K8S Config Connector

Skill: Match Mock behaviour with real GCP api

This skill provides a structured workflow for matching the mock {service}{resource} behaviour with the real GCP.

When the golden tests for K8s Config Connector mock output diverge from real GCP output, we need to inspect the discrepancies and fix either the mock implementation or the normalizers. This ensures that hack/compare-mock runs cleanly and accurately represents GCP API contracts.

Critical Rules

• Real GCP Baseline Required: You must always generate the initial baseline _http.log by running hack/record-gcp against a real GCP project and commit it first.
• Do NOT Generate Golden Logs from Mock: You are strictly forbidden from generating or updating _http.log files against the mock in this step. You MUST first establish a baseline against real GCP with E2E_GCP_TARGET=real E2E_KUBE_TARGET=envtest with WRITE_GOLDEN_OUTPUT=1.

Workflow

Step 1: Record GCP logs

1. Run hack/record-gcp "fixtures/^<testname>$" to capture real GCP behavior.
   • Troubleshooting Service Not Enabled: If hack/record-gcp fails because a GCP service is not enabled (e.g., error mentions that the API is disabled or has not been used in the project before), enable the service using gcloud and try again:

     gcloud services enable <service-name>.googleapis.com
     

     (For example: gcloud services enable compute.googleapis.com or gcloud services enable run.googleapis.com)
2. Please commit the real gcp logs generated by running the command.

Important:

• It is important to commit the files modified by running realgcp tests in its own commit.
• This is for the human reviewer to compare the diff in the test artifacts when running real and mockgcp.

Step 2: Match mockgcp behaviour with real GCP

1. Run hack/compare-mock "fixtures/^<testname>$" to check mock behavior.
2. Iteratively fix discrepancies in the mock implementation or normalize.go.

Tips for fixing the discrepancies:

1. Look closely at the compare-mock HTTP log differences (typically mock on left => real on right).
2. For missing default values (e.g., <missing> => REGIONAL), add a populateDefaultsFor<Resource> function to the mock service's file (e.g. mockgcp/mockcompute/networksv1.go). Make sure it is called on Insert and Get.
3. For generated IDs or volatile values (e.g. IPs, resource URLs) where real GCP generates dynamically but mockgcp outputs something static, you need to update the normalizer mockgcp/mock<service>/normalize.go.
4. Run hack/compare-mock "fixtures/^<testname>$" to see the diff and overwrite _http.log.
5. Run git diff on the test fixtures to ensure that the golden _http.log accurately replaces volatile data with placeholder variables (e.g., ${ipAddress}).
6. Certain operation metadata values (e.g. done: <missing> => false) can be safely ignored as mock operations are generally simpler.

Source: GoogleCloudPlatform/k8s-config-connector — distributed by TomeVault.