source

Documentation

Overview

Package source provides event streams to hook up to Controllers with Controller.Watch. Events are used with handler.EventHandlers to enqueue reconcile.Requests and trigger Reconciles for Kubernetes objects.

Index

• type ChannelOpt
  • func WithBufferSize[T any](bufferSize int) ChannelOpt[T]
  • func WithPredicates[T any](p ...predicate.TypedPredicate[T]) ChannelOpt[T]
• type Func
  • func (f Func) Start(ctx context.Context, queue workqueue.RateLimitingInterface) error
  • func (f Func) String() string
• type Informer
  • func (is *Informer) Start(ctx context.Context, queue workqueue.RateLimitingInterface) error
  • func (is *Informer) String() string
• type Source
  • func Channel[T any](source <-chan event.TypedGenericEvent[T], handler handler.TypedEventHandler[T], ...) Source
• type SyncingSource
  • func Kind[T client.Object](cache cache.Cache, object T, handler handler.TypedEventHandler[T], ...) SyncingSource

Examples

• Channel
• Kind

Types

type ChannelOpt

type ChannelOpt[T any] func(*channel[T])

ChannelOpt allows to configure a source.Channel.

func WithBufferSize

func WithBufferSize[T any](bufferSize int) ChannelOpt[T]

WithBufferSize configures the buffer size for a source.Channel. By default, the buffer size is 1024.

func WithPredicates

func WithPredicates[T any](p ...predicate.TypedPredicate[T]) ChannelOpt[T]

WithPredicates adds the configured predicates to a source.Channel.

type Func

type Func func(context.Context, workqueue.RateLimitingInterface) error

Func is a function that implements Source.

func (Func) Start

func (f Func) Start(ctx context.Context, queue workqueue.RateLimitingInterface) error

Start implements Source.

func (Func) String

func (f Func) String() string

type Informer

type Informer struct {
	// Informer is the controller-runtime Informer
	Informer   cache.Informer
	Handler    handler.EventHandler
	Predicates []predicate.Predicate
}

Informer is used to provide a source of events originating inside the cluster from Watches (e.g. Pod Create).

func (*Informer) Start

func (is *Informer) Start(ctx context.Context, queue workqueue.RateLimitingInterface) error

Start is internal and should be called only by the Controller to register an EventHandler with the Informer to enqueue reconcile.Requests.

func (*Informer) String

func (is *Informer) String() string

type Source

type Source interface {
	// Start is internal and should be called only by the Controller to register an EventHandler with the Informer
	// to enqueue reconcile.Requests.
	Start(context.Context, workqueue.RateLimitingInterface) error
}

Source is a source of events (e.g. Create, Update, Delete operations on Kubernetes Objects, Webhook callbacks, etc) which should be processed by event.EventHandlers to enqueue reconcile.Requests.

* Use Kind for events originating in the cluster (e.g. Pod Create, Pod Update, Deployment Update).

* Use Channel for events originating outside the cluster (e.g. GitHub Webhook callback, Polling external urls).

Users may build their own Source implementations.

func Channel

func Channel[T any](source <-chan event.TypedGenericEvent[T], handler handler.TypedEventHandler[T], opts ...ChannelOpt[T]) Source

Channel is used to provide a source of events originating outside the cluster (e.g. GitHub Webhook callback). Channel requires the user to wire the external source (e.g. http handler) to write GenericEvents to the underlying channel.

Example

This example reads GenericEvents from a channel and enqueues a reconcile.Request containing the Name and Namespace provided by the event.

package main

import (
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/event"
	"sigs.k8s.io/controller-runtime/pkg/handler"
	"sigs.k8s.io/controller-runtime/pkg/source"
)

var ctrl controller.Controller

func main() {
	events := make(chan event.GenericEvent)

	err := ctrl.Watch(
		source.Channel(
			events,
			&handler.EnqueueRequestForObject{},
		),
	)
	if err != nil {
		// handle it
	}
}

type SyncingSource

type SyncingSource interface {
	Source
	WaitForSync(ctx context.Context) error
}

SyncingSource is a source that needs syncing prior to being usable. The controller will call its WaitForSync prior to starting workers.

func Kind

func Kind[T client.Object](cache cache.Cache, object T, handler handler.TypedEventHandler[T], predicates ...predicate.TypedPredicate[T]) SyncingSource

Kind creates a KindSource with the given cache provider.

Example

This example Watches for Pod Events (e.g. Create / Update / Delete) and enqueues a reconcile.Request with the Name and Namespace of the Pod.

package main

import (
	corev1 "k8s.io/api/core/v1"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/handler"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/source"
)

var mgr manager.Manager
var ctrl controller.Controller

func main() {
	err := ctrl.Watch(source.Kind(mgr.GetCache(), &corev1.Pod{}, &handler.TypedEnqueueRequestForObject[*corev1.Pod]{}))
	if err != nil {
		// handle it
	}
}