controller-runtime: sigs.k8s.io/controller-runtime/pkg/controller Index | Examples | Files | Directories

package controller

import "sigs.k8s.io/controller-runtime/pkg/controller"

Package controller provides types and functions for building Controllers. Controllers implement Kubernetes APIs.

Creation

To create a new Controller, first create a manager.Manager and pass it to the controller.New function. The Controller MUST be started by calling Manager.Start.

Index

Examples

Package Files

controller.go doc.go

type Controller Uses

type Controller interface {
    // Reconciler is called to reconcile an object by Namespace/Name
    reconcile.Reconciler

    // Watch takes events provided by a Source and uses the EventHandler to
    // enqueue reconcile.Requests in response to the events.
    //
    // Watch may be provided one or more Predicates to filter events before
    // they are given to the EventHandler.  Events will be passed to the
    // EventHandler if all provided Predicates evaluate to true.
    Watch(src source.Source, eventhandler handler.EventHandler, predicates ...predicate.Predicate) error

    // Start starts the controller.  Start blocks until stop is closed or a
    // controller has an error starting.
    Start(stop <-chan struct{}) error
}

Controller implements a Kubernetes API. A Controller manages a work queue fed reconcile.Requests from source.Sources. Work is performed through the reconcile.Reconciler for each enqueued item. Work typically is reads and writes Kubernetes objects to make the system state match the state specified in the object Spec.

This example starts a new Controller named "pod-controller" to Watch Pods and call a no-op Reconciler.

Code:

// mgr is a manager.Manager

// Create a new Controller that will call the provided Reconciler function in response
// to events.
c, err := controller.New("pod-controller", mgr, controller.Options{
    Reconciler: reconcile.Func(func(o reconcile.Request) (reconcile.Result, error) {
        // Your business logic to implement the API by creating, updating, deleting objects goes here.
        return reconcile.Result{}, nil
    }),
})
if err != nil {
    log.Error(err, "unable to create pod-controller")
    os.Exit(1)
}

// Watch for Pod create / update / delete events and call Reconcile
err = c.Watch(&source.Kind{Type: &corev1.Pod{}}, &handler.EnqueueRequestForObject{})
if err != nil {
    log.Error(err, "unable to watch pods")
    os.Exit(1)
}

// Start the Controller through the manager.
if err := mgr.Start(signals.SetupSignalHandler()); err != nil {
    log.Error(err, "unable to continue running manager")
    os.Exit(1)
}

This example starts a new Controller named "pod-controller" to Watch Pods with the unstructured object and call a no-op Reconciler.

Code:

// mgr is a manager.Manager

// Create a new Controller that will call the provided Reconciler function in response
// to events.
c, err := controller.New("pod-controller", mgr, controller.Options{
    Reconciler: reconcile.Func(func(o reconcile.Request) (reconcile.Result, error) {
        // Your business logic to implement the API by creating, updating, deleting objects goes here.
        return reconcile.Result{}, nil
    }),
})
if err != nil {
    log.Error(err, "unable to create pod-controller")
    os.Exit(1)
}

u := &unstructured.Unstructured{}
u.SetGroupVersionKind(schema.GroupVersionKind{
    Kind:    "Pod",
    Group:   "",
    Version: "v1",
})
// Watch for Pod create / update / delete events and call Reconcile
err = c.Watch(&source.Kind{Type: u}, &handler.EnqueueRequestForObject{})
if err != nil {
    log.Error(err, "unable to watch pods")
    os.Exit(1)
}

// Start the Controller through the manager.
if err := mgr.Start(signals.SetupSignalHandler()); err != nil {
    log.Error(err, "unable to continue running manager")
    os.Exit(1)
}

func New Uses

func New(name string, mgr manager.Manager, options Options) (Controller, error)

New returns a new Controller registered with the Manager. The Manager will ensure that shared Caches have been synced before the Controller is Started.

This example creates a new Controller named "pod-controller" with a no-op reconcile function. The manager.Manager will be used to Start the Controller, and will provide it a shared Cache and Client.

Code:

_, err := controller.New("pod-controller", mgr, controller.Options{
    Reconciler: reconcile.Func(func(o reconcile.Request) (reconcile.Result, error) {
        // Your business logic to implement the API by creating, updating, deleting objects goes here.
        return reconcile.Result{}, nil
    }),
})
if err != nil {
    log.Error(err, "unable to create pod-controller")
    os.Exit(1)
}

type Options Uses

type Options struct {
    // MaxConcurrentReconciles is the maximum number of concurrent Reconciles which can be run. Defaults to 1.
    MaxConcurrentReconciles int

    // Reconciler reconciles an object
    Reconciler reconcile.Reconciler
}

Options are the arguments for creating a new Controller

Directories

PathSynopsis
controllertestPackage controllertest contains fake informers for testing controllers When in doubt, it's almost always better to test against a real API server using envtest.Environment.
controllerutilPackage controllerutil contains utility functions for working with and implementing Controllers.

Package controller imports 8 packages (graph) and is imported by 210 packages. Updated 2019-07-09. Refresh now. Tools for package owners.