Files
windows_exporter/internal/labelcache/labelcache_test.go
T

361 lines
11 KiB
Go

// SPDX-License-Identifier: Apache-2.0
//
// Copyright 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 labelcache_test
import (
"runtime"
"strconv"
"sync"
"testing"
"github.com/prometheus-community/windows_exporter/internal/labelcache"
"github.com/prometheus/client_golang/prometheus"
dto "github.com/prometheus/client_model/go"
"github.com/stretchr/testify/require"
"google.golang.org/protobuf/proto"
)
//nolint:gochecknoglobals
var (
counterDesc = prometheus.NewDesc("test_cpu_seconds_total", "test", []string{"process", "process_id", "mode"}, prometheus.Labels{"const": "x"})
gaugeDesc = prometheus.NewDesc("test_handles", "test", []string{"process", "process_id"}, nil)
untypedDesc = prometheus.NewDesc("test_untyped", "test", nil, nil)
wideDesc = prometheus.NewDesc("test_info", "test", []string{"a", "b", "c", "d", "e", "f", "g"}, nil)
)
func write(t *testing.T, metric prometheus.Metric) *dto.Metric {
t.Helper()
var out dto.Metric
require.NoError(t, metric.Write(&out))
return &out
}
// Cached metrics must write exactly what prometheus.MustNewConstMetric writes,
// in the first scrape (new series) and the following ones (shared labels).
func TestMustNewConstMetric(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
cases := []struct {
desc *prometheus.Desc
valueType prometheus.ValueType
values []string
}{
{counterDesc, prometheus.CounterValue, []string{"svchost", "1234", "user"}},
{counterDesc, prometheus.CounterValue, []string{"svchost", "1234", "privileged"}},
{gaugeDesc, prometheus.GaugeValue, []string{"svchost", "1234"}},
{untypedDesc, prometheus.UntypedValue, nil},
{wideDesc, prometheus.GaugeValue, []string{"1", "2", "3", "4", "5", "6", "7"}},
}
for scrapeNumber := range 3 {
scrape := cache.Begin()
for i, tc := range cases {
value := float64(scrapeNumber*10 + i)
got := scrape.MustNewConstMetric(tc.desc, tc.valueType, value, tc.values...)
want := prometheus.MustNewConstMetric(tc.desc, tc.valueType, value, tc.values...)
require.Equal(t, want.Desc(), got.Desc())
require.True(t, proto.Equal(write(t, want), write(t, got)), "scrape %d, case %d:\nwant %v\ngot %v", scrapeNumber, i, write(t, want), write(t, got))
}
scrape.Commit()
}
}
// From the second scrape on, a series reuses the label pairs of the previous
// one; series that a scrape didn't report get new pairs.
func TestLabelReuse(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
labelsOf := func(scrape *labelcache.Scrape, pid string) []*dto.LabelPair {
return write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", pid)).GetLabel()
}
scrape := cache.Begin()
first := labelsOf(scrape, "1")
labelsOf(scrape, "2")
scrape.Commit()
scrape = cache.Begin()
require.Same(t, first[0], labelsOf(scrape, "1")[0], "label pairs reused")
scrape.Commit()
// Process 2 wasn't reported in the second scrape, so its pairs were dropped.
scrape = cache.Begin()
second := labelsOf(scrape, "2")
require.Equal(t, "2", second[1].GetValue())
scrape.Commit()
scrape = cache.Begin()
require.Same(t, second[0], labelsOf(scrape, "2")[0])
scrape.Commit()
cache.Reset()
scrape = cache.Begin()
require.NotSame(t, second[0], labelsOf(scrape, "2")[0], "reset drops the cache")
scrape.Commit()
}
// A scrape begun before Reset must not restore its generation afterwards.
func TestResetDuringScrape(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
scrape := cache.Begin()
pairs := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "1")).GetLabel()
cache.Reset()
scrape.Commit()
scrape = cache.Begin()
require.NotSame(t, pairs[0], write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "1")).GetLabel()[0])
scrape.Commit()
scrape.Commit()
}
func TestInvalidLabelValues(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
scrape := cache.Begin()
require.Panics(t, func() { scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "only one") })
require.Panics(t, func() { scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "\xff") })
}
func TestConcurrentScrapes(t *testing.T) {
t.Parallel()
var (
cache labelcache.Cache
wg sync.WaitGroup
)
for range 8 {
wg.Go(func() {
for range 20 {
scrape := cache.Begin()
var inner sync.WaitGroup
for p := range 4 {
inner.Go(func() {
for pid := range 50 {
m := scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "p"+strconv.Itoa(p), strconv.Itoa(pid), "user")
if err := m.Write(&dto.Metric{}); err != nil {
t.Error(err)
}
}
})
}
inner.Wait()
scrape.Commit()
}
})
}
wg.Wait()
}
func BenchmarkMustNewConstMetric(b *testing.B) {
pids := make([]string, 500)
for i := range pids {
pids[i] = strconv.Itoa(1000 + i)
}
b.Run("prometheus", func(b *testing.B) {
b.ReportAllocs()
for b.Loop() {
for _, pid := range pids {
_ = prometheus.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "svchost", pid, "user")
}
}
})
b.Run("labelcache", func(b *testing.B) {
var cache labelcache.Cache
b.ReportAllocs()
for b.Loop() {
scrape := cache.Begin()
for _, pid := range pids {
_ = scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "svchost", pid, "user")
}
scrape.Commit()
}
})
}
//nolint:gochecknoglobals
var (
processInfoDesc = prometheus.NewDesc("test_process_info", "test", []string{"process", "process_id", "creating_process_id", "process_group_id", "owner", "cmdline"}, nil)
processDescs = func() []*prometheus.Desc {
descs := make([]*prometheus.Desc, 10)
for i := range descs {
descs[i] = prometheus.NewDesc("test_process_gauge_"+strconv.Itoa(i), "test", []string{"process", "process_id"}, nil)
}
return descs
}()
)
// benchmarkProcesses is the number of processes of the benchmarks, with 14
// series each.
const benchmarkProcesses = 1000
// scrapeProcesses emits the series of processes like the process collector:
// one info series, three counters by mode and ten gauges per process.
func scrapeProcesses(cache *labelcache.Cache) {
const processes = benchmarkProcesses
scrape := cache.Begin()
for i := range processes {
name := "process" + strconv.Itoa(i%50)
pid := strconv.Itoa(1000 + i)
_ = scrape.MustNewConstMetric(processInfoDesc, prometheus.GaugeValue, 1, name, pid, "4", pid, `NT AUTHORITY\SYSTEM`, `C:\Windows\system32\svchost.exe -k netsvcs`)
for _, mode := range []string{"user", "privileged", "other"} {
_ = scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, name, pid, mode)
}
for _, desc := range processDescs {
_ = scrape.MustNewConstMetric(desc, prometheus.GaugeValue, 1, name, pid)
}
}
scrape.Commit()
}
// BenchmarkRetained reports the heap a cache keeps between scrapes for 1000
// processes with 14 series each.
func BenchmarkRetained(b *testing.B) {
const processes = benchmarkProcesses
var stats runtime.MemStats
for b.Loop() {
runtime.GC()
runtime.ReadMemStats(&stats)
before := stats.HeapAlloc
cache := new(labelcache.Cache)
scrapeProcesses(cache)
scrapeProcesses(cache)
runtime.GC()
runtime.ReadMemStats(&stats)
b.ReportMetric(float64(int64(stats.HeapAlloc)-int64(before))/(processes*14), "retained-B/series")
runtime.KeepAlive(cache)
}
}
// BenchmarkScrape measures one steady-state scrape of 1000 processes.
func BenchmarkScrape(b *testing.B) {
var cache labelcache.Cache
scrapeProcesses(&cache)
b.ReportAllocs()
for b.Loop() {
scrapeProcesses(&cache)
}
}
// All series with the same label name and value share one pair. A pair stays
// while any cached series uses it.
func TestPairsShared(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
scrape := cache.Begin()
cpu := write(t, scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "svchost", "1234", "user")).GetLabel()
handles := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "svchost", "1234")).GetLabel()
other := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "svchost", "5678")).GetLabel()
scrape.Commit()
// counterDesc has the const label "const", so its pairs are const, mode,
// process, process_id; gaugeDesc's are process, process_id.
require.Same(t, cpu[2], handles[0], "process pair shared")
require.Same(t, cpu[3], handles[1], "process_id pair shared")
require.Same(t, handles[0], other[0], "process pair shared across processes")
require.NotSame(t, handles[1], other[1])
// Only the gauge of process 1234 is reported: its pairs stay.
scrape = cache.Begin()
again := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 2, "svchost", "1234")).GetLabel()
scrape.Commit()
require.Same(t, handles[1], again[1])
// Process 5678 disappeared, so its process_id pair was dropped with it.
scrape = cache.Begin()
back := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "svchost", "5678")).GetLabel()
scrape.Commit()
require.NotSame(t, other[1], back[1])
require.Equal(t, other[1].GetValue(), back[1].GetValue())
}
// A call with too few label values must still panic when a series with
// empty trailing values is cached.
func TestShortKeyCardinality(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
scrape := cache.Begin()
_ = scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "a", "b", "")
require.Panics(t, func() { scrape.MustNewConstMetric(counterDesc, prometheus.CounterValue, 1, "a", "b") })
scrape.Commit()
}
// After Commit, a scrape no longer adds series to the cache.
func TestCommittedScrape(t *testing.T) {
t.Parallel()
var cache labelcache.Cache
scrape := cache.Begin()
first := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "1")).GetLabel()
scrape.Commit()
late := write(t, scrape.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "2")).GetLabel()
next := cache.Begin()
require.Same(t, first[0], write(t, next.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "1")).GetLabel()[0])
require.NotSame(t, late[1], write(t, next.MustNewConstMetric(gaugeDesc, prometheus.GaugeValue, 1, "p", "2")).GetLabel()[1], "late series was not cached")
next.Commit()
}