statsd_exporter/event_test.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

80 lines
2.1 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 (
"testing"
"time"
"github.com/prometheus/statsd_exporter/pkg/clock"
)
func TestEventThresholdFlush(t *testing.T) {
c := make(chan Events, 100)
// We're not going to flush during this test, so the duration doesn't matter.
eq := newEventQueue(c, 5, time.Second)
e := make(Events, 13)
go func() {
eq.queue(e)
}()
batch := <-c
if len(batch) != 5 {
t.Fatalf("Expected event batch to be 5 elements, but got %v", len(batch))
}
batch = <-c
if len(batch) != 5 {
t.Fatalf("Expected event batch to be 5 elements, but got %v", len(batch))
}
batch = <-c
if len(batch) != 3 {
t.Fatalf("Expected event batch to be 3 elements, but got %v", len(batch))
}
}
func TestEventIntervalFlush(t *testing.T) {
// Mock a time.NewTicker
tickerCh := make(chan time.Time)
clock.ClockInstance = &clock.Clock{
TickerCh: tickerCh,
}
clock.ClockInstance.Instant = time.Unix(0, 0)
c := make(chan Events, 100)
eq := newEventQueue(c, 1000, time.Second*1000)
e := make(Events, 10)
eq.queue(e)
if eq.len() != 10 {
t.Fatal("Expected 10 events to be queued, but got", eq.len())
}
if len(eq.c) != 0 {
t.Fatal("Expected 0 events in the event channel, but got", len(eq.c))
}
// Tick time forward to trigger a flush
clock.ClockInstance.Instant = time.Unix(10000, 0)
clock.ClockInstance.TickerCh <- time.Unix(10000, 0)
events := <-eq.c
if eq.len() != 0 {
t.Fatal("Expected 0 events to be queued, but got", eq.len())
}
if len(events) != 10 {
t.Fatal("Expected 10 events in the event channel, but got", len(events))
}
}