github.com/aclisp/heapster@v0.19.2-0.20160613100040-51756f899a96/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  	"github.com/golang/glog"
    21  	"github.com/prometheus/client_golang/prometheus"
    22  	"k8s.io/heapster/events/core"
    23  )
    24  
    25  var (
    26  	// Last time of eventer housekeep since unix epoch in seconds
    27  	lastHousekeepTimestamp = prometheus.NewGauge(
    28  		prometheus.GaugeOpts{
    29  			Namespace: "eventer",
    30  			Subsystem: "manager",
    31  			Name:      "last_time_seconds",
    32  			Help:      "Last time of eventer housekeep since unix epoch in seconds.",
    33  		})
    34  )
    35  
    36  func init() {
    37  	prometheus.MustRegister(lastHousekeepTimestamp)
    38  }
    39  
    40  type Manager interface {
    41  	Start()
    42  	Stop()
    43  }
    44  
    45  type realManager struct {
    46  	source    core.EventSource
    47  	sink      core.EventSink
    48  	frequency time.Duration
    49  	stopChan  chan struct{}
    50  }
    51  
    52  func NewManager(source core.EventSource, sink core.EventSink, frequency time.Duration) (Manager, error) {
    53  	manager := realManager{
    54  		source:    source,
    55  		sink:      sink,
    56  		frequency: frequency,
    57  		stopChan:  make(chan struct{}),
    58  	}
    59  
    60  	return &manager, nil
    61  }
    62  
    63  func (rm *realManager) Start() {
    64  	go rm.Housekeep()
    65  }
    66  
    67  func (rm *realManager) Stop() {
    68  	rm.stopChan <- struct{}{}
    69  }
    70  
    71  func (rm *realManager) Housekeep() {
    72  	for {
    73  		// Try to infovke housekeep at fixed time.
    74  		now := time.Now()
    75  		start := now.Truncate(rm.frequency)
    76  		end := start.Add(rm.frequency)
    77  		timeToNextSync := end.Sub(now)
    78  
    79  		select {
    80  		case <-time.After(timeToNextSync):
    81  			rm.housekeep()
    82  		case <-rm.stopChan:
    83  			rm.sink.Stop()
    84  			return
    85  		}
    86  	}
    87  }
    88  
    89  func (rm *realManager) housekeep() {
    90  	defer lastHousekeepTimestamp.Set(float64(time.Now().Unix()))
    91  
    92  	// No parallelism. Assumes that the events are pushed to Heapster. Add paralellism
    93  	// when this stops to be true.
    94  	events := rm.source.GetNewEvents()
    95  	glog.V(0).Infof("Exporting %d events", len(events.Events))
    96  	rm.sink.ExportEvents(events)
    97  }