Access build pipeline output variable in Environment Approval / Check - azure-devops

Question

I am trying to build an automatic Environment Approval with Invoke Azure Function. I need to pass a variable that is created in a previous build stage. I have added the variable to the function body, but the variable is not evaluated:
Task that creates the output variable (in previous stage)
- task: CmdLine#2
inputs:
script: |
# Debug output (value visible in logs)
pulumi stack output resourceGroupName
echo "##vso[task.setvariable variable=resourceGroupName;isoutput=true]$(pulumi stack output resourceGroupName)"
workingDirectory: 'infra'
Body for the Azure function:
{ "ResourceGroup": "$(resourceGroupName)" }
Log:
2020-03-26T15:57:01.2590351Z POST https://azure-function-url
Request body: {
"ResourceGroup": "$(resourceGroupName)"
}

Answer 1

Added the variable to the function body, but the variable is not
evaluated
This is a expected action. Here what you are doing is share variable across stages, which does not supported directly until now.
Output variable just used to share values between steps instead of stages.
Work around:
If you want to use the generated variable in next stage, a workaround you can consider to use is writing the variable to a file, leveraging pipeline artifacts.
Sample steps:
Here I will pass one variable which name is resourceGroupName to next stage.
1) Create a folder which will contain the variables you want to pass
mkdir -p $(Pipeline.Workspace)/variables
2) Write the contents of the variable to file StageUsed:
echo "$resourceGroupName" > $(Pipeline.Workspace)/variables/StageUsed
3) In next stage, add one job before your InvokeAzureFunction job. Download the variables pipeline artifact that previous stage published.
4) Transfer each file into a variable:
resourceGroupName=$(cat $(Pipeline.Workspace)/variables/StageUsed)
5) Make the variable exposed in the current job, and set it reference name as Out:
echo "##vso[task.setvariable variable=resourceGroupName;isoutput=true]$resourceGroupName"
6) Now, you can access the variable in your InvokeAzureFunction job by calling dependencies.secondjob.outputs['output.resourceGroupName']
Sample Script:
trigger:
- master
pool:
vmImage: 'ubuntu-latest'
stages:
- stage: FirstStage
jobs:
- job: firstjob
pool:
vmImage: 'Ubuntu-16.04'
steps:
- bash: |
resourceGroupName="value"
mkdir -p $(Pipeline.Workspace)/variables
echo "$resourceGroupName" > $(Pipeline.Workspace)/variables/resourceGroupName
- publish: $(Pipeline.Workspace)/variables
artifact: variables
- stage: SecondStage
jobs:
- job: secondjob
pool:
vmImage: 'Ubuntu-16.04'
steps:
- download: current
artifact: variables
- bash: |
resourceGroupName=$(cat $(Pipeline.Workspace)/variables/resourceGroupName)
echo "##vso[task.setvariable variable=resourceGroupName;isoutput=true]$resourceGroupName"
name: output
- bash: |
echo "$(output.resourceGroupName)"
- job: ServerJob
dependsOn: secondjob
pool: server
variables:
resourceGroupName: $[dependencies.secondjob.outputs['output.resourceGroupName']]
steps:
- task: AzureFunction#1
inputs:
function:
method: 'POST'
body: '$(sdf)'
waitForCompletion: 'false'