add custom problem detector plugin

pkg/util/tomb/tomb.go

@@ -0,0 +1,47 @@
+/*
+Copyright 2016 The Kubernetes Authors 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 tomb
+
+// Tomb is used to control the lifecycle of a goroutine.
+type Tomb struct {
+	stop chan struct{}
+	done chan struct{}
+}
+
+// NewTomb creates a new tomb.
+func NewTomb() *Tomb {
+	return &Tomb{
+		stop: make(chan struct{}),
+		done: make(chan struct{}),
+	}
+}
+
+// Stop is used to stop the goroutine outside.
+func (t *Tomb) Stop() {
+	close(t.stop)
+	<-t.done
+}
+
+// Stopping is used by the goroutine to tell whether it should stop.
+func (t *Tomb) Stopping() <-chan struct{} {
+	return t.stop
+}
+
+// Done is used by the goroutine to inform that it has stopped.
+func (t *Tomb) Done() {
+	close(t.done)
+}

pkg/util/tomb/tomb_test.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2016 The Kubernetes Authors 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 tomb
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestTomb(t *testing.T) {
+	tomb := NewTomb()
+	workflow := []string{}
+	expected := []string{"stop", "stopping", "stopped"}
+	go func() {
+		defer tomb.Done()
+		<-tomb.Stopping()
+		workflow = append(workflow, "stopping")
+	}()
+	workflow = append(workflow, "stop")
+	tomb.Stop()
+	workflow = append(workflow, "stopped")
+	if !reflect.DeepEqual(workflow, expected) {
+		t.Errorf("expected workflow %v, got %v", expected, workflow)
+	}
+}