Sharing Variables within Tasks in Azure CI Pipeline
Do you want to create one variable in task-1 and read the value of that variable in task-2 in your azure ci pipeline? If your answer is yes then read this article.
I will show you how to get new build number from node.js. Then we will use the new build number in another task to update the azure pipeline build number.
azure devops setvariable task
We will write expression to run inbuilt task from azure pipeline to set new
variable. When we run script from azure pipeline then basically it is a
command line script you are running in windows command prompt.
echo '##vso[task.setvariable variable=one]secondValue'
- steps
- script : |
echo "##vso[task.setvariable variable=name]Rupesh"
- script : echo "My Name is $(name)" # it will print Rupesh
Notice we are using
Macro Syntax
to access the variable name. 
Notice I have read the variable name in
next task. If I would read the variable on the first task it will print empty.
So any task that assigns pipeline variables those are only accessible in next
task onwards only.
Creating Pipeline Variable in Azure pipeline Task
Lets create newBuildNumber variable that we are getting from node.js script.
As we know when you create a pipeline level variable in a task then
within the same task you will not be able to access that pipeline variable
within same task. Therefore, always when you create a pipeline variable then try
to always create new task to read that variable and do other task. Therefore, we
are printing the value using task scoped variable $num on “Create New
Variable” task.
In below example I am using build.js file to get new build number. Read “Calling Node.js Script from Azure Devops CI Pipeline” to know how am I returning build id from build.js file.
Create below task and note we are using setvariable task to create
newBuildNumber variable.
- script: |
echo "old buildnumber ~>$(Build.BuildNumber)"
export num=$(node ./build.js $(Build.BuildId) $(Build.SourceBranchName))
echo "##vso[task.setvariable variable=newBuildNumber]$num"
echo "Created new variable 'newBuildNumber' with value $num"
displayName: 'Creating New Variable'
enabled: true
Accessing Pipeline Variable in Azure pipeline Task
Remember when you are accessing a pipeline variable that is shared across
task then you must use
Macro Syntax
means $(newBuildNumber).
In this example I am using $(newBuildNumber) to access/read pipeline scoped
newBuildNumber variable created from previous task.
We are updating the build number of the azure pipeline.
- script: |
echo "Accessing NewBuild Number Variable $(newBuildNumber) & Updating Build Number of Pipeline"
echo "##vso[build.updatebuildnumber]$(newBuildNumber)"
displayName: 'Update Build Number'
enabled: true
Displaying new Build number of azure pipeline
In order to display updated build number I will use Build.BuildNumber
- script: echo "new buildnumber ~>$(Build.BuildNumber)"
displayName: 'Display New Build Number'
enabled: true
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