error pre-processing promotion variable: invalid operation: - (mismatched types string and unknown)

[scott-hpe]

Possibly my second dumb thing of the day.

I have a Stage with promotionTemplate defined where my goal is to get the region value (eg us-west-2) from the shared configmap.

spec:
  promotionTemplate:
    spec:
      vars:
        - name: cluster
          value: "${{ sharedConfigMap('cluster-region-state').mira-primary }}"
      steps:
        - task:
            name: promote

Given this shared configmap, I would expect this to return a string us-west-2. from the mira-primary key.

apiVersion: v1
kind: ConfigMap
metadata:
  name: cluster-region-state
  namespace: kargo-shared-resources
data:
  mira-primary: us-west-2
  mira-secondary: us-east-2

What I see instead is the following error. What's going on here? If I switch out the sharedConfigMap() expression for a simple string of us-west-2 then the task works as expected.

failed to build step context: failed to get step config: error pre-processing promotion variable "cluster": invalid operation: - (mismatched types string and unknown) (1:46) | sharedConfigMap('cluster-region-state').mira-primary | .............................................^

[krancour]

Syntax...

The expression language's evaluator is choking on the - in mira-primary. It thinks you're trying to substract primary from mira.

I'm about 90% sure this alternative syntax works: ${{ sharedConfigMap('cluster-region-state')['mira-primary'] }}

[scott-hpe]

YES! Thank you so much. So I named my configmap keys to match my stage names thinking I would able to do:

${{ sharedConfigMap('cluster-region-state').${{ ctx.stage }} }}

However, that returns an error error pre-processing promotion variable "cluster": unexpected token Bracket("{") making me think I cannot nest these?

[krancour]

You cannot nest them, but should not need to:

${{ sharedConfigMap('cluster-region-state')[ctx.stage] }}

[scott-hpe]

Makes sense now. I’m already inside ${{ }} so it’s going to get expanded. .