Added initial implementation to detect changes

internal/pkg/controller/controller.go

@@ -0,0 +1,373 @@
+package controller
+
+import (
+	"bytes"
+	"strings"
+	"time"
+	"fmt"
+
+	"github.com/stakater/Reloader/internal/pkg/actions"
+	"github.com/golang/glog"
+	"github.com/pkg/errors"
+
+	"k8s.io/kubernetes/pkg/api"
+
+	clientset "k8s.io/client-go/kubernetes"
+	informerruntime "k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/fields"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/watch"
+	"k8s.io/apimachinery/pkg/util/wait"
+	errorHandler "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/util/workqueue"
+
+	"sort"
+)
+
+const (
+	updateOnChangeAnnotation = "configmap.fabric8.io/update-on-change"
+	// AllNamespaces as our controller will be looking for events in all namespaces
+	AllNamespaces = ""
+)
+
+// Event indicate the informerEvent
+type Event struct {
+	key          string
+	eventType    string
+	namespace    string
+	resourceType string
+}
+
+// Controller for checking events
+type Controller struct {
+	clientset        clientset.Interface
+	indexer          cache.Indexer
+	queue            workqueue.RateLimitingInterface
+	informer         cache.Controller
+	controllerConfig config.Controller
+	Actions          []actions.Action
+
+	stopCh chan struct{}
+}
+
+// NewController for initializing a Controller
+func NewController(
+	clientset clientset.Interface,
+	resyncPeriod time.Duration, controllerConfig config.Controller, objType informerruntime.Object) (*Controller, error) {
+
+	c := Controller{
+		clientset:        clientset,
+		controllerConfig: controllerConfig,
+		stopCh: make(chan struct{}),
+	}
+
+	queue := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter())
+	listWatcher := cache.NewListWatchFromClient(clientset.CoreV1().RESTClient(), controllerConfig.Type, AllNamespaces, fields.Everything())
+
+	indexer, informer := cache.NewIndexerInformer(listWatcher, objType, 0, cache.ResourceEventHandlerFuncs {
+		AddFunc:    c.Add,
+		UpdateFunc: c.Update,
+		DeleteFunc: c.Delete,
+	}, cache.Indexers{})
+
+	/*c.cmLister.Store, c.cmController = framework.NewInformer(
+		&cache.ListWatch{
+			ListFunc:  configMapListFunc(c.client, namespace),
+			WatchFunc: configMapWatchFunc(c.client, namespace),
+		},
+		&api.ConfigMap{},
+		resyncPeriod,
+		framework.ResourceEventHandlerFuncs{
+			AddFunc: func(obj interface{}) {
+				newCM := obj.(*api.ConfigMap)
+				//typeOfMaster, err := util.TypeOfMaster(kubeClient)
+				if err != nil {
+					glog.Fatalf("failed to create REST client config: %s", err)
+				}
+				err = rollingUpgradeDeployments(newCM, kubeClient)
+				if err != nil {
+					glog.Errorf("failed to update Deployment: %v", err)
+				}
+
+			},
+			UpdateFunc: func(oldObj interface{}, newObj interface{}) {
+				oldM := oldObj.(*api.ConfigMap)
+				newCM := newObj.(*api.ConfigMap)
+
+				if oldM.ResourceVersion != newCM.ResourceVersion {
+					//typeOfMaster, err := util.TypeOfMaster(kubeClient)
+					if err != nil {
+						glog.Fatalf("failed to create REST client config: %s", err)
+					}
+					err = rollingUpgradeDeployments(newCM, kubeClient)
+					if err != nil {
+						glog.Errorf("failed to update Deployment: %v", err)
+					}
+				}
+			},
+		},
+	)*/
+	return &c, nil
+}
+
+// Run starts the controller.
+/*func (c *Controller) Run() {
+	glog.Infof("starting reloader")
+
+	<-c.stopCh
+}*/
+
+// Stop stops the controller.
+/*func (c *Controller) Stop() {
+	glog.Infof("stopping reloader")
+
+	close(c.stopCh)
+}*/
+
+// Add function to add a 'create' event to the queue in case of creating a pod
+func (c *Controller) Add(obj interface{}) {
+	key, err := cache.MetaNamespaceKeyFunc(obj)
+	var event Event
+
+	if err == nil {
+		event.key = key
+		event.eventType = "create"
+		c.queue.Add(event)
+	}
+}
+
+// Update function to add an 'update' event to the queue in case of updating a pod
+func (c *Controller) Update(old interface{}, new interface{}) {
+	key, err := cache.MetaNamespaceKeyFunc(new)
+	var event Event
+
+	if err == nil {
+		c.queue.Add(event)
+	}
+}
+
+// Delete function to add a 'delete' event to the queue in case of deleting a pod
+func (c *Controller) Delete(obj interface{}) {
+	//In current scenario, we dont need to do anything when a pod is deleted so it is empty now
+}
+
+//Run function for controller which handles the queue
+func (c *Controller) Run(threadiness int, stopCh chan struct{}) {
+
+	glog.Infof("Starting Controller for type ", c.controllerConfig.Type)
+	defer errorHandler.HandleCrash()
+
+	// Let the workers stop when we are done
+	defer c.queue.ShutDown()
+
+	go c.informer.Run(stopCh)
+
+	// Wait for all involved caches to be synced, before processing items from the queue is started
+	if !cache.WaitForCacheSync(stopCh, c.informer.HasSynced) {
+		errorHandler.HandleError(fmt.Errorf("Timed out waiting for caches to sync"))
+		return
+	}
+
+	for i := 0; i < threadiness; i++ {
+		go wait.Until(c.runWorker, time.Second, stopCh)
+	}
+
+	<-stopCh
+	glog.Infof("Stopping Controller for type ", c.controllerConfig.Type)
+}
+
+func (c *Controller) runWorker() {
+	for c.processNextItem() {
+	}
+}
+
+func (c *Controller) processNextItem() bool {
+	// Wait until there is a new item in the working queue
+	event, quit := c.queue.Get()
+	if quit {
+		return false
+	}
+	// Tell the queue that we are done with processing this key. This unblocks the key for other workers
+	// This allows safe parallel processing because two events with the same key are never processed in
+	// parallel.
+	defer c.queue.Done(event)
+
+	// Invoke the method containing the business logic
+	err := c.takeAction(event.(Event))
+	// Handle the error if something went wrong during the execution of the business logic
+	c.handleErr(err, event)
+	return true
+}
+
+// main business logic that acts bassed on the event or key
+func (c *Controller) takeAction(event Event) error {
+
+	obj, _, err := c.indexer.GetByKey(event.key)
+	if err != nil {
+		glog.Infof("Fetching object with key %s from store failed with %v", event.key, err)
+	}
+	if obj == nil {
+		glog.Infof("Error in Action")
+	} else {
+		glog.Infof("Detected changes in object %s", obj)
+		/*glog.Infof("Resource block not found, performing actions")
+		// process events based on its type
+		for index, action := range c.Actions {
+			glog.Infof("Performing '%s' action for controller of type '%s'", c.controllerConfig.Actions[index].Name, c.controllerConfig.Type)
+			switch event.eventType {
+			case "create":
+				action.ObjectCreated(obj)
+			case "update":
+				//TODO: Figure how to pass old and new object
+				action.ObjectUpdated(obj, nil)
+			case "delete":
+				action.ObjectDeleted(obj)
+			}
+		}*/
+	}
+	return nil
+}
+
+// handleErr checks if an error happened and makes sure we will retry later.
+func (c *Controller) handleErr(err error, key interface{}) {
+	if err == nil {
+		// Forget about the #AddRateLimited history of the key on every successful synchronization.
+		// This ensures that future processing of updates for this key is not delayed because of
+		// an outdated error history.
+		c.queue.Forget(key)
+		return
+	}
+
+	// This controller retries 5 times if something goes wrong. After that, it stops trying.
+	if c.queue.NumRequeues(key) < 5 {
+		log.Printf("Error syncing events %v: %v", key, err)
+
+		// Re-enqueue the key rate limited. Based on the rate limiter on the
+		// queue and the re-enqueue history, the key will be processed later again.
+		c.queue.AddRateLimited(key)
+		return
+	}
+
+	c.queue.Forget(key)
+	// Report to an external entity that, even after several retries, we could not successfully process this key
+	runtime.HandleError(err)
+	log.Printf("Dropping the key %q out of the queue: %v", key, err)
+}
+
+/*func configMapListFunc(c *client.Client, ns string) func(api.ListOptions) (runtime.Object, error) {
+	return func(opts api.ListOptions) (runtime.Object, error) {
+		return c.ConfigMaps(ns).List(opts)
+	}
+}
+
+func configMapWatchFunc(c *client.Client, ns string) func(options api.ListOptions) (watch.Interface, error) {
+	return func(options api.ListOptions) (watch.Interface, error) {
+		return c.ConfigMaps(ns).Watch(options)
+	}
+}
+
+func rollingUpgradeDeployments(cm *api.ConfigMap, c *client.Client) error {
+	ns := cm.Namespace
+	configMapName := cm.Name
+	configMapVersion := convertConfigMapToToken(cm)
+
+	deployments, err := c.Deployments(ns).List(api.ListOptions{})
+	if err != nil {
+		return errors.Wrap(err, "failed to list deployments")
+	}
+	for _, d := range deployments.Items {
+		containers := d.Spec.Template.Spec.Containers
+		// match deployments with the correct annotation
+		annotationValue, _ := d.ObjectMeta.Annotations[updateOnChangeAnnotation]
+		if annotationValue != "" {
+			values := strings.Split(annotationValue, ",")
+			matches := false
+			for _, value := range values {
+				if value == configMapName {
+					matches = true
+					break
+				}
+			}
+			if matches {
+				updateContainers(containers, annotationValue, configMapVersion)
+
+				// update the deployment
+				_, err := c.Deployments(ns).Update(&d)
+				if err != nil {
+					return errors.Wrap(err, "update deployment failed")
+				}
+				glog.Infof("Updated Deployment %s", d.Name)
+			}
+		}
+	}
+	return nil
+}*/
+
+// lets convert the configmap into a unique token based on the data values
+func convertConfigMapToToken(cm *api.ConfigMap) string {
+	values := []string{}
+	for k, v := range cm.Data {
+		values = append(values, k+"="+v)
+	}
+	sort.Strings(values)
+	text := strings.Join(values, ";")
+	// we could zip and base64 encode
+	// but for now we could leave this easy to read so that its easier to diagnose when & why things changed
+	return text
+}
+
+func updateContainers(containers []api.Container, annotationValue, configMapVersion string) bool {
+	// we can have multiple configmaps to update
+	answer := false
+	configmaps := strings.Split(annotationValue, ",")
+	for _, cmNameToUpdate := range configmaps {
+		configmapEnvar := "FABRIC8_" + convertToEnvVarName(cmNameToUpdate) + "_CONFIGMAP"
+
+		for i := range containers {
+			envs := containers[i].Env
+			matched := false
+			for j := range envs {
+				if envs[j].Name == configmapEnvar {
+					matched = true
+					if envs[j].Value != configMapVersion {
+						glog.Infof("Updating %s to %s", configmapEnvar, configMapVersion)
+						envs[j].Value = configMapVersion
+						answer = true
+					}
+				}
+			}
+			// if no existing env var exists lets create one
+			if !matched {
+				e := api.EnvVar{
+					Name:  configmapEnvar,
+					Value: configMapVersion,
+				}
+				containers[i].Env = append(containers[i].Env, e)
+				answer = true
+			}
+		}
+	}
+	return answer
+}
+
+// convertToEnvVarName converts the given text into a usable env var
+// removing any special chars with '_'
+func convertToEnvVarName(text string) string {
+	var buffer bytes.Buffer
+	lower := strings.ToUpper(text)
+	lastCharValid := false
+	for i := 0; i < len(lower); i++ {
+		ch := lower[i]
+		if (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9') {
+			buffer.WriteString(string(ch))
+			lastCharValid = true
+		} else {
+			if lastCharValid {
+				buffer.WriteString("_")
+			}
+			lastCharValid = false
+		}
+	}
+	return buffer.String()
+}