/
controller.go
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/
controller.go
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package main
import (
"context"
"fmt"
"os"
"time"
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/util/wait"
coreinformers "k8s.io/client-go/informers/core/v1"
"k8s.io/client-go/kubernetes"
corelister "k8s.io/client-go/listers/core/v1"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/util/workqueue"
"k8s.io/klog"
)
type Controller struct {
clientset kubernetes.Interface
nodeLister corelister.NodeLister
nodesSynced cache.InformerSynced
workqueue workqueue.RateLimitingInterface
}
func newController(clientset kubernetes.Interface, nodeInformer coreinformers.NodeInformer) *Controller {
controller := &Controller{
clientset: clientset,
nodeLister: nodeInformer.Lister(),
nodesSynced: nodeInformer.Informer().HasSynced,
workqueue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), controllerAgentName),
}
// register event handlers to fill the queue with nodes creations, updates and deletions
nodeInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
klog.Info("Add event handler called")
key, err := cache.MetaNamespaceKeyFunc(obj)
if err == nil {
controller.workqueue.Add(key)
}
},
UpdateFunc: func(old interface{}, new interface{}) {
klog.Info("Update event handler called")
key, err := cache.MetaNamespaceKeyFunc(new)
if err == nil {
controller.workqueue.Add(key)
}
},
DeleteFunc: func(obj interface{}) {
// IndexerInformer uses a delta nodeQueue, therefore for deletes we have to use this
// key function.
klog.Info("Delete event handler called")
key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(obj)
if err == nil {
controller.workqueue.Add(key)
}
},
},
)
return controller
}
func (c *Controller) Run(threadiness int, stopCh <-chan struct{}) error {
defer runtime.HandleCrash()
// make sure the work queue is shutdown which will trigger workers to end
defer c.workqueue.ShutDown()
// Start the informer factories to begin populating the informer caches
klog.Infof("Starting %s controller", controllerAgentName)
// Wait for the caches to be synced before starting workers
klog.Info("Waiting for informer caches to sync")
if ok := cache.WaitForCacheSync(stopCh, c.nodesSynced); !ok {
return fmt.Errorf("failed to wait for caches to sync")
}
// start up your worker threads based on threadiness. Some controllers
// have multiple kinds of workers
klog.Info("Starting workers")
for i := 0; i < threadiness; i++ {
// runWorker will loop until "something bad" happens. The .Until will
// then rekick the worker after one second
go wait.Until(c.runWorker, time.Second, stopCh)
}
klog.Info("Started workers")
// wait until we're told to stop
<-stopCh
klog.Info("Shutting down workers")
return nil
}
// runWorker function operate on the queue and process each item
func (c *Controller) runWorker() {
// hot loop until we're told to stop. processNextWorkItem will
// automatically wait until there's work available, so we don't worry
// about secondary waits
for c.processNextWorkItem() {
}
}
// processNextWorkItem deals with one key off the queue. It returns false
// when it's time to quit.
func (c *Controller) processNextWorkItem() bool {
obj, shutdown := c.workqueue.Get()
if shutdown {
return false
}
// We wrap this block in a func so we can defer c.workqueue.Done.
err := func(obj interface{}) error {
// We call Done here so the workqueue knows we have finished
// processing this item. We also must remember to call Forget if we
// do not want this work item being re-queued. For example, we do
// not call Forget if a transient error occurs, instead the item is
// put back on the workqueue and attempted again after a back-off
// period.
defer c.workqueue.Done(obj)
var key string
var ok bool
// We expect strings to come off the workqueue. These are of the
// form namespace/name. We do this as the delayed nature of the
// workqueue means the items in the informer cache may actually be
// more up to date that when the item was initially put onto the
// workqueue.
if key, ok = obj.(string); !ok {
// As the item in the workqueue is actually invalid, we call
// Forget here else we'd go into a loop of attempting to
// process a work item that is invalid.
c.workqueue.Forget(obj)
runtime.HandleError(fmt.Errorf("expected string in workqueue but got %#v", obj))
return nil
}
// Run the syncHandler, passing it the namespace/name string of the
// Foo resource to be synced.
if err := c.syncHandler(key); err != nil {
// Put the item back on the workqueue to handle any transient errors.
c.workqueue.AddRateLimited(key)
return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
}
// Finally, if no error occurs we Forget this item so it does not
// get queued again until another change happens.
c.workqueue.Forget(obj)
klog.Infof("Successfully synced '%s'", key)
return nil
}(obj)
if err != nil {
runtime.HandleError(err)
return true
}
return true
}
// syncHandler compares the actual state with the desired, and attempts to
// converge the two.
func (c *Controller) syncHandler(key string) error {
// Convert the namespace/name string into a distinct namespace and name
_, name, err := cache.SplitMetaNamespaceKey(key)
if err != nil {
runtime.HandleError(fmt.Errorf("invalid resource key: %s", key))
return nil
}
// Get the Node resource with this namespace/name
node, err := c.nodeLister.Get(name)
if err != nil {
// The node resource may no longer exist, in which case we stop
// processing.
if errors.IsNotFound(err) {
runtime.HandleError(fmt.Errorf("node '%s' in work queue no longer exists", key))
return nil
}
return err
}
if !validateNodeOS(node.Status.NodeInfo.OperatingSystem) {
klog.Info("Node is not of OS that is specified in the command line argument")
return nil
}
err = c.updateNodeLabel(node, node.Status.NodeInfo.OperatingSystem)
if err != nil {
fmt.Printf("\nError updating the node %s", err.Error())
return err
}
return nil
}
func validateNodeOS(nodeos string) bool {
osName := os.Args[1]
klog.Infof("the required OS for node is: %s", osName)
//if the user did not provide arguments to the command. use client-go to get the nodes and prompt the user to select.
//then return the node to exec function.
return osName == nodeos
}
// UPdate the node label
func (c *Controller) updateNodeLabel(node *v1.Node, nodeos string) error {
// NEVER modify objects from the store. It's a read-only, local cache.
// You can use DeepCopy() to make a deep copy of original object and modify this copy
// Or create a copy manually for better performance
nodeCopy := node.DeepCopy()
nodeCopy.Labels["k8c.io/uses-"+nodeos] = "true"
_, err := c.clientset.CoreV1().Nodes().Update(context.Background(), nodeCopy, metav1.UpdateOptions{})
return err
}