Parse Set variables output to template - Azure yml pipeline - azure-devops

Question

I have a pipeline that runs a template pipeline. It looks like this:
resources:
repositories:
- repository: repoName
type: git
name: projectName/repoName
ref: branchName
stages:
- stage: GetLastCommitId
jobs:
- job: lastCommitId
steps:
- checkout: repoName
- bash: |
cd repoName
echo "##vso[task.setvariable variable=commitId;isOutput=true]$(git rev-parse HEAD)"
name: a
- bash: |
echo $(a.commitId)
- checkout: self
- template: templates/bicep.yml
parameters:
environment: dev
lastCommitId: $[stageDependencies.GetLastCommitId.lastCommitId.outputs['a.commitId']]
bash returns me the required ID. Everything as it is meant to be.
Now I want to pass this output value to the template as parameter - lastCommitId.
Is there a way to do this?
Here's what I tried:
- template: templates/bicep.yml
parameters:
environment: dev
lastCommitId: $(a.commitId)
Error: Empty string
- template: templates/bicep.yml
dependsOn: GetLastCommitId
parameters:
environment: dev
lastCommitId: $[stageDependencies.GetLastCommitId.lastCommitId.outputs['a.commitId']]
Error: Can not start pipeline. dependsOn not expected here
- template: templates/bicep.yml
parameters:
environment: dev
dependsOn: GetLastCommitId
lastCommitId: $[stageDependencies.GetLastCommitId.lastCommitId.outputs['a.commitId']]
Error: syntax error: invalid arithmetic operator (error token is ".GetLastCommitId.lastCommitId.outputs['a.commitId']
syntax according to microsoft doc: $[stageDependencies.A.A1.outputs['MyOutputVar.myStageVal']]
Here is documentation from Microsoft: https://learn.microsoft.com/en-us/azure/devops/pipelines/process/set-variables-scripts?view=azure-devops&tabs=bash

Answer 1

The value of the parameter your are trying to set is done before the actually run of the tasks. Hence, the lastCommitId is not set as the value and is resulting in your different approaches into a dissapointed result.
But, depending on what is in your bicep.yml, there is a solution!
With the azure-pipeline.yml and bicep.yml below, you are able to use your lastCommitId in the template:
trigger:
- main
pool:
vmImage: ubuntu-latest
resources:
repositories:
- repository: repoName
type: git
name: projectName/repoName
ref: branchName
stages:
- stage: GetLastCommitId
jobs:
- job: lastCommitId
steps:
- checkout: repoName
- bash: |
cd repoName
echo "##vso[task.setvariable variable=commitId;isOutput=true]$(git rev-parse HEAD)"
name: a
- bash: |
echo $(a.commitId)
- checkout: self
- template: templates/bicep.yml
And the bicep.yml:
stages:
- stage: Template
jobs:
- job: JobInTemplate
variables:
lastCommitId: $[stageDependencies.GetLastCommitId.lastCommitId.outputs['a.commitId']]
steps:
- script: echo the value is $(lastCommitId)