github.com/timstclair/heapster@v0.20.0-alpha1/events/manager/manager.go (about)

     1  // Copyright 2015 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package manager
    16  
    17  import (
    18  	"time"
    19  
    20  	"k8s.io/heapster/events/core"
    21  
    22  	"github.com/golang/glog"
    23  )
    24  
    25  type Manager interface {
    26  	Start()
    27  	Stop()
    28  }
    29  
    30  type realManager struct {
    31  	source    core.EventSource
    32  	sink      core.EventSink
    33  	frequency time.Duration
    34  	stopChan  chan struct{}
    35  }
    36  
    37  func NewManager(source core.EventSource, sink core.EventSink, frequency time.Duration) (Manager, error) {
    38  	manager := realManager{
    39  		source:    source,
    40  		sink:      sink,
    41  		frequency: frequency,
    42  		stopChan:  make(chan struct{}),
    43  	}
    44  
    45  	return &manager, nil
    46  }
    47  
    48  func (rm *realManager) Start() {
    49  	go rm.Housekeep()
    50  }
    51  
    52  func (rm *realManager) Stop() {
    53  	rm.stopChan <- struct{}{}
    54  }
    55  
    56  func (rm *realManager) Housekeep() {
    57  	for {
    58  		// Try to infovke housekeep at fixed time.
    59  		now := time.Now()
    60  		start := now.Truncate(rm.frequency)
    61  		end := start.Add(rm.frequency)
    62  		timeToNextSync := end.Sub(now)
    63  
    64  		select {
    65  		case <-time.After(timeToNextSync):
    66  			rm.housekeep()
    67  		case <-rm.stopChan:
    68  			rm.sink.Stop()
    69  			return
    70  		}
    71  	}
    72  }
    73  
    74  func (rm *realManager) housekeep() {
    75  	// No parallelism. Assumes that the events are pushed to Heapster. Add paralellism
    76  	// when this stops to be true.
    77  	events := rm.source.GetNewEvents()
    78  	glog.V(0).Infof("Exporting %d events", len(events.Events))
    79  	rm.sink.ExportEvents(events)
    80  }