Fix up usage and tests, split into multiple files.

Doing this in multiple commits in an attempt to preserve the file movement history.

pkg/scheduler/random.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2014 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 scheduler
+
+import (
+	"math/rand"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+)
+
+// RandomScheduler choses machines uniformly at random.
+type RandomScheduler struct {
+	// TODO: rand.Rand is *NOT* thread safe.
+	random *rand.Rand
+}
+
+func MakeRandomScheduler(random *rand.Rand) Scheduler {
+	return &RandomScheduler{
+		random: random,
+	}
+}
+
+func (s *RandomScheduler) Schedule(pod api.Pod, minionLister MinionLister) (string, error) {
+	machines, err := minionLister.List()
+	if err != nil {
+		return "", err
+	}
+	return machines[s.random.Int()%len(machines)], nil
+}