Can Conditional Variable Assignment be Done in Azure Pipelines?

Question

Azure Pipelines has Expressions and Conditions, but I can find no way to assign one of two values to a variable, based on a condition.

Is there any way to accomplish what this pseudo-code would?

    ${{ if endsWith( variables['Build.SourceBranchName'], '/master' ) }}: 
      buildVersion: variables['mavenVersion']
    ${{ else }}: 
      buildVersion: variables['Build.SourceBranchName']

Answer 1

As an extension to @Mike Murray's answer, if you are using variable groups you must define additional variables as name value pairs. To use conditional variable assignment in this case would be as follows:

variables:
- group: 'my-variable-group'
- name: myfirstadditionalvariable
  value: 100
- name: myconditionalvariable
  ${{ if eq( variables['Build.SourceBranchName'], 'master' ) }}: 
    value: masterBranchValue
  ${{ if ne( variables['Build.SourceBranchName'], 'master' ) }}: 
    value: featureBranchValue

Answer 2

I was closer than I thought. This is not pretty, but it worked. (with more yaml context)

variables:
  ${{ if eq( variables['Build.SourceBranchName'], 'master' ) }}: 
    buildVersion: ${{ variables['mavenVersion'] }}
  ${{ if ne( variables['Build.SourceBranchName'], 'master' ) }}: 
    buildVersion: ${{ variables['Build.SourceBranchName'] }}

  buildKey: ${{ format('{0}_{1}', variables['supportReleaseNumber'], variables['buildVersion']) }}
  buildNum: $[counter(variables['buildKey'], 1)]  # same as $(Rev:r), but more widely usable 

name: $(buildKey)_$(buildNum)  # build run name

Answer 3

This should do the trick....

BuildVersion is initialised as $(Build.SourceBranch) if it's the master branch you change that to the $(mavenVersion) else no change.

variables:
  mavenVersion: '1.0'
  buildVersion: $(Build.SourceBranch)

pool:
  vmImage: 'ubuntu-latest'

steps:

- script: echo '##vso[task.setvariable variable=buildVersion]$(mavenVersion)'
  displayName: "Set the buildVersion as mavenVersion if the Build.SourceBranch = 'refs/heads/master' "
  condition: eq(variables['Build.SourceBranch'], 'refs/heads/master')

- script: echo $(buildVersion)
  displayName: 'Printing the variable'

non-master branches prints 'refs/heads/branch_name' which is mavenVersion

master branch prints 1.0 which is mavenVersion