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Use the runtime/metrics package for the Go collector for 1.17+ (#955) 

This change introduces use of the runtime/metrics package in place of
runtime.MemStats for Go 1.17 or later. The runtime/metrics package was
introduced in Go 1.16, but not all the old metrics were accounted for
until 1.17.

The runtime/metrics package offers several advantages over using
runtime.MemStats:
* The list of metrics and their descriptions are machine-readable,
  allowing new metrics to get added without any additional work.
* Detailed histogram-based metrics are now available, offering much
  deeper insights into the Go runtime.
* The runtime/metrics API is significantly more efficient than
  runtime.MemStats, even with the additional metrics added, because
  it does not require any stop-the-world events.

That being said, integrating the package comes with some caveats, some
of which were discussed in #842. Namely:
* The old MemStats-based metrics need to continue working, so they're
  exported under their old names backed by equivalent runtime/metrics
  metrics.
* Earlier versions of Go need to continue working, so the old code
  remains, but behind a build tag.

Finally, a few notes about the implementation:
* This change includes a whole bunch of refactoring to avoid significant
  code duplication.
* This change adds a new histogram metric type specifically optimized
  for runtime/metrics histograms. This type's methods also include
  additional logic to deal with differences in bounds conventions.
* This change makes a whole bunch of decisions about how runtime/metrics
  names are translated.
* This change adds a `go generate` script to generate a list of expected
  runtime/metrics names for a given Go version for auditing. Users of
  new versions of Go will transparently be allowed to use new metrics,
  however.

Signed-off-by: Michael Anthony Knyszek <mknyszek@google.com>
This commit is contained in:
Michael Knyszek 2022-01-16 11:41:56 -05:00 committed by GitHub
parent dc1559e8ef
commit 22da9497b8
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 1449 additions and 383 deletions
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38
prometheus/build_info_collector.go Normal file
View File

@ -0,0 +1,38 @@
// Copyright 2021 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 prometheus
import "runtime/debug"
// NewBuildInfoCollector is the obsolete version of collectors.NewBuildInfoCollector.
// See there for documentation.
//
// Deprecated: Use collectors.NewBuildInfoCollector instead.
func NewBuildInfoCollector() Collector {
path, version, sum := "unknown", "unknown", "unknown"
if bi, ok := debug.ReadBuildInfo(); ok {
path = bi.Main.Path
version = bi.Main.Version
sum = bi.Main.Sum
}
c := &selfCollector{MustNewConstMetric(
NewDesc(
"go_build_info",
"Build information about the main Go module.",
nil, Labels{"path": path, "version": version, "checksum": sum},
),
GaugeValue, 1)}
c.init(c.self)
return c
}

8
prometheus/counter.go
View File

@ -133,10 +133,14 @@ func (c *counter) Inc() {
atomic.AddUint64(&c.valInt, 1)
}
func (c *counter) Write(out *dto.Metric) error {
func (c *counter) get() float64 {
fval := math.Float64frombits(atomic.LoadUint64(&c.valBits))
ival := atomic.LoadUint64(&c.valInt)
val := fval + float64(ival)
return fval + float64(ival)
}
func (c *counter) Write(out *dto.Metric) error {
val := c.get()
var exemplar *dto.Exemplar
if e := c.exemplar.Load(); e != nil {

115
prometheus/gen_go_collector_metrics_set.go Normal file
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@ -0,0 +1,115 @@
// Copyright 2021 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.
//go:build ignore
// +build ignore
package main
import (
"bytes"
"fmt"
"go/format"
"log"
"os"
"runtime/metrics"
"strconv"
"strings"
"text/template"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/internal"
)
func main() {
if len(os.Args) != 2 {
log.Fatal("requires Go version (e.g. go1.17) as an argument")
}
version, err := parseVersion(os.Args[1])
if err != nil {
log.Fatalf("parsing Go version: %v", err)
}
// Generate code.
var buf bytes.Buffer
err = testFile.Execute(&buf, struct {
Descriptions []metrics.Description
GoVersion goVersion
}{
Descriptions: metrics.All(),
GoVersion: version,
})
if err != nil {
log.Fatalf("executing template: %v", err)
}
// Format it.
result, err := format.Source(buf.Bytes())
if err != nil {
log.Fatalf("formatting code: %v", err)
}
// Write it to a file.
fname := fmt.Sprintf("go_collector_metrics_%s_test.go", version.Abbr())
if err := os.WriteFile(fname, result, 0o644); err != nil {
log.Fatalf("writing file: %v", err)
}
}
type goVersion int
func (g goVersion) String() string {
return fmt.Sprintf("go1.%d", g)
}
func (g goVersion) Abbr() string {
return fmt.Sprintf("go1%d", g)
}
func parseVersion(s string) (goVersion, error) {
i := strings.IndexRune(s, '.')
if i < 0 {
return goVersion(-1), fmt.Errorf("bad Go version format")
}
i, err := strconv.Atoi(s[i+1:])
return goVersion(i), err
}
var testFile = template.Must(template.New("testFile").Funcs(map[string]interface{}{
"rm2prom": func(d metrics.Description) string {
ns, ss, n, ok := internal.RuntimeMetricsToProm(&d)
if !ok {
return ""
}
return prometheus.BuildFQName(ns, ss, n)
},
"nextVersion": func(version goVersion) string {
return (version + goVersion(1)).String()
},
}).Parse(`// Code generated by gen_go_collector_metrics_set.go; DO NOT EDIT.
//go:generate go run gen_go_collector_metrics_set.go {{.GoVersion}}
//go:build {{.GoVersion}} && !{{nextVersion .GoVersion}}
// +build {{.GoVersion}},!{{nextVersion .GoVersion}}
package prometheus
var expectedRuntimeMetrics = map[string]string{
{{- range .Descriptions -}}
{{- $trans := rm2prom . -}}
{{- if ne $trans "" }}
{{.Name | printf "%q"}}: {{$trans | printf "%q"}},
{{- end -}}
{{end}}
}
`))

494
prometheus/go_collector.go
View File

@ -16,32 +16,209 @@ package prometheus
import (
"runtime"
"runtime/debug"
"sync"
"time"
)
type goCollector struct {
func goRuntimeMemStats() memStatsMetrics {
return memStatsMetrics{
{
desc: NewDesc(
memstatNamespace("alloc_bytes"),
"Number of bytes allocated and still in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Alloc) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("alloc_bytes_total"),
"Total number of bytes allocated, even if freed.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.TotalAlloc) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("sys_bytes"),
"Number of bytes obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Sys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("lookups_total"),
"Total number of pointer lookups.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Lookups) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("mallocs_total"),
"Total number of mallocs.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Mallocs) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("frees_total"),
"Total number of frees.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Frees) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("heap_alloc_bytes"),
"Number of heap bytes allocated and still in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapAlloc) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_sys_bytes"),
"Number of heap bytes obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_idle_bytes"),
"Number of heap bytes waiting to be used.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapIdle) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_inuse_bytes"),
"Number of heap bytes that are in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_released_bytes"),
"Number of heap bytes released to OS.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapReleased) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_objects"),
"Number of allocated objects.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapObjects) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("stack_inuse_bytes"),
"Number of bytes in use by the stack allocator.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.StackInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("stack_sys_bytes"),
"Number of bytes obtained from system for stack allocator.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.StackSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mspan_inuse_bytes"),
"Number of bytes in use by mspan structures.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MSpanInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mspan_sys_bytes"),
"Number of bytes used for mspan structures obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MSpanSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mcache_inuse_bytes"),
"Number of bytes in use by mcache structures.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MCacheInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mcache_sys_bytes"),
"Number of bytes used for mcache structures obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MCacheSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("buck_hash_sys_bytes"),
"Number of bytes used by the profiling bucket hash table.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.BuckHashSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("gc_sys_bytes"),
"Number of bytes used for garbage collection system metadata.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.GCSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("other_sys_bytes"),
"Number of bytes used for other system allocations.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.OtherSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("next_gc_bytes"),
"Number of heap bytes when next garbage collection will take place.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.NextGC) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("gc_cpu_fraction"),
"The fraction of this program's available CPU time used by the GC since the program started.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
valType: GaugeValue,
},
}
}
type baseGoCollector struct {
goroutinesDesc *Desc
threadsDesc *Desc
gcDesc *Desc
gcLastTimeDesc *Desc
goInfoDesc *Desc
// ms... are memstats related.
msLast *runtime.MemStats // Previously collected memstats.
msLastTimestamp time.Time
msMtx sync.Mutex // Protects msLast and msLastTimestamp.
msMetrics memStatsMetrics
msRead func(*runtime.MemStats) // For mocking in tests.
msMaxWait time.Duration // Wait time for fresh memstats.
msMaxAge time.Duration // Maximum allowed age of old memstats.
}
// NewGoCollector is the obsolete version of collectors.NewGoCollector.
// See there for documentation.
//
// Deprecated: Use collectors.NewGoCollector instead.
func NewGoCollector() Collector {
return &goCollector{
func newBaseGoCollector() baseGoCollector {
return baseGoCollector{
goroutinesDesc: NewDesc(
"go_goroutines",
"Number of goroutines that currently exist.",
@ -54,243 +231,28 @@ func NewGoCollector() Collector {
"go_gc_duration_seconds",
"A summary of the pause duration of garbage collection cycles.",
nil, nil),
gcLastTimeDesc: NewDesc(
memstatNamespace("last_gc_time_seconds"),
"Number of seconds since 1970 of last garbage collection.",
nil, nil),
goInfoDesc: NewDesc(
"go_info",
"Information about the Go environment.",
nil, Labels{"version": runtime.Version()}),
msLast: &runtime.MemStats{},
msRead: runtime.ReadMemStats,
msMaxWait: time.Second,
msMaxAge: 5 * time.Minute,
msMetrics: memStatsMetrics{
{
desc: NewDesc(
memstatNamespace("alloc_bytes"),
"Number of bytes allocated and still in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Alloc) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("alloc_bytes_total"),
"Total number of bytes allocated, even if freed.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.TotalAlloc) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("sys_bytes"),
"Number of bytes obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Sys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("lookups_total"),
"Total number of pointer lookups.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Lookups) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("mallocs_total"),
"Total number of mallocs.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Mallocs) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("frees_total"),
"Total number of frees.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.Frees) },
valType: CounterValue,
}, {
desc: NewDesc(
memstatNamespace("heap_alloc_bytes"),
"Number of heap bytes allocated and still in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapAlloc) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_sys_bytes"),
"Number of heap bytes obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_idle_bytes"),
"Number of heap bytes waiting to be used.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapIdle) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_inuse_bytes"),
"Number of heap bytes that are in use.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_released_bytes"),
"Number of heap bytes released to OS.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapReleased) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("heap_objects"),
"Number of allocated objects.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.HeapObjects) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("stack_inuse_bytes"),
"Number of bytes in use by the stack allocator.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.StackInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("stack_sys_bytes"),
"Number of bytes obtained from system for stack allocator.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.StackSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mspan_inuse_bytes"),
"Number of bytes in use by mspan structures.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MSpanInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mspan_sys_bytes"),
"Number of bytes used for mspan structures obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MSpanSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mcache_inuse_bytes"),
"Number of bytes in use by mcache structures.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MCacheInuse) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("mcache_sys_bytes"),
"Number of bytes used for mcache structures obtained from system.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.MCacheSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("buck_hash_sys_bytes"),
"Number of bytes used by the profiling bucket hash table.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.BuckHashSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("gc_sys_bytes"),
"Number of bytes used for garbage collection system metadata.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.GCSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("other_sys_bytes"),
"Number of bytes used for other system allocations.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.OtherSys) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("next_gc_bytes"),
"Number of heap bytes when next garbage collection will take place.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.NextGC) },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("last_gc_time_seconds"),
"Number of seconds since 1970 of last garbage collection.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return float64(ms.LastGC) / 1e9 },
valType: GaugeValue,
}, {
desc: NewDesc(
memstatNamespace("gc_cpu_fraction"),
"The fraction of this program's available CPU time used by the GC since the program started.",
nil, nil,
),
eval: func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
valType: GaugeValue,
},
},
}
}
func memstatNamespace(s string) string {
return "go_memstats_" + s
}
// Describe returns all descriptions of the collector.
func (c *goCollector) Describe(ch chan<- *Desc) {
func (c *baseGoCollector) Describe(ch chan<- *Desc) {
ch <- c.goroutinesDesc
ch <- c.threadsDesc
ch <- c.gcDesc
ch <- c.gcLastTimeDesc
ch <- c.goInfoDesc
for _, i := range c.msMetrics {
ch <- i.desc
}
}
// Collect returns the current state of all metrics of the collector.
func (c *goCollector) Collect(ch chan<- Metric) {
var (
ms = &runtime.MemStats{}
done = make(chan struct{})
)
// Start reading memstats first as it might take a while.
go func() {
c.msRead(ms)
c.msMtx.Lock()
c.msLast = ms
c.msLastTimestamp = time.Now()
c.msMtx.Unlock()
close(done)
}()
func (c *baseGoCollector) Collect(ch chan<- Metric) {
ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
n, _ := runtime.ThreadCreateProfile(nil)
ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
@ -305,63 +267,19 @@ func (c *goCollector) Collect(ch chan<- Metric) {
}
quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
ch <- MustNewConstMetric(c.gcLastTimeDesc, GaugeValue, float64(stats.LastGC.UnixNano())/1e9)
ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
timer := time.NewTimer(c.msMaxWait)
select {
case <-done: // Our own ReadMemStats succeeded in time. Use it.
timer.Stop() // Important for high collection frequencies to not pile up timers.
c.msCollect(ch, ms)
return
case <-timer.C: // Time out, use last memstats if possible. Continue below.
}
c.msMtx.Lock()
if time.Since(c.msLastTimestamp) < c.msMaxAge {
// Last memstats are recent enough. Collect from them under the lock.
c.msCollect(ch, c.msLast)
c.msMtx.Unlock()
return
}
// If we are here, the last memstats are too old or don't exist. We have
// to wait until our own ReadMemStats finally completes. For that to
// happen, we have to release the lock.
c.msMtx.Unlock()
<-done
c.msCollect(ch, ms)
}
func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
for _, i := range c.msMetrics {
ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
}
func memstatNamespace(s string) string {
return "go_memstats_" + s
}
// memStatsMetrics provide description, value, and value type for memstat metrics.
// memStatsMetrics provide description, evaluator, runtime/metrics name, and
// value type for memstat metrics.
type memStatsMetrics []struct {
desc *Desc
eval func(*runtime.MemStats) float64
valType ValueType
}
// NewBuildInfoCollector is the obsolete version of collectors.NewBuildInfoCollector.
// See there for documentation.
//
// Deprecated: Use collectors.NewBuildInfoCollector instead.
func NewBuildInfoCollector() Collector {
path, version, sum := "unknown", "unknown", "unknown"
if bi, ok := debug.ReadBuildInfo(); ok {
path = bi.Main.Path
version = bi.Main.Version
sum = bi.Main.Sum
}
c := &selfCollector{MustNewConstMetric(
NewDesc(
"go_build_info",
"Build information about the main Go module.",
nil, Labels{"path": path, "version": version, "checksum": sum},
),
GaugeValue, 1)}
c.init(c.self)
return c
}

107
prometheus/go_collector_go116.go Normal file
View File

@ -0,0 +1,107 @@
// Copyright 2021 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.
//go:build !go1.17
// +build !go1.17
package prometheus
import (
"runtime"
"sync"
"time"
)
type goCollector struct {
base baseGoCollector
// ms... are memstats related.
msLast *runtime.MemStats // Previously collected memstats.
msLastTimestamp time.Time
msMtx sync.Mutex // Protects msLast and msLastTimestamp.
msMetrics memStatsMetrics
msRead func(*runtime.MemStats) // For mocking in tests.
msMaxWait time.Duration // Wait time for fresh memstats.
msMaxAge time.Duration // Maximum allowed age of old memstats.
}
// NewGoCollector is the obsolete version of collectors.NewGoCollector.
// See there for documentation.
//
// Deprecated: Use collectors.NewGoCollector instead.
func NewGoCollector() Collector {
return &goCollector{
base: newBaseGoCollector(),
msLast: &runtime.MemStats{},
msRead: runtime.ReadMemStats,
msMaxWait: time.Second,
msMaxAge: 5 * time.Minute,
msMetrics: goRuntimeMemStats(),
}
}
// Describe returns all descriptions of the collector.
func (c *goCollector) Describe(ch chan<- *Desc) {
c.base.Describe(ch)
for _, i := range c.msMetrics {
ch <- i.desc
}
}
// Collect returns the current state of all metrics of the collector.
func (c *goCollector) Collect(ch chan<- Metric) {
var (
ms = &runtime.MemStats{}
done = make(chan struct{})
)
// Start reading memstats first as it might take a while.
go func() {
c.msRead(ms)
c.msMtx.Lock()
c.msLast = ms
c.msLastTimestamp = time.Now()
c.msMtx.Unlock()
close(done)
}()
// Collect base non-memory metrics.
c.base.Collect(ch)
timer := time.NewTimer(c.msMaxWait)
select {
case <-done: // Our own ReadMemStats succeeded in time. Use it.
timer.Stop() // Important for high collection frequencies to not pile up timers.
c.msCollect(ch, ms)
return
case <-timer.C: // Time out, use last memstats if possible. Continue below.
}
c.msMtx.Lock()
if time.Since(c.msLastTimestamp) < c.msMaxAge {
// Last memstats are recent enough. Collect from them under the lock.
c.msCollect(ch, c.msLast)
c.msMtx.Unlock()
return
}
// If we are here, the last memstats are too old or don't exist. We have
// to wait until our own ReadMemStats finally completes. For that to
// happen, we have to release the lock.
c.msMtx.Unlock()
<-done
c.msCollect(ch, ms)
}
func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
for _, i := range c.msMetrics {
ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
}
}

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// Copyright 2021 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.
//go:build !go1.17
// +build !go1.17
package prometheus
import (
"runtime"
"testing"
"time"
dto "github.com/prometheus/client_model/go"
)
func TestGoCollectorMemStats(t *testing.T) {
var (
c = NewGoCollector().(*goCollector)
got uint64
)
checkCollect := func(want uint64) {
metricCh := make(chan Metric)
endCh := make(chan struct{})
go func() {
c.Collect(metricCh)
close(endCh)
}()
Collect:
for {
select {
case metric := <-metricCh:
if metric.Desc().fqName != "go_memstats_alloc_bytes" {
continue Collect
}
pb := &dto.Metric{}
metric.Write(pb)
got = uint64(pb.GetGauge().GetValue())
case <-endCh:
break Collect
}
}
if want != got {
t.Errorf("unexpected value of go_memstats_alloc_bytes, want %d, got %d", want, got)
}
}
// Speed up the timing to make the test faster.
c.msMaxWait = 5 * time.Millisecond
c.msMaxAge = 50 * time.Millisecond
// Scenario 1: msRead responds slowly, no previous memstats available,
// msRead is executed anyway.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 1
}
checkCollect(1)
// Now msLast is set.
c.msMtx.Lock()
if want, got := uint64(1), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 2: msRead responds fast, previous memstats available, new
// value collected.
c.msRead = func(ms *runtime.MemStats) {
ms.Alloc = 2
}
checkCollect(2)
// msLast is set, too.
c.msMtx.Lock()
if want, got := uint64(2), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 3: msRead responds slowly, previous memstats available, old
// value collected.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 3
}
checkCollect(2)
// After waiting, new value is still set in msLast.
time.Sleep(80 * time.Millisecond)
c.msMtx.Lock()
if want, got := uint64(3), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 4: msRead responds slowly, previous memstats is too old, new
// value collected.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 4
}
checkCollect(4)
c.msMtx.Lock()
if want, got := uint64(4), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
}

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// Copyright 2021 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.
//go:build go1.17
// +build go1.17
package prometheus
import (
"math"
"runtime"
"runtime/metrics"
"sync"
//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
"github.com/golang/protobuf/proto"
"github.com/prometheus/client_golang/prometheus/internal"
dto "github.com/prometheus/client_model/go"
)
type goCollector struct {
base baseGoCollector
// rm... fields all pertain to the runtime/metrics package.
rmSampleBuf []metrics.Sample
rmSampleMap map[string]*metrics.Sample
rmMetrics []Metric
// With Go 1.17, the runtime/metrics package was introduced.
// From that point on, metric names produced by the runtime/metrics
// package could be generated from runtime/metrics names. However,
// these differ from the old names for the same values.
//
// This field exist to export the same values under the old names
// as well.
msMetrics memStatsMetrics
}
// NewGoCollector is the obsolete version of collectors.NewGoCollector.
// See there for documentation.
//
// Deprecated: Use collectors.NewGoCollector instead.
func NewGoCollector() Collector {
descriptions := metrics.All()
descMap := make(map[string]*metrics.Description)
for i := range descriptions {
descMap[descriptions[i].Name] = &descriptions[i]
}
// Generate a Desc and ValueType for each runtime/metrics metric.
metricSet := make([]Metric, 0, len(descriptions))
sampleBuf := make([]metrics.Sample, 0, len(descriptions))
sampleMap := make(map[string]*metrics.Sample, len(descriptions))
for i := range descriptions {
d := &descriptions[i]
namespace, subsystem, name, ok := internal.RuntimeMetricsToProm(d)
if !ok {
// Just ignore this metric; we can't do anything with it here.
// If a user decides to use the latest version of Go, we don't want
// to fail here. This condition is tested elsewhere.
continue
}
// Set up sample buffer for reading, and a map
// for quick lookup of sample values.
sampleBuf = append(sampleBuf, metrics.Sample{Name: d.Name})
sampleMap[d.Name] = &sampleBuf[len(sampleBuf)-1]
var m Metric
if d.Kind == metrics.KindFloat64Histogram {
_, hasSum := rmExactSumMap[d.Name]
m = newBatchHistogram(
NewDesc(
BuildFQName(namespace, subsystem, name),
d.Description,
nil,
nil,
),
hasSum,
)
} else if d.Cumulative {
m = NewCounter(CounterOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: name,
Help: d.Description,
})
} else {
m = NewGauge(GaugeOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: name,
Help: d.Description,
})
}
metricSet = append(metricSet, m)
}
return &goCollector{
base: newBaseGoCollector(),
rmSampleBuf: sampleBuf,
rmSampleMap: sampleMap,
rmMetrics: metricSet,
msMetrics: goRuntimeMemStats(),
}
}
// Describe returns all descriptions of the collector.
func (c *goCollector) Describe(ch chan<- *Desc) {
c.base.Describe(ch)
for _, i := range c.msMetrics {
ch <- i.desc
}
for _, m := range c.rmMetrics {
ch <- m.Desc()
}
}
// Collect returns the current state of all metrics of the collector.
func (c *goCollector) Collect(ch chan<- Metric) {
// Collect base non-memory metrics.
c.base.Collect(ch)
// Populate runtime/metrics sample buffer.
metrics.Read(c.rmSampleBuf)
for i, sample := range c.rmSampleBuf {
// N.B. switch on concrete type because it's significantly more efficient
// than checking for the Counter and Gauge interface implementations. In
// this case, we control all the types here.
switch m := c.rmMetrics[i].(type) {
case *counter:
// Guard against decreases. This should never happen, but a failure
// to do so will result in a panic, which is a harsh consequence for
// a metrics collection bug.
v0, v1 := m.get(), unwrapScalarRMValue(sample.Value)
if v1 > v0 {
m.Add(unwrapScalarRMValue(sample.Value) - m.get())
}
m.Collect(ch)
case *gauge:
m.Set(unwrapScalarRMValue(sample.Value))
m.Collect(ch)
case *batchHistogram:
m.update(sample.Value.Float64Histogram(), c.exactSumFor(sample.Name))
m.Collect(ch)
default:
panic("unexpected metric type")
}
}
// ms is a dummy MemStats that we populate ourselves so that we can
// populate the old metrics from it.
var ms runtime.MemStats
memStatsFromRM(&ms, c.rmSampleMap)
for _, i := range c.msMetrics {
ch <- MustNewConstMetric(i.desc, i.valType, i.eval(&ms))
}
}
// unwrapScalarRMValue unwraps a runtime/metrics value that is assumed
// to be scalar and returns the equivalent float64 value. Panics if the
// value is not scalar.
func unwrapScalarRMValue(v metrics.Value) float64 {
switch v.Kind() {
case metrics.KindUint64:
return float64(v.Uint64())
case metrics.KindFloat64:
return v.Float64()
case metrics.KindBad:
// Unsupported metric.
//
// This should never happen because we always populate our metric
// set from the runtime/metrics package.
panic("unexpected unsupported metric")
default:
// Unsupported metric kind.
//
// This should never happen because we check for this during initialization
// and flag and filter metrics whose kinds we don't understand.
panic("unexpected unsupported metric kind")
}
}
var rmExactSumMap = map[string]string{
"/gc/heap/allocs-by-size:bytes": "/gc/heap/allocs:bytes",
"/gc/heap/frees-by-size:bytes": "/gc/heap/frees:bytes",
}
// exactSumFor takes a runtime/metrics metric name (that is assumed to
// be of kind KindFloat64Histogram) and returns its exact sum and whether
// its exact sum exists.
//
// The runtime/metrics API for histograms doesn't currently expose exact
// sums, but some of the other metrics are in fact exact sums of histograms.
func (c *goCollector) exactSumFor(rmName string) float64 {
sumName, ok := rmExactSumMap[rmName]
if !ok {
return 0
}
s, ok := c.rmSampleMap[sumName]
if !ok {
return 0
}
return unwrapScalarRMValue(s.Value)
}
func memStatsFromRM(ms *runtime.MemStats, rm map[string]*metrics.Sample) {
lookupOrZero := func(name string) uint64 {
if s, ok := rm[name]; ok {
return s.Value.Uint64()
}
return 0
}
// Currently, MemStats adds tiny alloc count to both Mallocs AND Frees.
// The reason for this is because MemStats couldn't be extended at the time
// but there was a desire to have Mallocs at least be a little more representative,
// while having Mallocs - Frees still represent a live object count.
// Unfortunately, MemStats doesn't actually export a large allocation count,
// so it's impossible to pull this number out directly.
tinyAllocs := lookupOrZero("/gc/heap/tiny/allocs:objects")
ms.Mallocs = lookupOrZero("/gc/heap/allocs:objects") + tinyAllocs
ms.Frees = lookupOrZero("/gc/heap/frees:objects") + tinyAllocs
ms.TotalAlloc = lookupOrZero("/gc/heap/allocs:bytes")
ms.Sys = lookupOrZero("/memory/classes/total:bytes")
ms.Lookups = 0 // Already always zero.
ms.HeapAlloc = lookupOrZero("/memory/classes/heap/objects:bytes")
ms.Alloc = ms.HeapAlloc
ms.HeapInuse = ms.HeapAlloc + lookupOrZero("/memory/classes/heap/unused:bytes")
ms.HeapReleased = lookupOrZero("/memory/classes/heap/released:bytes")
ms.HeapIdle = ms.HeapReleased + lookupOrZero("/memory/classes/heap/free:bytes")
ms.HeapSys = ms.HeapInuse + ms.HeapIdle
ms.HeapObjects = lookupOrZero("/gc/heap/objects:objects")
ms.StackInuse = lookupOrZero("/memory/classes/heap/stacks:bytes")
ms.StackSys = ms.StackInuse + lookupOrZero("/memory/classes/os-stacks:bytes")
ms.MSpanInuse = lookupOrZero("/memory/classes/metadata/mspan/inuse:bytes")
ms.MSpanSys = ms.MSpanInuse + lookupOrZero("/memory/classes/metadata/mspan/free:bytes")
ms.MCacheInuse = lookupOrZero("/memory/classes/metadata/mcache/inuse:bytes")
ms.MCacheSys = ms.MCacheInuse + lookupOrZero("/memory/classes/metadata/mcache/free:bytes")
ms.BuckHashSys = lookupOrZero("/memory/classes/profiling/buckets:bytes")
ms.GCSys = lookupOrZero("/memory/classes/metadata/other:bytes")
ms.OtherSys = lookupOrZero("/memory/classes/other:bytes")
ms.NextGC = lookupOrZero("/gc/heap/goal:bytes")
// N.B. LastGC is omitted because runtime.GCStats already has this.
// See https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034
// for more details.
ms.LastGC = 0
// N.B. GCCPUFraction is intentionally omitted. This metric is not useful,
// and often misleading due to the fact that it's an average over the lifetime
// of the process.
// See https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034
// for more details.
ms.GCCPUFraction = 0
}
// batchHistogram is a mutable histogram that is updated
// in batches.
type batchHistogram struct {
selfCollector
// Static fields updated only once.
desc *Desc
hasSum bool
// Because this histogram operates in batches, it just uses a
// single mutex for everything. updates are always serialized
// but Write calls may operate concurrently with updates.
// Contention between these two sources should be rare.
mu sync.Mutex
buckets []float64 // Inclusive lower bounds.
counts []uint64
sum float64 // Used if hasSum is true.
}
func newBatchHistogram(desc *Desc, hasSum bool) *batchHistogram {
h := &batchHistogram{desc: desc, hasSum: hasSum}
h.init(h)
return h
}
// update updates the batchHistogram from a runtime/metrics histogram.
//
// sum must be provided if the batchHistogram was created to have an exact sum.
func (h *batchHistogram) update(his *metrics.Float64Histogram, sum float64) {
counts, buckets := his.Counts, his.Buckets
// Skip a -Inf bucket altogether. It's not clear how to represent that.
if math.IsInf(buckets[0], -1) {
buckets = buckets[1:]
counts = counts[1:]
}
h.mu.Lock()
defer h.mu.Unlock()
// Check if we're initialized.
if h.buckets == nil {
// Make copies of counts and buckets. It's really important
// that we don't retain his.Counts or his.Buckets anywhere since
// it's going to get reused.
h.buckets = make([]float64, len(buckets))
copy(h.buckets, buckets)
h.counts = make([]uint64, len(counts))
}
copy(h.counts, counts)
if h.hasSum {
h.sum = sum
}
}
func (h *batchHistogram) Desc() *Desc {
return h.desc
}
func (h *batchHistogram) Write(out *dto.Metric) error {
h.mu.Lock()
defer h.mu.Unlock()
sum := float64(0)
if h.hasSum {
sum = h.sum
}
dtoBuckets := make([]*dto.Bucket, 0, len(h.counts))
totalCount := uint64(0)
for i, count := range h.counts {
totalCount += count
if !h.hasSum {
// N.B. This computed sum is an underestimate.
sum += h.buckets[i] * float64(count)
}
// Skip the +Inf bucket, but only for the bucket list.
// It must still count for sum and totalCount.
if math.IsInf(h.buckets[i+1], 1) {
break
}
// Float64Histogram's upper bound is exclusive, so make it inclusive
// by obtaining the next float64 value down, in order.
upperBound := math.Nextafter(h.buckets[i+1], h.buckets[i])
dtoBuckets = append(dtoBuckets, &dto.Bucket{
CumulativeCount: proto.Uint64(totalCount),
UpperBound: proto.Float64(upperBound),
})
}
out.Histogram = &dto.Histogram{
Bucket: dtoBuckets,
SampleCount: proto.Uint64(totalCount),
SampleSum: proto.Float64(sum),
}
return nil
}

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// Copyright 2021 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.
//go:build go1.17
// +build go1.17
package prometheus
import (
"math"
"reflect"
"runtime"
"runtime/metrics"
"sync"
"testing"
"github.com/prometheus/client_golang/prometheus/internal"
dto "github.com/prometheus/client_model/go"
)
func TestGoCollectorRuntimeMetrics(t *testing.T) {
metrics := collectGoMetrics(t)
msChecklist := make(map[string]bool)
for _, m := range goRuntimeMemStats() {
msChecklist[m.desc.fqName] = false
}
if len(metrics) == 0 {
t.Fatal("no metrics created by Collect")
}
// Check a few specific metrics.
//
// Checking them all is somewhat pointless because the runtime/metrics
// metrics are going to shift underneath us. Also if we try to check
// against the runtime/metrics package in an automated fashion we're kind
// of missing the point, because we have to do all the same work the code
// has to do to perform the translation. Same for supporting old metric
// names (the best we can do here is make sure they're all accounted for).
var sysBytes, allocs float64
for _, m := range metrics {
name := m.Desc().fqName
switch name {
case "go_memory_classes_total_bytes":
checkMemoryMetric(t, m, &sysBytes)
case "go_sys_bytes":
checkMemoryMetric(t, m, &sysBytes)
case "go_gc_heap_allocs_bytes_total":
checkMemoryMetric(t, m, &allocs)
case "go_alloc_bytes_total":
checkMemoryMetric(t, m, &allocs)
}
if present, ok := msChecklist[name]; ok {
if present {
t.Errorf("memstats metric %s found more than once", name)
}
msChecklist[name] = true
}
}
for name := range msChecklist {
if present := msChecklist[name]; !present {
t.Errorf("memstats metric %s not collected", name)
}
}
}
func checkMemoryMetric(t *testing.T, m Metric, expValue *float64) {
t.Helper()
pb := &dto.Metric{}
m.Write(pb)
var value float64
if g := pb.GetGauge(); g != nil {
value = g.GetValue()
} else {
value = pb.GetCounter().GetValue()
}
if value <= 0 {
t.Error("bad value for total memory")
}
if *expValue == 0 {
*expValue = value
} else if value != *expValue {
t.Errorf("legacy metric and runtime/metrics metric do not match: want %d, got %d", int64(*expValue), int64(value))
}
}
var sink interface{}
func TestBatchHistogram(t *testing.T) {
goMetrics := collectGoMetrics(t)
var mhist Metric
for _, m := range goMetrics {
if m.Desc().fqName == "go_gc_heap_allocs_by_size_bytes_total" {
mhist = m
break
}
}
if mhist == nil {
t.Fatal("failed to find metric to test")
}
hist, ok := mhist.(*batchHistogram)
if !ok {
t.Fatal("found metric is not a runtime/metrics histogram")
}
// Make a bunch of allocations then do another collection.
//
// The runtime/metrics API tries to reuse memory where possible,
// so make sure that we didn't hang on to any of that memory in
// hist.
countsCopy := make([]uint64, len(hist.counts))
copy(countsCopy, hist.counts)
for i := 0; i < 100; i++ {
sink = make([]byte, 128)
}
collectGoMetrics(t)
for i, v := range hist.counts {
if v != countsCopy[i] {
t.Error("counts changed during new collection")
break
}
}
// Get the runtime/metrics copy.
s := []metrics.Sample{
{Name: "/gc/heap/allocs-by-size:bytes"},
}
metrics.Read(s)
rmHist := s[0].Value.Float64Histogram()
// runtime/metrics histograms always have -Inf and +Inf buckets.
// We never handle -Inf and +Inf is implicit.
wantBuckets := len(rmHist.Buckets) - 2
// Check to make sure the output proto makes sense.
pb := &dto.Metric{}
hist.Write(pb)
if math.IsInf(pb.Histogram.Bucket[len(pb.Histogram.Bucket)-1].GetUpperBound(), +1) {
t.Errorf("found +Inf bucket")
}
if got := len(pb.Histogram.Bucket); got != wantBuckets {
t.Errorf("got %d buckets in protobuf, want %d", got, wantBuckets)
}
for i, bucket := range pb.Histogram.Bucket {
// runtime/metrics histograms are lower-bound inclusive, but we're
// upper-bound inclusive. So just make sure the new inclusive upper
// bound is somewhere close by (in some cases it's equal).
wantBound := rmHist.Buckets[i+1]
if gotBound := *bucket.UpperBound; (wantBound-gotBound)/wantBound > 0.001 {
t.Errorf("got bound %f, want within 0.1%% of %f", gotBound, wantBound)
}
// Make sure counts are cumulative. Because of the consistency guarantees
// made by the runtime/metrics package, we're really not guaranteed to get
// anything even remotely the same here.
if i > 0 && *bucket.CumulativeCount < *pb.Histogram.Bucket[i-1].CumulativeCount {
t.Error("cumulative counts are non-monotonic")
}
}
}
func collectGoMetrics(t *testing.T) []Metric {
t.Helper()
c := NewGoCollector().(*goCollector)
// Collect all metrics.
ch := make(chan Metric)
var wg sync.WaitGroup
var metrics []Metric
wg.Add(1)
go func() {
defer wg.Done()
for metric := range ch {
metrics = append(metrics, metric)
}
}()
c.Collect(ch)
close(ch)
wg.Wait()
return metrics
}
func TestMemStatsEquivalence(t *testing.T) {
var msReal, msFake runtime.MemStats
descs := metrics.All()
samples := make([]metrics.Sample, len(descs))
samplesMap := make(map[string]*metrics.Sample)
for i := range descs {
samples[i].Name = descs[i].Name
samplesMap[descs[i].Name] = &samples[i]
}
// Force a GC cycle to try to reach a clean slate.
runtime.GC()
// Populate msReal.
runtime.ReadMemStats(&msReal)
// Populate msFake.
metrics.Read(samples)
memStatsFromRM(&msFake, samplesMap)
// Iterate over them and make sure they're somewhat close.
msRealValue := reflect.ValueOf(msReal)
msFakeValue := reflect.ValueOf(msFake)
typ := msRealValue.Type()
for i := 0; i < msRealValue.NumField(); i++ {
fr := msRealValue.Field(i)
ff := msFakeValue.Field(i)
switch typ.Kind() {
case reflect.Uint64:
// N.B. Almost all fields of MemStats are uint64s.
vr := fr.Interface().(uint64)
vf := ff.Interface().(uint64)
if float64(vr-vf)/float64(vf) > 0.05 {
t.Errorf("wrong value for %s: got %d, want %d", typ.Field(i).Name, vf, vr)
}
}
}
}
func TestExpectedRuntimeMetrics(t *testing.T) {
goMetrics := collectGoMetrics(t)
goMetricSet := make(map[string]Metric)
for _, m := range goMetrics {
goMetricSet[m.Desc().fqName] = m
}
descs := metrics.All()
rmSet := make(map[string]struct{})
for i := range descs {
rmName := descs[i].Name
rmSet[rmName] = struct{}{}
expFQName, ok := expectedRuntimeMetrics[rmName]
if !ok {
t.Errorf("found new runtime/metrics metric %s", rmName)
_, _, _, ok := internal.RuntimeMetricsToProm(&descs[i])
if !ok {
t.Errorf("new metric has name that can't be converted, or has an unsupported Kind")
}
continue
}
_, ok = goMetricSet[expFQName]
if !ok {
t.Errorf("existing runtime/metrics metric %s (expected fq name %s) not collected", rmName, expFQName)
continue
}
}
for rmName, fqName := range expectedRuntimeMetrics {
if _, ok := rmSet[rmName]; !ok {
t.Errorf("runtime/metrics metric %s removed", rmName)
continue
}
if _, ok := goMetricSet[fqName]; !ok {
t.Errorf("runtime/metrics metric %s not appearing under expected name %s", rmName, fqName)
continue
}
}
if t.Failed() {
t.Log("a new Go version may have been detected, please run")
t.Log("\tgo run gen_go_collector_metrics_set.go go1.X")
t.Log("where X is the Go version you are currently using")
}
}

39
prometheus/go_collector_metrics_go117_test.go Normal file
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@ -0,0 +1,39 @@
// Code generated by gen_go_collector_metrics_set.go; DO NOT EDIT.
//go:generate go run gen_go_collector_metrics_set.go go1.17
//go:build go1.17 && !go1.18
// +build go1.17,!go1.18
package prometheus
var expectedRuntimeMetrics = map[string]string{
"/gc/cycles/automatic:gc-cycles": "go_gc_cycles_automatic_gc_cycles_total",
"/gc/cycles/forced:gc-cycles": "go_gc_cycles_forced_gc_cycles_total",
"/gc/cycles/total:gc-cycles": "go_gc_cycles_total_gc_cycles_total",
"/gc/heap/allocs-by-size:bytes": "go_gc_heap_allocs_by_size_bytes_total",
"/gc/heap/allocs:bytes": "go_gc_heap_allocs_bytes_total",
"/gc/heap/allocs:objects": "go_gc_heap_allocs_objects_total",
"/gc/heap/frees-by-size:bytes": "go_gc_heap_frees_by_size_bytes_total",
"/gc/heap/frees:bytes": "go_gc_heap_frees_bytes_total",
"/gc/heap/frees:objects": "go_gc_heap_frees_objects_total",
"/gc/heap/goal:bytes": "go_gc_heap_goal_bytes",
"/gc/heap/objects:objects": "go_gc_heap_objects_objects",
"/gc/heap/tiny/allocs:objects": "go_gc_heap_tiny_allocs_objects_total",
"/gc/pauses:seconds": "go_gc_pauses_seconds_total",
"/memory/classes/heap/free:bytes": "go_memory_classes_heap_free_bytes",
"/memory/classes/heap/objects:bytes": "go_memory_classes_heap_objects_bytes",
"/memory/classes/heap/released:bytes": "go_memory_classes_heap_released_bytes",
"/memory/classes/heap/stacks:bytes": "go_memory_classes_heap_stacks_bytes",
"/memory/classes/heap/unused:bytes": "go_memory_classes_heap_unused_bytes",
"/memory/classes/metadata/mcache/free:bytes": "go_memory_classes_metadata_mcache_free_bytes",
"/memory/classes/metadata/mcache/inuse:bytes": "go_memory_classes_metadata_mcache_inuse_bytes",
"/memory/classes/metadata/mspan/free:bytes": "go_memory_classes_metadata_mspan_free_bytes",
"/memory/classes/metadata/mspan/inuse:bytes": "go_memory_classes_metadata_mspan_inuse_bytes",
"/memory/classes/metadata/other:bytes": "go_memory_classes_metadata_other_bytes",
"/memory/classes/os-stacks:bytes": "go_memory_classes_os_stacks_bytes",
"/memory/classes/other:bytes": "go_memory_classes_other_bytes",
"/memory/classes/profiling/buckets:bytes": "go_memory_classes_profiling_buckets_bytes",
"/memory/classes/total:bytes": "go_memory_classes_total_bytes",
"/sched/goroutines:goroutines": "go_sched_goroutines_goroutines",
"/sched/latencies:seconds": "go_sched_latencies_seconds",
}

93
prometheus/go_collector_test.go
View File

@ -154,96 +154,3 @@ func TestGoCollectorGC(t *testing.T) {
break
}
}
func TestGoCollectorMemStats(t *testing.T) {
var (
c = NewGoCollector().(*goCollector)
got uint64
)
checkCollect := func(want uint64) {
metricCh := make(chan Metric)
endCh := make(chan struct{})
go func() {
c.Collect(metricCh)
close(endCh)
}()
Collect:
for {
select {
case metric := <-metricCh:
if metric.Desc().fqName != "go_memstats_alloc_bytes" {
continue Collect
}
pb := &dto.Metric{}
metric.Write(pb)
got = uint64(pb.GetGauge().GetValue())
case <-endCh:
break Collect
}
}
if want != got {
t.Errorf("unexpected value of go_memstats_alloc_bytes, want %d, got %d", want, got)
}
}
// Speed up the timing to make the test faster.
c.msMaxWait = 5 * time.Millisecond
c.msMaxAge = 50 * time.Millisecond
// Scenario 1: msRead responds slowly, no previous memstats available,
// msRead is executed anyway.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 1
}
checkCollect(1)
// Now msLast is set.
c.msMtx.Lock()
if want, got := uint64(1), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 2: msRead responds fast, previous memstats available, new
// value collected.
c.msRead = func(ms *runtime.MemStats) {
ms.Alloc = 2
}
checkCollect(2)
// msLast is set, too.
c.msMtx.Lock()
if want, got := uint64(2), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 3: msRead responds slowly, previous memstats available, old
// value collected.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 3
}
checkCollect(2)
// After waiting, new value is still set in msLast.
time.Sleep(80 * time.Millisecond)
c.msMtx.Lock()
if want, got := uint64(3), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
// Scenario 4: msRead responds slowly, previous memstats is too old, new
// value collected.
c.msRead = func(ms *runtime.MemStats) {
time.Sleep(20 * time.Millisecond)
ms.Alloc = 4
}
checkCollect(4)
c.msMtx.Lock()
if want, got := uint64(4), c.msLast.Alloc; want != got {
t.Errorf("unexpected of msLast.Alloc, want %d, got %d", want, got)
}
c.msMtx.Unlock()
}

77
prometheus/internal/go_runtime_metrics.go Normal file
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@ -0,0 +1,77 @@
// Copyright 2021 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.
//go:build go1.17
// +build go1.17
package internal
import (
"path"
"runtime/metrics"
"strings"
"github.com/prometheus/common/model"
)
// RuntimeMetricsToProm produces a Prometheus metric name from a runtime/metrics
// metric description and validates whether the metric is suitable for integration
// with Prometheus.
//
// Returns false if a name could not be produced, or if Prometheus does not understand
// the runtime/metrics Kind.
//
// Note that the main reason a name couldn't be produced is if the runtime/metrics
// package exports a name with characters outside the valid Prometheus metric name
// character set. This is theoretically possible, but should never happen in practice.
// Still, don't rely on it.
func RuntimeMetricsToProm(d *metrics.Description) (string, string, string, bool) {
namespace := "go"
comp := strings.SplitN(d.Name, ":", 2)
key := comp[0]
unit := comp[1]
// The last path element in the key is the name,
// the rest is the subsystem.
subsystem := path.Dir(key[1:] /* remove leading / */)
name := path.Base(key)
// subsystem is translated by replacing all / and - with _.
subsystem = strings.ReplaceAll(subsystem, "/", "_")
subsystem = strings.ReplaceAll(subsystem, "-", "_")
// unit is translated assuming that the unit contains no
// non-ASCII characters.
unit = strings.ReplaceAll(unit, "-", "_")
unit = strings.ReplaceAll(unit, "*", "_")
unit = strings.ReplaceAll(unit, "/", "_per_")
// name has - replaced with _ and is concatenated with the unit and
// other data.
name = strings.ReplaceAll(name, "-", "_")
name = name + "_" + unit
if d.Cumulative {
name = name + "_total"
}
valid := model.IsValidMetricName(model.LabelValue(namespace + "_" + subsystem + "_" + name))
switch d.Kind {
case metrics.KindUint64:
case metrics.KindFloat64:
case metrics.KindFloat64Histogram:
default:
valid = false
}
return namespace, subsystem, name, valid
}

97
prometheus/internal/go_runtime_metrics_test.go Normal file
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@ -0,0 +1,97 @@
// Copyright 2021 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.
//go:build go1.17
// +build go1.17
package internal
import (
"runtime/metrics"
"testing"
)
func TestRuntimeMetricsToProm(t *testing.T) {
tests := []struct {
got metrics.Description
expect string
}{
{
metrics.Description{
Name: "/memory/live:bytes",
Kind: metrics.KindUint64,
},
"go_memory_live_bytes",
},
{
metrics.Description{
Name: "/memory/allocs:bytes",
Kind: metrics.KindUint64,
Cumulative: true,
},
"go_memory_allocs_bytes_total",
},
{
metrics.Description{
Name: "/memory/alloc-rate:bytes/second",
Kind: metrics.KindFloat64,
},
"go_memory_alloc_rate_bytes_per_second",
},
{
metrics.Description{
Name: "/gc/time:cpu*seconds",
Kind: metrics.KindFloat64,
Cumulative: true,
},
"go_gc_time_cpu_seconds_total",
},
{
metrics.Description{
Name: "/this/is/a/very/deep/metric:metrics",
Kind: metrics.KindFloat64,
},
"go_this_is_a_very_deep_metric_metrics",
},
{
metrics.Description{
Name: "/this*is*an*invalid...:µname",
Kind: metrics.KindUint64,
},
"",
},
{
metrics.Description{
Name: "/this/is/a/valid/name:objects",
Kind: metrics.KindBad,
},
"",
},
}
for _, test := range tests {
ns, ss, n, ok := RuntimeMetricsToProm(&test.got)
name := ns + "_" + ss + "_" + n
if test.expect == "" && ok {
t.Errorf("bad input expected a bad output: input %s, got %s", test.got.Name, name)
continue
}
if test.expect != "" && !ok {
t.Errorf("unexpected bad output on good input: input %s", test.got.Name)
continue
}
if test.expect != "" && name != test.expect {
t.Errorf("expected %s, got %s", test.expect, name)
continue
}
}
}