Begin a controller framework.

pkg/controller/framework/controller_test.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package framework_test
+
+import (
+	"fmt"
+	"sync"
+	"time"
+	// "testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/cache"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/controller/framework"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+)
+
+func Example() {
+	// source simulates an apiserver object endpoint.
+	source := framework.NewFakeControllerSource()
+
+	// This will hold the downstream state, as we know it.
+	downstream := cache.NewStore(cache.MetaNamespaceKeyFunc)
+
+	// This will hold incoming changes. Note how we pass downstream in as a
+	// KeyLister, that way resync operations will result in the correct set
+	// of update/delete deltas.
+	fifo := cache.NewDeltaFIFO(cache.MetaNamespaceKeyFunc, nil, downstream)
+
+	// Let's do threadsafe output to get predictable test results.
+	outputSetLock := sync.Mutex{}
+	outputSet := util.StringSet{}
+
+	cfg := &framework.Config{
+		Queue:            fifo,
+		ListerWatcher:    source,
+		ObjectType:       &api.Pod{},
+		FullResyncPeriod: time.Millisecond * 100,
+		RetryOnError:     false,
+
+		// Let's implement a simple controller that just deletes
+		// everything that comes in.
+		Process: func(obj interface{}) error {
+			// Obj is from the Pop method of the Queue we make above.
+			newest := obj.(cache.Deltas).Newest()
+
+			if newest.Type != cache.Deleted {
+				// Update our downstream store.
+				err := downstream.Add(newest.Object)
+				if err != nil {
+					return err
+				}
+
+				source.Delete(newest.Object.(runtime.Object))
+			} else {
+				// Update our downstream store.
+				err := downstream.Delete(newest.Object)
+				if err != nil {
+					return err
+				}
+
+				// fifo's KeyOf is easiest, because it handles
+				// DeletedFinalStateUnknown markers.
+				key, err := fifo.KeyOf(newest.Object)
+				if err != nil {
+					return err
+				}
+
+				// Record some output.
+				outputSetLock.Lock()
+				defer outputSetLock.Unlock()
+				outputSet.Insert(key)
+			}
+			return nil
+		},
+	}
+
+	// Create the controller and run it until we close stop.
+	stop := make(chan struct{})
+	framework.New(cfg).Run(stop)
+
+	// Let's add a few objects to the source.
+	for _, name := range []string{"a-hello", "b-controller", "c-framework"} {
+		// Note that these pods are not valid-- the fake source doesn't
+		// call validation or anything.
+		source.Add(&api.Pod{ObjectMeta: api.ObjectMeta{Name: name}})
+	}
+
+	// Let's wait for the controller to process the things we just added.
+	time.Sleep(500 * time.Millisecond)
+	close(stop)
+
+	outputSetLock.Lock()
+	for _, key := range outputSet.List() {
+		fmt.Println(key)
+	}
+	// Output:
+	// a-hello
+	// b-controller
+	// c-framework
+}