statefulset-primitive

StatefulSet Primitive Example

This example demonstrates the usage of the statefulset primitive within the operator component framework. It shows how to manage a Kubernetes StatefulSet as a component of a larger application, utilizing features like:

• Base Construction: Initializing a StatefulSet with basic metadata, spec, and volume claim templates.
• Feature Mutations: Applying version-gated or conditional changes (sidecars, env vars, annotations) using the Mutator.
• Custom Status Handlers: Overriding the default logic for determining readiness (via ConvergingStatus and the WithCustomConvergeStatus builder hook) and health assessment during rollouts (GraceStatus).
• Custom Suspension: Extending the default suspension logic (scaling to 0) with additional mutations.
• Data Extraction: Harvesting information from the reconciled resource.

Directory Structure

• app/: Defines the mock ExampleApp CRD and the controller that uses the component framework.
• features/: Contains modular feature definitions:
  • mutations.go: sidecar injection, env vars, and version-based image updates.
  • handlers.go: custom status and suspension handlers.
• resources/: Contains the central NewStatefulSetResource factory that assembles all features using the statefulset.Builder.
• main.go: A standalone entry point that demonstrates a single reconciliation loop using a fake client.

Running the Example

You can run this example directly using go run:

go run examples/statefulset-primitive/main.go

This will:

1. Initialize a fake Kubernetes client.
2. Create an ExampleApp owner object.
3. Reconcile the ExampleApp components.
4. Print the resulting status conditions.