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Kubehandler

An event dispatcher for Kubernetes controllers.

Note: This is alpha software. Please use with caution.

Sample Controller

There is a sample controller available in sample-controller/. You can use that as a starting point for building a new controller.

EventHandler

Kubehandler defines a Go interface, EventHandler. Any type that implements this interface can be used to handle events.

type EventHandler interface {
	GetName() string
	GetSynced() cache.InformerSynced
	GetInformer() cache.SharedInformer
	AddFunc(ctx context.Context, namespace, name string) error
	UpdateFunc(ctx context.Context, namespace, name string) error
	DeleteFunc(ctx context.Context, namespace, name string) error
}

Each of the Add/Update/Delete Funcs receive a context and the namespace and the name of the resource that has been modified (or created or deleted). kubehandler.DefaultHandler implements a DefaultHandler that accepts all events and does nothing. In order to make use of this behaviour, you can use the bundled DefaultHandler by inheriting from it:

type DeploymentsHandler struct {
	kubehandler.DefaultHandler
}

You will need an EventLoop to consume events. You can create one like so:

	loop := kubehandler.NewEventLoop("workqueueName")

You can then register the EventHandler with the EventLoop.

	loop.Register(&DeploymentsHandler{
		DefaultHandler: kubehandler.DefaultHandler{
			Synced:   deploymentsInformer.Informer().HasSynced,
			Informer: deploymentsInformer.Informer(),
		},
	})

Finally, run the EventLoop.

	threadiness := 2
	ctx := context.Background()

	loop.Run(ctx, threadiness)

You may use the context passed in to EventLoop.Run to stop the EventLoop.

	ctx, cancelFunc := context.WithCancel(context.Background())
	loop.Run(ctx, threadiness)

	cancelFunc()

DefaultHandler

DefaultHandler provides implementations of EventHandler.

GetName() string

Returns defaultHandler.Name

GetSynced() cache.InformerSynced

Returns defaultHandler.Synced

GetInformer() cache.SharedInformer

Returns defaultHandler.Informer

The following functions are no-ops.

AddFunc(ctx context.Context, namespace, name string) error
UpdateFunc(ctx context.Context, namespace, name string) error
DeleteFunc(ctx context.Context, namespace, name string) error

Note: The current module supports Kubernetes 1.22 and above. Kubernetes 1.21 and lower compatible module can be found in branch v0.