Azure DevOps REST api - Run pipeline with variables - azure-devops

Question

I have a pipeline on Azure Devops that I'm trying to run programatically/headless using the REST api: https://learn.microsoft.com/en-us/rest/api/azure/devops/pipelines/runs/run%20pipeline?view=azure-devops-rest-6.0
So far so good, I can auth and start a run. I would like to pass data to this pipeline which the docs suggests is possible using variables in the request body. My request body:
{
"variables": {
"HELLO_WORLD": {
"isSecret": false,
"value": "HelloWorldValue"
}
}
}
My pipeline YAML looks like this:
trigger: none
pr: none
pool:
vmImage: 'ubuntu-latest'
steps:
- task: Bash#3
inputs:
targetType: 'inline'
script: |
KEY=$(HELLO_WORLD)
echo "Hello world key: " $KEY
This however gives me an error that "HELLO_WORLD: command not found".
I have tried adding a "HELLO_WORLD" variable to the pipeline and enabled the "Let users override this value when running this pipeline"-setting. This results in the HELLO_WORLD variable no longer being unknown, but instead its stuck on its initial value and not set when i trigger a run with the REST api
How do you pass variables to a pipeline using the REST api? It is important that the variable value is set only for a specific run/build
I found another API to run a build, but it seems like you cannot use Personal Access Token auth with it, like you can with the pipeline api - only OAuth2 - https://learn.microsoft.com/en-us/rest/api/azure/devops/build/builds/queue?view=azure-devops-rest-6.0

Answer 1

You can do it with both the Runs API and Build Queue API, both work with Personal Access Tokens. For which one is the better/preferred, see this question: Difference between Azure Devops Builds - Queue vs run pipeline REST APIs, but in short the Runs API will be the more future proof option
Option 1: Runs API
POST https://dev.azure.com/{{organization}}/{{project}}/_apis/pipelines/{{PipelineId}}/runs?api-version=6.0-preview.1
Your body will be of type application/json (HTTP header Content-Type is set to application/json) and similar to the below, just replace resources.repositories.self.refName with the appropriate value
{
"resources": {
"repositories": {
"self": {
"refName": "refs/heads/main"
}
}
},
"variables": {
"HELLO_WORLD": {
"isSecret": false,
"value": "HelloWorldValue"
}
}
}
Option 2: Build API
POST https://dev.azure.com/{{organization}}/{{project}}/_apis/build/builds?api-version=6.0
Your body will be of type application/json (HTTP header Content-Type is set to application/json), something similar to below, just replace definition.id and sourcebranch with appropriate values. Please also note the "stringified" content of the parameter section (it should be a string representation of a json map)
{
"parameters": "{\"HELLO_WORLD\":\"HelloWorldValue\"}",
"definition": {
"id": 1
},
"sourceBranch": "refs/heads/main"
}

Answer 2

Here's the way I solved it....
The REST call:
POST https://dev.azure.com/<myOrg>/<myProject>/_apis/pipelines/17/runs?api-version=6.0-preview.1
 
The body of the request:
{
    "resources": {
        "repositories": {
            "self": {
                "refName": "refs/heads/main"
            }
        }
    },
    "templateParameters": {
        "A_Parameter": "And now for something completely different."
    }
}
Note: I added an authorization header with basic auth containing a username (any name will do) and password (your PAT token value). Also added a Content-Type application/json header.
 
Here's the entire yaml pipeline I used:
 
parameters:
- name: A_Parameter
  displayName: A parameter
  default: noValue
  type: string
 
trigger:
- none
 
pool:
  vmImage: ubuntu-latest
 
steps:
 
- script: |
    echo '1 - using dollar sign parens, p dot A_Parameter is now: ' $(parameters.A_Parameter)
    echo '2 - using dollar sign double curly braces, p dot A_Parameter is now::' ${{ parameters.A_Parameter }} '::'
    echo '3 - using dollar sign and only the var name: ' $(A_Parameter)
  displayName: 'Run a multi-line script'
 
 
And here's the output from the pipeline log. Note that only the second way properly displayed the value.  
 
1 - using dollar sign parens, p dot A_Parameter is now: 
2 - using dollar sign double curly braces, p dot A_Parameter is now:: And now for something completely different. :: 
3 - using dollar sign and only the var name: