Azure Pipeline – Each – If: Unlocking the Power of Conditional Execution

Are you tired of tedious pipeline scripting and cumbersome conditional logic? Do you wish you had a more elegant way to execute tasks only when certain conditions are met? Look no further! In this article, we’ll delve into the world of Azure Pipelines and explore the magic of using “Each” and “If” together to streamline your pipeline development.

What is Azure Pipelines?

Azure Pipelines is a continuous integration and continuous deployment (CI/CD) service offered by Microsoft Azure. It enables you to automate the build, test, and deployment of your software projects, leveraging a robust and flexible pipeline architecture. With Azure Pipelines, you can define a sequence of tasks that run in a specific order, allowing you to orchestrate complex workflows with ease.

What is the “Each” keyword?

The “Each” keyword in Azure Pipelines is a powerful construct that allows you to iterate over an array or object and execute a set of tasks for each item. This can be particularly useful when working with collections of environments, repositories, or other data structures. The “Each” keyword is often used in conjunction with the “If” keyword to add an additional layer of conditional logic.

Syntax and Example

steps:
  - task: Script@2
    displayName: 'Run script on each item'
    each:
      variable: item
      in: ${{ parameters.myArray }}
    script: |
      echo "Processing $(item)"
      # Perform some action on $(item)

In this example, the pipeline will iterate over the array stored in the “myArray” parameter and execute the script task for each item. The “each” keyword specifies the variable name (“item”) and the array to iterate over.

What is the “If” keyword?

The “If” keyword in Azure Pipelines is used to add conditional logic to your pipeline scripts. It allows you to evaluate an expression and execute a set of tasks only if the condition is true. This can be useful for bypassing tasks that are not applicable or skipping unnecessary steps.

Syntax and Example

steps:
  - task: Script@2
    displayName: 'Run script only if condition is true'
    if: eq(variables['myVar'], 'true')
    script: |
      echo "Condition is true, executing script"
      # Perform some action

In this example, the pipeline will execute the script task only if the “myVar” variable is set to “true”. The “if” keyword specifies the condition to evaluate, and the task will be skipped if the condition is false.

Combining “Each” and “If” for Conditional Execution

Now that we’ve covered the basics of “Each” and “If”, let’s explore how to combine them to achieve conditional execution on a per-item basis.

Example: Running a task only if a condition is true for each item

steps:
  - task: Script@2
    displayName: 'Run script on each item if condition is true'
    each:
      variable: item
      in: ${{ parameters.myArray }}
    if: eq(item.condition, 'true')
    script: |
      echo "Processing $(item) since condition is true"
      # Perform some action on $(item)

In this example, the pipeline will iterate over the “myArray” parameter and execute the script task only if the “condition” property of each item is set to “true”. This allows you to dynamically skip or execute tasks based on the properties of each item.

Use Cases for “Each” and “If” in Azure Pipelines

Now that we’ve covered the basics of “Each” and “If”, let’s explore some practical use cases for combining these keywords in Azure Pipelines:

• Environment deployment: Use “Each” to iterate over a list of environments and deploy an application only if the environment meets certain conditions (e.g., production, staging, or dev).
• Repository filtering: Use “If” to skip tasks for repositories that don’t meet specific criteria (e.g., public or private repos, specific branches, or certain file patterns).
• Dynamic task execution: Use “Each” and “If” to execute tasks only for specific items in an array or object, based on properties or conditions.
• Matrix build optimization: Use “If” to skip unnecessary build tasks for certain configurations, and use “Each” to iterate over a matrix of build configurations.

Best Practices for Using “Each” and “If” in Azure Pipelines

When using “Each” and “If” in Azure Pipelines, keep the following best practices in mind:

1. Keep it simple: Avoid nesting multiple “Each” and “If” statements, as this can lead to readability and maintenance issues.
2. Use descriptive variable names: Clearly label your variables and arrays to improve code readability and reduce errors.
3. Test and debug: Thoroughly test and debug your pipeline scripts to ensure correct behavior and handling of edge cases.
4. Document your pipeline: Include clear comments and documentation within your pipeline script to facilitate understanding and maintenance.

Keyword	Description
Each	Iterate over an array or object and execute tasks for each item
If	Evaluate a condition and execute tasks only if true

In conclusion, the combination of “Each” and “If” in Azure Pipelines provides a powerful way to execute tasks conditionally, based on the properties of individual items in an array or object. By following best practices and exploring creative use cases, you can unlock the full potential of Azure Pipelines and streamline your pipeline development.

Happy pipelining!

Frequently Asked Question

Get ready to master Azure Pipelines with Each and If statements! Here are the top 5 questions and answers to help you navigate these powerful features: