custom-resource

Custom Resource

This example demonstrates how to manage a custom resource (CRD) that has no typed primitive in the framework, using the unstructured static builder.

What it shows

• Unstructured builder: unstructured/static.NewBuilder wraps an *unstructured.Unstructured object, giving it the same mutation and extraction capabilities as any typed primitive.
• Content mutations: EditContent with UnstructuredContentEditor sets nested spec fields (issuerRef, dnsNames) using structured helpers rather than raw map manipulation.
• Metadata mutations: EditObjectMetadata works the same way as on typed primitives.
• Declared extraction: static.ExtractInto reads fields from the reconciled unstructured object into a data cell.
• Resource metrics: metrics.NewRecorder records condition metrics and per-resource apply counters, and WithMetricsIdentifier keys the counters by a constant instead of the object's per-owner name.

Use case

When your operator needs to manage a third-party CRD (cert-manager Certificate, Istio VirtualService, etc.) that has no typed primitive wrapper in the framework, the unstructured builder is the escape hatch. You get the same reconciliation, mutation, and extraction patterns without writing a full typed primitive.

Reconciliation steps

1. Create the CertificateRequest with DNS names and issuer reference.
2. Steady-state reconciliation.
3. Print the apply counters gathered from the registry.

Metrics

The CertificateRequest is named <owner>-cert, so keying a metric by its name would create one time series per ExampleApp, and the framework never removes a series once created. WithMetricsIdentifier("certificate") keys it by a constant instead, and the series count stays fixed however many owners exist.

The run ends by printing what the two reconciles did:

ocf_resource_apply_total{...,operation="created",resource="certificate"} 1
ocf_resource_apply_total{...,operation="none",resource="certificate"} 1

One create, then nothing to do. A resource whose operation="updated" count keeps climbing in steady state is being rewritten on every reconcile even though nothing changed. See Metrics.

Running

go run ./examples/custom-resource/.