Azure DevOps: If Statements in Your YAML Pipelines

If Statements are a fantastic feature in YAML pipelines that allows you to dynamically customize the behavior of your pipelines based on the parameters you pass. They use syntax found within the Microsoft Conditions Documentation. Let's dive in and talk about how you can add them to your pipelines.

Constraints: Where You Can Use If Statements

You cannot use if statements everywhere within your YAML. You'll want to use them only prior to Stages, Jobs, Tasks, and Variables.

Using an if statement within the parameters of a job will not work.

Examples: How to Use If Statements

Simple If Statement

parameters:
  version: ""
jobs
- job: build
  displayName: "Build .NET Application
  pool: 
    vmImage: "ubuntu-latest"
  steps:
    - ${{ if ne(parameters.version, '1.0') }}:
        - script: "echo 'success!'"

If/And Statement

parameters:
  version: ""
jobs
- job: build
  displayName: "Build .NET Application
  pool: 
    vmImage: "ubuntu-latest"
  steps:
    - ${{ if and(
                 ne(parameters.version, '1.0'), 
                 ne(parameters.version, '2.0')
                ) }}:
        - script: "echo 'success!'"

If/And/Or Statment

parameters:
  version: ""
jobs
- job: build
  displayName: "Build .NET Application
  pool: 
    vmImage: "ubuntu-latest"
  steps:
    - ${{ if or(
                and(ne(parameters.version, '1.0'), 
                    ne(parameters.version, '2.0')),
                eq(parameters.version, '1.1')
               ) }}:
        - script: "echo 'success!'"

Syntax: Available If Statment Expressions

Here is a selection of the most common expressions I use regularly. For the full list, check out Microsoft's Documentation on them.

and

and(

eq(parameters.version, '1.0'), eq(parameters.version, '2.0')

)

or or(

eq(parameters.version, '1.0'), eq(parameters.version, '2.0')

)

ne

ne(parameters.version, '1.0')

eq

eq(variables.version, '1.0')

contains

contains(variables.version, '1')

startsWith

startsWith(variables.version, '1')

endsWith

endsWith(variables.version, '.2')

ge (Greater Than or Equal To)

ge(variables.version, 1)

gt (Greater Than)

gt(variables.version, 1)

le (Less Than or Equal To)

le(variables.version, 2)

lt (Less Than)

lt(variables.version, 2)