// New wraps the datastore, providing metrics on the operations. The
// metrics are registered with names starting with prefix and a dot.
//
// If prefix is not unique, New will panic. Call Close to release the
// prefix.
func New(prefix string, ds datastore.Datastore) *measure {
m := &measure{
backend: ds,
putNum: metrics.Counter(prefix + ".Put.num"),
putErr: metrics.Counter(prefix + ".Put.err"),
putLatency: metrics.NewHistogram(prefix+".Put.latency", 0, maxLatency, 3),
putSize: metrics.NewHistogram(prefix+".Put.size", 0, maxSize, 3),
getNum: metrics.Counter(prefix + ".Get.num"),
getErr: metrics.Counter(prefix + ".Get.err"),
getLatency: metrics.NewHistogram(prefix+".Get.latency", 0, maxLatency, 3),
getSize: metrics.NewHistogram(prefix+".Get.size", 0, maxSize, 3),
hasNum: metrics.Counter(prefix + ".Has.num"),
hasErr: metrics.Counter(prefix + ".Has.err"),
hasLatency: metrics.NewHistogram(prefix+".Has.latency", 0, maxLatency, 3),
deleteNum: metrics.Counter(prefix + ".Delete.num"),
deleteErr: metrics.Counter(prefix + ".Delete.err"),
deleteLatency: metrics.NewHistogram(prefix+".Delete.latency", 0, maxLatency, 3),
queryNum: metrics.Counter(prefix + ".Query.num"),
queryErr: metrics.Counter(prefix + ".Query.err"),
queryLatency: metrics.NewHistogram(prefix+".Query.latency", 0, maxLatency, 3),
}
return m
}
func TestHistogramRemove(t *testing.T) {
metrics.Reset()
h := metrics.NewHistogram("heyo", 1, 1000, 3)
h.Remove()
_, gauges := metrics.Snapshot()
if v, ok := gauges["heyo.P50"]; ok {
t.Errorf("Gauge was %v, but expected nothing", v)
}
}
func BenchmarkHistogramRecordValue(b *testing.B) {
metrics.Reset()
h := metrics.NewHistogram("hist", 1, 1000, 3)
b.ReportAllocs()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
h.RecordValue(100)
}
})
}
func TestHistogram(t *testing.T) {
metrics.Reset()
h := metrics.NewHistogram("heyo", 1, 1000, 3)
for i := 100; i > 0; i-- {
for j := 0; j < i; j++ {
h.RecordValue(int64(i))
}
}
_, gauges := metrics.Snapshot()
if v, want := gauges["heyo.P50"], int64(71); v != want {
t.Errorf("P50 was %v, but expected %v", v, want)
}
if v, want := gauges["heyo.P75"], int64(87); v != want {
t.Errorf("P75 was %v, but expected %v", v, want)
}
if v, want := gauges["heyo.P90"], int64(95); v != want {
t.Errorf("P90 was %v, but expected %v", v, want)
}
if v, want := gauges["heyo.P95"], int64(98); v != want {
t.Errorf("P95 was %v, but expected %v", v, want)
}
if v, want := gauges["heyo.P99"], int64(100); v != want {
t.Errorf("P99 was %v, but expected %v", v, want)
}
if v, want := gauges["heyo.P999"], int64(100); v != want {
t.Errorf("P999 was %v, but expected %v", v, want)
}
}