If / Else logic and custom variables-CodePudding

I'm trying to run some if / else logic in my pipelines using expressions.

trigger:
  - dev
  - qa
  - main
  - test/*

resources:
  - repo: self

variables:
  vmImageName: 'ubuntu-latest'
  # We get rid off the 'refs/heads/' to isolate the branch name and deduce the environment we're running on.
  # If running on 'main' branch, env value will be 'prod'.
  env: $[replace(replace(variables['Build.SourceBranchName'], 'main', 'prod'), 'refs/heads/', '')]

stages:
  - stage: Build
    displayName: Build stage
    jobs:
      - job: Build
        displayName: Build
        pool:
          vmImage: $(vmImageName)
        steps:
          - script: | # this below block works as expected            
              if [[ $(env) == "dev" ]] ; then
                echo "dev"
              elif [[ $(env) == "qa" ]] ; then
                echo "qa"
              elif [[ $(env) == "prod" ]] ; then
                echo "prod"
              else 
                echo "We are running on an unmanaged branch"
              fi
            displayName: Test 1        
          - script: echo "Deploying to $(env)"
            ${{ if in(variables['env'], 'prod', 'qa', 'dev') }}:
              displayName:  Deploy to a managed environment # we never get there
            ${{ else }}:
              displayName: Deploy to an unmanaged environment # always here

I have tried both variables['env'] and variables.env syntax as stated here but no more luck.

Any idea why my implementation doesn't work ? I think I could be using the system's variables['Build.SourceBranchName'] into that if/else statement but I would like to understand what's wrong with my code.

CodePudding user response：

It because the $[replace(replace(variables['Build.SourceBranchName'], 'main', 'prod'), 'refs/heads/', '')] is a runtime expression, and the displayName is evaluated before the runtime - when the YAML file is compiled into a plan.

This is why Build.SourceBranchName will work for you, because this variable is evaluated before the runtime.