[Bug]: ServerlessCache Update Fails When Modifying Multiple Fields

[vargaadam]

Is there an existing issue for this?

• I have searched the existing issues

Affected Resource(s)

elasticache.aws.upbound.io/v1beta1 - ServerlessCache

Resource MRs required to reproduce the bug

apiVersion: elasticache.aws.upbound.io/v1beta1
kind: ServerlessCache
metadata:
  name: example-serverless-cache
spec:
  deletionPolicy: Delete
  forProvider:
    cacheUsageLimits:
      - dataStorage:
          - maximum: 10
            unit: GB
        ecpuPerSecond:
          - maximum: 5000
    dailySnapshotTime: '1:00'
    description: ' '
    engine: redis
    majorEngineVersion: '7'
    region: region
    securityGroupIdRefs:
      - name: example-cache-elasticache-sg
    securityGroupIds:
      - example-security-group-id
    snapshotRetentionLimit: 5
    subnetIdRefs:
      - name: example-private-a
      - name: example-private-b
    subnetIdSelector:
      matchLabels:
        example.com/environment: environment
        example.com/project: project
    subnetIds:
      - subnet-1
      - subnet-2
    tags:
      crossplane-kind: serverlesscache.elasticache.aws.upbound.io
      crossplane-providerconfig: aws-provider
    userGroupId: user-group-id
  initProvider: {}
  managementPolicies:
    - '*'
  providerConfigRef:
    name: provider-config-ref

Steps to Reproduce

1. Apply the above ServerlessCache manifest to your environment.
2. Modify two parameters simultaneously in the ServerlessCache resource. For example, update cacheUsageLimits and dailySnapshotTime.
3. Apply the updated manifest.

What happened?

When attempting to apply a manifest with changes to multiple parameters, the operation fails with an error.

The ServerlessCache resource controller should:

1. Detect that multiple fields have been updated in the manifest.
2. Sequentially execute multiple API requests to update one field at a time, respecting the limitation of the ModifyServerlessCache API.
3. Return a success status after all updates have been successfully applied.

Relevant Error Output Snippet

update failed: async update failed: resource update call returned error diags: updating ElastiCache Serverless Cache (redacted): operation error ElastiCache: ModifyServerlessCache, https response error StatusCode: 400, RequestID: redacted, InvalidParameterCombination: Serverless Cache modifications only support modifying one field per request.

Crossplane Version

v1.17.0

Provider Version

v1.17.0

Kubernetes Version

v1.31.2-eks-7f9249a

Kubernetes Distribution

EKS

Additional Info

No response

[mergenci]

I agree that the declarative API should handle imperative operations as needed. However, doing so doesn't seem feasible, given the status quo. We rely on the underlying Terraform provider's functionality. If it doesn't handle the case where there are multiple field updates, we have to implement the logic at the Crossplane provider level — in Upjet to be specific. Unless such a functionality would help many resources, or very common use cases, I don't think it would be worth the effort to implement it.