In Azure DevOps, task conditions allow you to control when a particular task in your pipeline will run based on various criteria. This feature is essential for creating complex and flexible CI/CD workflows. Here’s an overview of how task conditions work and some common scenarios where they are used:

Types of Task Conditions in Azure DevOps

1. succeeded: The default condition. The task will run if all previous tasks in the job have succeeded.

2. succeededOrFailed: The task will run whether the previous tasks have succeeded or failed.

3. always: The task runs regardless of the success or failure of the previous tasks. Useful for cleanup tasks or for tasks that should always run, such as notifications.

4. failed: The task will run only if any of the previous tasks in the job have failed.

5. custom conditions: You can define custom conditions using expressions. For example, you might run a task only if a certain variable is set to a particular value.

Syntax for Task Conditions

Task conditions are specified using the condition keyword in the YAML pipeline. Here’s how you can use different types of conditions:

Common Scenarios for Using Conditions

1. Conditional Deployments: Run deployment tasks only if the build task succeeds and if the pipeline is triggered by a merge into the main branch.

2. Cleanup Tasks: Ensure that cleanup tasks run regardless of whether previous tasks succeeded or failed.

3. Environment-Specific Tasks: Run certain tasks only for specific environments (like staging or production) based on branch names or variables.

4. Manual Triggers: Execute certain tasks only when the build is triggered manually.

5. Failed Notifications: Send notifications or create work items only if the build or deployment fails.

Best Practices

• Use Descriptive Names: Use descriptive names for your tasks and conditions to make your YAML files easier to understand.

• Test Conditions: Thoroughly test the conditions in your pipeline to ensure they behave as expected.

• Document Conditional Logic: If your pipeline has complex conditional logic, document it either in the YAML file itself or in your project documentation to help others understand the flow.

• Optimize for Performance: Use conditions to skip unnecessary tasks, especially in scenarios like pull request builds or CI triggers, to save time and resources.

By using task conditions effectively, you can create more efficient, flexible, and robust Azure DevOps pipelines that cater to the specific needs of your development and deployment processes.