Calling Node.js Script from Azure CI Pipeline

If you want to run node.js script from azure-pipelines.yml and get the value returned from node.js script and use it in your CI next task. Then read this article. Example: I wanted to get new build number as per my package.json next version by running node script and update my CI pipeline build number.

Introduction

In this article I will show:

• How can you call build.js file to create new build number using package.json file & Azure CI pipeline build Id.
• Then update Azure CI pipeline build number with the returned new build number.
• Our new build number should be like <buildId>-<branchname> example: 123-main or 123-feature1

Creating JavaScript to create new Build Number

Create build.js file and here we will take buildId and branch-name as parameter passed from azure-pipelines.yml file.

Then we will increase the build id by one and add branch name and use that as new Build Number.

const buildId = process.argv[2];
const sourceBranchName = process.argv[3];
const newVersion = `${+buildId + 1}-${sourceBranchName}`;

console.log(newVersion); //Console Log will return the new version to Azure Pipelines. 

Therefore, do not write console log in your script which you don't want to pass to azure pipeline.

Creating Azure Pipelines file

Note: When you are creating a variable that is scoped within a single task. Then

• use export to set a variable
• And use $variable syntax to access variable value.

In below example we create num variable and we use $num to read the value of the variable.

trigger:
- main

steps:
# calling node.js script
- script: |
    export num=$(node ./build.js $(Build.BuildId) $(Build.SourceBranchName))
    echo "node.js returned $num"
  displayName: 'Executing Node.js script'

Running Azure CI Pipeline

Returning multiple value from Node.js to Azure pipeline

In order to return one value make sure just do single console.log and you will return exactly that value. Just like we did for build number above.

In order to return multiple values to Azure pipeline from node.js script. Don't write multiple console.logs.

For example if u want to return build and test command to azure pipeline then use below syntax in your node.js script file.

console.log({
build: 'npm run build',
test: 'npm test'
})

Updating the Build Number with new build number given by node.js script

We will use "##vso[build.updatebuildnumber]$newNumber" script to update build number.

Add script to update the build number in the Azure pipelines

- script: |
    echo "old buildnumber ~>$(Build.BuildNumber)"
    export num=$(node ./build.js $(Build.BuildId) $(Build.SourceBranchName))
    echo "node.js returned $num"
    echo "##vso[build.updatebuildnumber]$num"
  displayName: 'Update Build Number'

Add another new script to show the build number.

- script:  echo "new buildnumber ~>$(Build.BuildNumber)"
  displayName: 'Display New Build Number'

Updating build number Displaying new build number

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