statsd_exporter/event.go
Clayton O'Neill c7e76967c8
Add internal event queuing and flushing
At high traffic levels, the locking around sending on channels can cause
a large amount of blocking and CPU usage.  These adds an event queue
mechanism so that events are queued for short period of time, and
flushed in batches to the main exporter goroutine periodically.

The default is is to flush every 1000 events, or every 200ms, whichever
happens first.

Signed-off-by: Clayton O'Neill <claytono@github.com>
2019-06-04 06:57:48 -04:00

132 lines
3.2 KiB
Go

// Copyright 2013 The Prometheus Authors
// 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 main
import (
"sync"
"time"
"github.com/prometheus/statsd_exporter/pkg/clock"
"github.com/prometheus/statsd_exporter/pkg/mapper"
)
type Event interface {
MetricName() string
Value() float64
Labels() map[string]string
MetricType() mapper.MetricType
}
type CounterEvent struct {
metricName string
value float64
labels map[string]string
}
func (c *CounterEvent) MetricName() string { return c.metricName }
func (c *CounterEvent) Value() float64 { return c.value }
func (c *CounterEvent) Labels() map[string]string { return c.labels }
func (c *CounterEvent) MetricType() mapper.MetricType { return mapper.MetricTypeCounter }
type GaugeEvent struct {
metricName string
value float64
relative bool
labels map[string]string
}
func (g *GaugeEvent) MetricName() string { return g.metricName }
func (g *GaugeEvent) Value() float64 { return g.value }
func (c *GaugeEvent) Labels() map[string]string { return c.labels }
func (c *GaugeEvent) MetricType() mapper.MetricType { return mapper.MetricTypeGauge }
type TimerEvent struct {
metricName string
value float64
labels map[string]string
}
func (t *TimerEvent) MetricName() string { return t.metricName }
func (t *TimerEvent) Value() float64 { return t.value }
func (c *TimerEvent) Labels() map[string]string { return c.labels }
func (c *TimerEvent) MetricType() mapper.MetricType { return mapper.MetricTypeTimer }
type Events []Event
type eventQueue struct {
c chan Events
q Events
m sync.Mutex
flushThreshold int
flushTicker *time.Ticker
}
type eventHandler interface {
queue(event Events)
}
func newEventQueue(c chan Events, flushThreshold int, flushInterval time.Duration) *eventQueue {
ticker := clock.NewTicker(flushInterval)
eq := &eventQueue{
c: c,
flushThreshold: flushThreshold,
flushTicker: ticker,
}
go func() {
for {
<-ticker.C
eq.flush()
}
}()
return eq
}
func (eq *eventQueue) queue(events Events) {
eq.m.Lock()
defer eq.m.Unlock()
for _, e := range events {
eq.q = append(eq.q, e)
if len(eq.q) >= eq.flushThreshold {
eq.flushUnlocked()
}
}
}
func (eq *eventQueue) flush() {
eq.m.Lock()
defer eq.m.Unlock()
eq.flushUnlocked()
}
func (eq *eventQueue) flushUnlocked() {
eq.c <- eq.q
eq.q = eq.q[:0]
eventsFlushed.Inc()
}
func (eq *eventQueue) len() int {
eq.m.Lock()
defer eq.m.Unlock()
return len(eq.q)
}
type unbufferedEventHandler struct {
c chan Events
}
func (ueh *unbufferedEventHandler) queue(events Events) {
ueh.c <- events
}