/
gen_go_collector_metrics_set.go
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/
gen_go_collector_metrics_set.go
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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 ignore
//go:build ignore
// +build ignore
package main
import (
"bytes"
"fmt"
"go/format"
"log"
"math"
"os"
"runtime"
"runtime/metrics"
"strings"
"text/template"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/internal"
"github.com/hashicorp/go-version"
)
func main() {
var givenVersion string
toolVersion := runtime.Version()
if len(os.Args) != 2 {
log.Printf("requires Go version (e.g. go1.17) as an argument. Since it is not specified, assuming %s.", toolVersion)
givenVersion = toolVersion
} else {
givenVersion = os.Args[1]
}
log.Printf("given version for Go: %s", givenVersion)
log.Printf("tool version for Go: %s", toolVersion)
tv, err := version.NewVersion(strings.TrimPrefix(givenVersion, "go"))
if err != nil {
log.Fatal(err)
}
gv, err := version.NewVersion(strings.TrimPrefix(toolVersion, "go"))
if err != nil {
log.Fatal(err)
}
if !gv.Equal(tv) {
log.Fatalf("using Go version %q but expected Go version %q", tv, gv)
}
v := goVersion(gv.Segments()[1])
log.Printf("generating metrics for Go version %q", v)
// Generate code.
var buf bytes.Buffer
err = testFile.Execute(&buf, struct {
Descriptions []metrics.Description
GoVersion goVersion
Cardinality int
}{
Descriptions: metrics.All(),
GoVersion: v,
Cardinality: rmCardinality(),
})
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", v.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 rmCardinality() int {
cardinality := 0
// Collect all histogram samples so that we can get their buckets.
// The API guarantees that the buckets are always fixed for the lifetime
// of the process.
var histograms []metrics.Sample
for _, d := range metrics.All() {
if d.Kind == metrics.KindFloat64Histogram {
histograms = append(histograms, metrics.Sample{Name: d.Name})
} else {
cardinality++
}
}
// Handle histograms.
metrics.Read(histograms)
for i := range histograms {
name := histograms[i].Name
buckets := internal.RuntimeMetricsBucketsForUnit(
histograms[i].Value.Float64Histogram().Buckets,
name[strings.IndexRune(name, ':')+1:],
)
cardinality += len(buckets) + 3 // Plus total count, sum, and the implicit infinity bucket.
// runtime/metrics bucket boundaries are lower-bound-inclusive, but
// always represents each actual *boundary* so Buckets is always
// 1 longer than Counts, while in Prometheus the mapping is one-to-one,
// as the bottom bucket extends to -Inf, and the top infinity bucket is
// implicit. Therefore, we should have one fewer bucket than is listed
// above.
cardinality--
if buckets[len(buckets)-1] == math.Inf(1) {
// We already counted the infinity bucket separately.
cardinality--
}
// https://github.com/prometheus/client_golang/pull/1049/files
if buckets[0] == math.Inf(-1) {
// We already counted the infinity bucket separately.
cardinality--
}
}
return cardinality
}
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}}
}
const expectedRuntimeMetricsCardinality = {{.Cardinality}}
`))