Azure Pipelines Conditional and Persistent Variables

Question

I'm trying to setup an Azure Pipeline that automatically updates version numbers based on which branch is being built. Given a master branch, a develop branch, and a version in the form {major.minor.patch.build} I want to achieve the following:

Whenever the pipeline is triggered by master:

patch is incremented by 1
build is reset to 0

Whenever the pipeline is triggered by develop:

build is incremented by 1

An example of what I expect the version numbers to look like after multiple runs assuming a starting version of 1.0.0.0:

Run 1 on develop: 1.0.0.1
Run 2 on develop: 1.0.0.2
Run 3 on master: 1.0.1.0
Run 4 on master: 1.0.2.0
Run 5 on develop: 1.0.2.1
Run 6 on develop: 1.0.2.2
Run 7 on master: 1.0.3.0

My first thought was to use a counter for the patch and build values but there doesn't seem to be a way of conditionally incrementing them or resetting the counter. My next thought was to use a couple script tasks that execute conditionally based on the branch, such as:

    #Update build
    - powershell: echo "##vso[task.setvariable variable=version.build;isOutput=true]$(version.build + 1)"
      condition: eq(variables['Build.SourceBranch'], 'refs/heads/develop')

    #Reset build number
    - powershell: echo "##vso[task.setvariable variable=version.build;isOutput=true]0"
      condition: eq(variables['Build.SourceBranch'], 'refs/heads/master')

    #Update patch
    - powershell: echo "##vso[task.setvariable variable=version.patch;isOutput=true]$(version.patch + 1)"
      condition: eq(variables['Build.SourceBranch'], 'refs/heads/master')

However that approach isn't persistent across runs (not to mention $(version.patch + 1) doesn't work. I can't find any information on how to actually increment a variable in this way). My last idea was to have a version file in the repository and use that but I really don't want to have to go down that route.

Is there a way to achieve what I'm looking for using Pipelines or am I barking up the wrong tree trying to go about it this way?

Edit I should have mentioned in the question that at this point I have a pipeline setup that builds my application but does nothing with versioning. What I'm looking for at this point is a way to dynamically update a few persistent variables/values (specifically patch and build).

Levi Lu-MSFT · Accepted Answer

I have a workaround to achieve this with restful api.

For example you want to add above version tag to the build. You can first get the tag of the previous build with get tag api. Then you can update the version with the scripts and update it with updated tag. You can refer to below scripts in the powershell task.

# first get previous build id

$url = "$(System.TeamFoundationCollectionUri)$(System.TeamProject)/_apis/build/builds?definitions={pipeline Id}&`$top=2&api-version=5.1"

$result = Invoke-RestMethod -Uri $url -Headers @{authorization = "Bearer $(System.AccessToken)"} -Method get

$builds = $result.value
$bid = $builds[1].id

# get the build tag with get build tag api

$urltag ="$(System.TeamFoundationCollectionUri)$(System.TeamProject)/_apis/build/builds/$bid/tags?api-version=5.1"

$tagResult = Invoke-RestMethod -Uri $urltag -Headers @{authorization = "Bearer $(System.AccessToken)"} -Method get

# get the tag and update it

if($tagResult.value)
{
   $tagarr = [regex]::split($result.value, '\.')
   $patch = $tagarr[2]
   $build = $tagarr[3]
   $tag=""
   if("$(Build.SourceBranch)" -eq "refs/heads/master")
   {
      $patch = [int]$patch + 1
      # update the variables version.patch and version.build with below scripts, so that it can be referenced in the following tasks.
      #echo "##vso[task.setvariable variable=version.patch;isOutput=true]$patch"
      #echo "##vso[task.setvariable variable=version.build;isOutput=true]0"

     $tag = "$(version.major).$(version.minor).$patch.0"    
   }  
   if("$(Build.SourceBranch)" -eq "refs/heads/dev")
   {
      $build= [int]$build+ 1
      #echo "##vso[task.setvariable variable=version.patch;isOutput=true]$patch"
      #echo "##vso[task.setvariable variable=version.build;isOutput=true]$build"
      $tag = "$(version.major).$(version.minor).$patch.$build"  
   }

 #add $tag to current build.
  $urltagupdate = "$(System.TeamFoundationCollectionUri)$(System.TeamProject)/_apis/build/builds/$(Build.BuildId)/tags/$($tag)?api-version=5.1"

  Invoke-RestMethod -Uri $urltagupdate -Headers @{authorization = "Bearer $(System.AccessToken)"} -Method put

}else 
{
  #if the build is run for the first time and the tag is not exist.
  #you can omit this part by manually creating a initial tag for the build.

  $tag = ""
  if("$(Build.SourceBranchName)" -eq "refs/heads/master")
  {
    $tag = "1.0.1.0"
  }
  if("$(Build.SourceBranchName)" -eq "refs/heads/dev") 
  {
    $tag="1.0.0.1"
  }

 #add $tag to current build.

  $urltagupdate = "$(System.TeamFoundationCollectionUri)$(System.TeamProject)/_apis/build/builds/$(Build.BuildId)/tags/$($tag)?api-version=5.1"

  Invoke-RestMethod -Uri $urltagupdate -Headers @{authorization = "Bearer $(System.AccessToken)"} -Method put

}

Above is an example for build tags. If you want to tag repo branch you can use refs tag api.

The main idea is to get the previous tag via api and update the version.patch and version.build according to the build.sourcebranch in a powershell task.

Azure Pipelines Conditional and Persistent Variables

Answers (2)

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