Conditionally add a tag to merge-commit using Azure DevOps and git

Question

I would like to basically achive the very same thing you could achive while using the built in "tag-functionality" for build in Azure DevOps, with one exception.. I need to add a tag conditionally.. The basic idea is to evanluate if the SourceBranch for my PR starts with refs/heads/hotfix, and that the target branch is refs/heads/master, then I would like to tag the final merged commit with the tag "hotfix".

I started with something like this:

    name: PR-$(Rev:r)

trigger: none

pool:
  vmImage: 'windows-latest'

jobs:
  - job: Say_hello_to_my_little_friend
    steps:
      - pwsh: Write-Host "Hello little friend!" 
  - job: Tag_As_Hotfix
    condition: and( eq(variables['System.PullRequest.TargetBranch'],'refs/heads/master'), startsWith(variables['System.PullRequest.SourceBranch'], 'refs/heads/hotfix'))
    steps:
      - pwsh: |
          git tag hotfix
          git push origin master
        displayName: Tag as hotfix

However.. I quickly reialized that the branch master doesnt exists, since during a PR Azure DevOps creates a temporary branch which it runs all the "checks" at. And even if the above would have worked.. I assume another issue would be that the tag would end up on the commit previous to the actuall merge-commit (or am I wrong?).. Any idea of how to add a tag conditionally to the merged-commit?

score 0 · Answer 1 · answered Nov 16 '20 at 08:28

When you set the build as the Build validation in Pull Request, the build will execute before completing the Pull Request. So it will not meet your requirements.

You could refer to this doc about Branch Policy.

Any idea of how to add a tag conditionally to the merged-commit?

Since the variable System.PullRequest.TargetBranch and System.PullRequest.SourceBranch only exist in the Pull Request Trigger Build, you could try the following Settings to set the pipeline. Create two pipelines: Pipeline 1 and Pipeline 2.

In Pipeline 1 , you could set the condition and use Rest API to trigger the pipeline 2.

In Pipeline 2, you could add an Environment in the Pipeline 2, and the Environment contains the check: Invoke Rest API to check the status of the Pull Request. If the API response meets the requirements(Pull Reuqest Status is completed), it will run the git command to add tag.

Here is my sample:

Pipeline 1:

trigger: none

pool:
  vmImage: 'windows-latest'

jobs:
  - job: Tag_As_Hotfix
    condition: and( eq(variables['System.PullRequest.TargetBranch'],'refs/heads/master'), startsWith(variables['System.PullRequest.SourceBranch'], 'refs/heads/test'))
    steps:
    - task: PowerShell@2
      inputs:
        targetType: 'inline'
        script: |
          $token = "PAT"
          
          $url="https://dev.azure.com/{Org}/{Project}/_apis/distributedtask/variablegroups/{VariableGroup ID}?api-version=5.0-preview.1"
          
          $token = [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes(":$($token)"))
          
          $JSON = @'
          {
             "variables": {
                 "id": {
                    "value": "$(SYSTEM.PULLREQUEST.PULLREQUESTID)"
               }
            },
            "type": "Vsts",
            "name": "New variable group 16-Nov"
          }
          '@
          
          $response = Invoke-RestMethod -Uri $url -Headers @{Authorization = "Basic $token"} -Method PUT -Body $JSON -ContentType application/json
    - task: PowerShell@2
      inputs:
        targetType: 'inline'
        script: |
          $token = "PAT"
          
          $url="https://dev.azure.com/{ORG}/{Project}/_apis/build/builds?api-version=5.0"
          
          $token = [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes(":$($token)"))
          
          $JSON = @'
          {
              "definition": {
                  "id": BuilddefinitionID
              }
          }
          '@
          
          $response = Invoke-RestMethod -Uri $url -Headers @{Authorization = "Basic $token"} -Method Post -Body $JSON -ContentType application/json

Note: You need to create a Variable Group to save the Pull Request ID. This id could be used in the Invoke Rest API check.

Pipeline2:

trigger:
- none

pool:
  vmImage: 'windows-latest'

stages:
- stage: deploy
  jobs:
  - deployment: DeployWeb
    displayName: deploy Web App
    environment: 'API Test'
    strategy:
      runOnce:
        deploy:
          steps:
          - script: |
              git tag hotfix
              git push origin master

Environment: Pipelines -> Environemnts-> Approvals and checks -> Invoke Rest API

Variable Group:

Workflow

Create Pull Request -> Trigger Pipeline 1 -> Trigger Pipeline2 and Update the ID in Variable Group -> Pipleline 2 check the Pull Request Status -> Run the command to Add Tag.

Conditionally add a tag to merge-commit using Azure DevOps and git

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