Move scheduler components into their own packages

- rename scheduler.{operations -> components}
- move each component into its own directory with doc.go file, for proper
  access isolation

contrib/mesos/pkg/scheduler/components/errorhandler/errorhandler.go

@@ -0,0 +1,109 @@
+/*
+Copyright 2015 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 errorhandler
+
+import (
+	log "github.com/golang/glog"
+	mesos "github.com/mesos/mesos-go/mesosproto"
+	"k8s.io/kubernetes/contrib/mesos/pkg/backoff"
+	"k8s.io/kubernetes/contrib/mesos/pkg/queue"
+	merrors "k8s.io/kubernetes/contrib/mesos/pkg/scheduler/errors"
+	"k8s.io/kubernetes/contrib/mesos/pkg/scheduler/podschedulers"
+	"k8s.io/kubernetes/contrib/mesos/pkg/scheduler/podtask"
+	"k8s.io/kubernetes/contrib/mesos/pkg/scheduler/queuer"
+	types "k8s.io/kubernetes/contrib/mesos/pkg/scheduler/types"
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/util"
+)
+
+type ErrorHandler struct {
+	sched        types.Scheduler
+	backoff      *backoff.Backoff
+	qr           *queuer.Queuer
+	podScheduler podschedulers.PodScheduler
+}
+
+func NewErrorHandler(sched types.Scheduler, backoff *backoff.Backoff, qr *queuer.Queuer, podScheduler podschedulers.PodScheduler) *ErrorHandler {
+	return &ErrorHandler{
+		sched:        sched,
+		backoff:      backoff,
+		qr:           qr,
+		podScheduler: podScheduler,
+	}
+}
+
+// implementation of scheduling plugin's Error func; see plugin/pkg/scheduler
+func (k *ErrorHandler) Error(pod *api.Pod, schedulingErr error) {
+
+	if schedulingErr == merrors.NoSuchPodErr {
+		log.V(2).Infof("Not rescheduling non-existent pod %v", pod.Name)
+		return
+	}
+
+	log.Infof("Error scheduling %v: %v; retrying", pod.Name, schedulingErr)
+	defer util.HandleCrash()
+
+	// default upstream scheduler passes pod.Name as binding.PodID
+	ctx := api.WithNamespace(api.NewDefaultContext(), pod.Namespace)
+	podKey, err := podtask.MakePodKey(ctx, pod.Name)
+	if err != nil {
+		log.Errorf("Failed to construct pod key, aborting scheduling for pod %v: %v", pod.Name, err)
+		return
+	}
+
+	k.backoff.GC()
+	k.sched.Lock()
+	defer k.sched.Unlock()
+
+	switch task, state := k.sched.Tasks().ForPod(podKey); state {
+	case podtask.StateUnknown:
+		// if we don't have a mapping here any more then someone deleted the pod
+		log.V(2).Infof("Could not resolve pod to task, aborting pod reschdule: %s", podKey)
+		return
+
+	case podtask.StatePending:
+		if task.Has(podtask.Launched) {
+			log.V(2).Infof("Skipping re-scheduling for already-launched pod %v", podKey)
+			return
+		}
+		breakoutEarly := queue.BreakChan(nil)
+		if schedulingErr == podschedulers.NoSuitableOffersErr {
+			log.V(3).Infof("adding backoff breakout handler for pod %v", podKey)
+			breakoutEarly = queue.BreakChan(k.sched.Offers().Listen(podKey, func(offer *mesos.Offer) bool {
+				k.sched.Lock()
+				defer k.sched.Unlock()
+				switch task, state := k.sched.Tasks().Get(task.ID); state {
+				case podtask.StatePending:
+					// Assess fitness of pod with the current offer. The scheduler normally
+					// "backs off" when it can't find an offer that matches up with a pod.
+					// The backoff period for a pod can terminate sooner if an offer becomes
+					// available that matches up.
+					return !task.Has(podtask.Launched) && k.podScheduler.FitPredicate()(task, offer, nil)
+				default:
+					// no point in continuing to check for matching offers
+					return true
+				}
+			}))
+		}
+		delay := k.backoff.Get(podKey)
+		log.V(3).Infof("requeuing pod %v with delay %v", podKey, delay)
+		k.qr.Requeue(&queuer.Pod{Pod: pod, Delay: &delay, Notify: breakoutEarly})
+
+	default:
+		log.V(2).Infof("Task is no longer pending, aborting reschedule for pod %v", podKey)
+	}
+}