Azure Pipelines - setting a stage variable from another stage's output
I just can't stop stumbling on the difference between Azure Pipelines runtime ($[]) and compile time expressions (${{ }}). This bit me again when trying to set up a seemingly simple stage - stage dependency with conditions
The docs say that dependencies between stages should be done using the dependencies.STAGE.outputs['JOB.STEP.VARIABLE'] syntax. And fair enough, this works for conditions.
What it does not work for is variables. In order to set a variable from another stage's output, use $[ stageDependencies.STAGE.JOB.outputs['STEP.VARIABLE'] ]
This does not work:
- stage: Debug
dependsOn: DETERMINE_CHANGES
condition: or(eq(dependencies.DETERMINE_CHANGES.outputs['backend.hasChanges.result'], 'true'), eq(${{ parameters.forceDeploy }}, true))
variables:
backend_changes: $[ dependencies.DETERMINE_CHANGES.outputs['backend.hasChanges.result'] ]
jobs:
- job: PrintVariables
steps:
- bash: |
echo "Backend changes detected: $(backend_changes)"
name: debugStep
This does:
- stage: Debug
dependsOn: DETERMINE_CHANGES
condition: or(eq(dependencies.DETERMINE_CHANGES.outputs['backend.hasChanges.result'], 'true'), eq(${{ parameters.forceDeploy }}, true))
variables:
backend_changes: $[ stageDependencies.DETERMINE_CHANGES.backend.outputs['hasChanges.result'] ]
jobs:
- job: PrintVariables
steps:
- bash: |
echo "Backend changes detected: $(backend_changes)"
name: debugStep
So even though we're seemingly reading the same variable in the same place, the syntax is different. What fun.
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