Kubernetes events watcher
Kubewatcher watches the Kubernetes API for Watches that have been configured on the fission controller. It then posts that event to the function configured in the watch.
This commit is contained in:
Soam Vasani
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kubewatcher
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import (
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"bytes"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"log"
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"strings"
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"k8s.io/client-go/1.5/kubernetes"
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"k8s.io/client-go/1.5/pkg/api"
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"k8s.io/client-go/1.5/pkg/runtime"
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"k8s.io/client-go/1.5/pkg/watch"
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"github.com/platform9/fission"
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)
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type requestType int
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const (
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SYNC requestType = iota
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)
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type (
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watchSubscription struct {
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fission.Watch
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kubeWatch watch.Interface
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}
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kubeWatcherRequest struct {
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requestType
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watches []fission.Watch
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responseChannel chan *kubeWatcherResponse
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}
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kubeWatcherResponse struct {
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error
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}
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KubeWatcher struct {
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watches map[string]watchSubscription
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kubernetesClient *kubernetes.Clientset
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poster *Poster
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requestChannel chan *kubeWatcherRequest
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}
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)
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func MakeKubeWatcher(kubernetesClient *kubernetes.Clientset, poster *Poster) *KubeWatcher {
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kw := &KubeWatcher{
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watches: make(map[string]watchSubscription),
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kubernetesClient: kubernetesClient,
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poster: poster,
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requestChannel: make(chan *kubeWatcherRequest),
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}
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go kw.svc()
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return kw
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}
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func (kw *KubeWatcher) Sync(watches []fission.Watch) error {
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req := &kubeWatcherRequest{
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requestType: SYNC,
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watches: watches,
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responseChannel: make(chan *kubeWatcherResponse),
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}
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kw.requestChannel <- req
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resp := <-req.responseChannel
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return resp.error
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}
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func (kw *KubeWatcher) svc() {
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for {
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req := <-kw.requestChannel
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switch req.requestType {
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case SYNC:
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newWatchUids := make(map[string]bool)
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for _, w := range req.watches {
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newWatchUids[w.Metadata.Uid] = true
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}
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// Remove old watches
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for uid, ws := range kw.watches {
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if _, ok := newWatchUids[uid]; !ok {
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kw.removeWatch(&ws.Watch)
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}
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}
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// Add new watches
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for _, w := range req.watches {
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if _, ok := kw.watches[w.Metadata.Uid]; !ok {
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kw.addWatch(&w)
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}
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}
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req.responseChannel <- &kubeWatcherResponse{error: nil}
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}
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}
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}
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// lifted from kubernetes/pkg/kubectl/resource_printer.go
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func printKubernetesObject(obj runtime.Object, w io.Writer) error {
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switch obj := obj.(type) {
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case *runtime.Unknown:
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var buf bytes.Buffer
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err := json.Indent(&buf, obj.Raw, "", " ")
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if err != nil {
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return err
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}
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buf.WriteRune('\n')
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_, err = buf.WriteTo(w)
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return err
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}
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data, err := json.MarshalIndent(obj, "", " ")
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if err != nil {
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return err
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}
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data = append(data, '\n')
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_, err = w.Write(data)
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return err
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}
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func (kw *KubeWatcher) createKubernetesWatch(w *fission.Watch) (watch.Interface, error) {
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var wi watch.Interface
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var err error
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listOptions := api.ListOptions{} // TODO populate labelselector and fieldselector
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// TODO handle the full list of types
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switch strings.ToUpper(w.ObjType) {
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case "POD":
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wi, err = kw.kubernetesClient.Core().Pods(w.Namespace).Watch(listOptions)
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case "SERVICE":
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wi, err = kw.kubernetesClient.Core().Services(w.Namespace).Watch(listOptions)
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default:
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msg := fmt.Sprintf("Error: unknown obj type '%v'", w.ObjType)
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log.Println(msg)
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err = errors.New(msg)
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}
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return wi, err
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}
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func (kw *KubeWatcher) addWatch(w *fission.Watch) error {
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log.Printf("Adding watch %v: %v", w.Metadata.Name, w.Function.Name)
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wi, err := kw.createKubernetesWatch(w)
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if err != nil {
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return err
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}
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ws := &watchSubscription{
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Watch: *w,
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kubeWatch: wi,
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}
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kw.watches[w.Metadata.Uid] = *ws
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go ws.eventDispatchLoop(kw.poster)
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return nil
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}
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func (kw *KubeWatcher) removeWatch(w *fission.Watch) error {
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log.Printf("Removing watch %v: %v", w.Metadata.Name, w.Function.Name)
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ws, ok := kw.watches[w.Metadata.Uid]
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if !ok {
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return fission.MakeError(fission.ErrorNotFound,
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fmt.Sprintf("watch doesn't exist: %v", w.Metadata))
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}
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ws.kubeWatch.Stop()
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delete(kw.watches, w.Metadata.Uid)
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return nil
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}
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func (ws *watchSubscription) eventDispatchLoop(poster *Poster) {
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log.Println("Listening to watch ", ws.Watch.Metadata.Name)
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for {
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ev, more := <-ws.kubeWatch.ResultChan()
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if !more {
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log.Println("Watch stopped", ws.Watch.Metadata.Name)
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return
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}
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var buf bytes.Buffer
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err := printKubernetesObject(ev.Object, &buf)
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if err != nil {
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log.Println("Failed to serialize object: %v", err)
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}
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poster.Post(string(ev.Type), ws.Watch.Url, &buf)
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}
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}
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@@ -0,0 +1,59 @@
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kubewatcher
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import (
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"log"
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"k8s.io/client-go/1.5/kubernetes"
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"k8s.io/client-go/1.5/rest"
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"github.com/platform9/fission/controller/client"
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)
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// Get a kubernetes client using the pod's service account.
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func getKubernetesClient() (*kubernetes.Clientset, error) {
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// creates the in-cluster config
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config, err := rest.InClusterConfig()
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if err != nil {
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log.Printf("Error getting kubernetes client config: %v", err)
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return nil, err
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}
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// creates the clientset
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clientset, err := kubernetes.NewForConfig(config)
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if err != nil {
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log.Printf("Error getting kubernetes client: %v", err)
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return nil, err
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}
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return clientset, nil
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}
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func Start(controllerUrl string, routerUrl string) error {
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kubeClient, err := getKubernetesClient()
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if err != nil {
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return err
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}
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poster := MakePoster(routerUrl)
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kubeWatch := MakeKubeWatcher(kubeClient, poster)
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client := client.MakeClient(controllerUrl)
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MakeWatchSync(client, kubeWatch)
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return nil
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}
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@@ -0,0 +1,59 @@
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kubewatcher
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import (
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"log"
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"time"
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"github.com/platform9/fission/controller/client"
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)
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type (
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WatchSync struct {
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client *client.Client
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kubeWatcher *KubeWatcher
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}
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)
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func MakeWatchSync(client *client.Client, kubeWatcher *KubeWatcher) *WatchSync {
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ws := &WatchSync{
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client: client,
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kubeWatcher: kubeWatcher,
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}
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go ws.syncSvc()
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return ws
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}
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func (ws *WatchSync) syncSvc() {
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failureCount := 0
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maxFailures := 6
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for {
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watches, err := ws.client.WatchList()
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if err != nil {
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failureCount++
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if failureCount > maxFailures {
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log.Fatalf("Failed to connect to controller: %v", err)
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}
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time.Sleep(10 * time.Second)
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continue
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}
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ws.kubeWatcher.Sync(watches)
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time.Sleep(3 * time.Second)
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}
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}
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@@ -0,0 +1,79 @@
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kubewatcher
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import (
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"io"
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"log"
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"net/http"
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"strings"
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)
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type (
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Poster struct {
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routerUrl string
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requestChannel chan *postRequest
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}
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postRequest struct {
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eventType string
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relativeUrl string
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body io.Reader
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}
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)
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func MakePoster(routerUrl string) *Poster {
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p := &Poster{
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routerUrl: strings.TrimSuffix(routerUrl, "/"),
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requestChannel: make(chan *postRequest, 32), // buffered channel
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}
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go p.svc()
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return p
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}
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func (p *Poster) svc() {
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for {
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r := <-p.requestChannel
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url := p.routerUrl + r.relativeUrl
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req, err := http.NewRequest("POST", url, r.body)
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if err != nil {
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log.Printf("Failed to create request to %v", r.relativeUrl)
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}
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req.Header.Add("X-Kubernetes-Event-Type", r.eventType)
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req.Header.Add("X-Fission-Request-Async", "true")
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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log.Printf("request failed: %v", r)
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// TODO retries, persistence, etc.
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}
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resp.Body.Close()
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if resp.StatusCode != 200 {
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log.Printf("request failed: %v", resp.StatusCode)
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// TODO retries etc.
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}
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}
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}
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func (p *Poster) Post(eventType, relativeUrl string, body io.Reader) {
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p.requestChannel <- &postRequest{
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eventType: eventType,
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relativeUrl: relativeUrl,
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body: body,
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}
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}
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