo "Running unit tests"
      displayName: 'Run Tests'
    # Only proceed on the main branch
    - script: echo "Proceeding to deployment stage"
      displayName: 'Check Branch'
      condition: eq(variables['Build.SourceBranch'], 'refs/heads/main')

- stage: Deploy
  dependsOn: Build
  condition: succeeded()
  jobs:
  - job: DeployJob
    steps:
    - script: echo "Deploying the application"
      displayName: 'Deploy'
    # Add more deployment steps here

In this setup, Deploy runs immediately after Build, but only when the source branch is main. Otherwise, the deployment stage is skipped.

dependsOn vs condition: Side-by-Side Comparison

Best Practices for Stages, Dependencies, and Conditions

• Align stages with your development lifecycle (e.g., Build → Test → Deploy).
• Use dependsOn to enforce critical order or allow safe parallelism.
• Apply condition to skip unnecessary runs and save resources.

References

• Azure DevOps Pipelines Documentation
• Azure Pipelines YAML schema
• Variables in Azure Pipelines