Patching a resource from a value obtained from function-go-templating

[ashishkurian]

Hi Folks,

I want to patch a resource inside the function-patch-and-transform function using a value that I obtain from the function-go-templating.

I see the other way where we get data from the go template function into the p&t function here

I am attaching my sample composition below.

---
# Removed for brevity
  pipeline:
    - step: castai-ekscluster
      functionRef:
        name: function-go-templating
      input:
        apiVersion: gotemplating.fn.crossplane.io/v1beta1
        kind: GoTemplate
        source: Inline
        inline:
          template: |
            {{- $environmentConfigs := (index .context "apiextensions.crossplane.io/environment") }}
            {{- $accountIdstr := printf "%q" (index $environmentConfigs "accountId") }}
            {{- $eksClusterName := printf "%q" (index $environmentConfigs "eksClusterName") }}
            {{- $region := (index $environmentConfigs "region") }}
            {{- $deletionPolicy := .observed.composite.resource.spec.crossplaneParameters.deletionPolicy }}
            {{- $providerConfigRef := "default" }}
            ---
            apiVersion: castai.upbound.io/v1alpha1
            kind: EksClusterId
            metadata:
              annotations:
                gotemplating.fn.crossplane.io/composition-resource-name: EksClusterId
              labels:
                cast-ai-cluster: {{$eksClusterName}}
            spec:
              deletionPolicy: {{$deletionPolicy}}
              providerConfigRef:
                name: {{$providerConfigRef}}
              forProvider:
                region: {{$region}}
                accountId: {{$accountIdstr}}
                clusterName: {{$eksClusterName}}
    
    
    - step: aws-auth-patch
      functionRef:
        name: function-patch-and-transform
      input:
        apiVersion: pt.fn.crossplane.io/v1beta1
        kind: Resources
        resources:
          - name: awsauthconfigmap
            base:
              apiVersion: v1
              kind: ConfigMap
              metadata:
                name: ashish-test
                namespace: castai-agent
            patches:
              - type: FromCompositeFieldPath
                fromFieldPath: HERE I want the value from the function-go-templating
                toFieldPath: "data.mapRoles"
                transforms:
                  - type: string
                    string:
                      type: Format
                      fmt: '[{"rolearn": "%s", "username": "system:node:{{EC2PrivateDNSName}}", "groups": ["system:masters"]}]'

tagging @ytsarev as you might already be knowing solution.

[phisco]

You mean some value from the status of the EksClusterId resource created from function-go-templating?

Unfortunately f-go-templating can't write to the environment, so you'd have to define an empty resource in f-p-and-t, patch from that to the environment and then from the environment to your configmap. But why not just access the observed resource in function-go-templating?

[ashishkurian]

@phisco Can please you show that here in my example on how to access the observed resource value into the p&t function?

When I used .observed.... I got some erros. I am not at my laptop and thus could not share the exact error.