prometheus: Fix convention violating names for generated collector metrics (#1048)

* Fix convention violating names for generated collector metrics

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

* Add new Go collector example

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

.gitignore

@@ -1,6 +1,7 @@
 # Examples
 examples/simple/simple
 examples/random/random
+examples/gocollector/gocollector
 
 # Typical backup/temporary files of editors
 *~

CHANGELOG.md

@@ -3,6 +3,7 @@
 * [CHANGE] Minimum required Go version is now 1.16.
 * [CHANGE] Added `collectors.WithGoCollections` that allows to choose what collection of Go runtime metrics user wants: Equivalent of [`MemStats` structure](https://pkg.go.dev/runtime#MemStats) configured using `GoRuntimeMemStatsCollection`, new based on dedicated [runtime/metrics](https://pkg.go.dev/runtime/metrics) metrics represented by `GoRuntimeMetricsCollection` option, or both by specifying `GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection` flag.
 * [CHANGE] :warning: Change in `collectors.NewGoCollector` metrics: Reverting addition of new ~80 runtime metrics by default. You can enable this back with `GoRuntimeMetricsCollection` option or `GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection`  for smooth transition.
+* [BUGFIX] Fix the bug that causes generated histogram metric names to end with `_total`. `go_gc_heap_allocs_by_size_bytes_total` -> `go_gc_heap_allocs_by_size_bytes`, `go_gc_heap_frees_by_size_bytes_total` -> `go_gc_heap_allocs_by_size_bytes` and`go_gc_pauses_seconds_total` -> `go_gc_pauses_seconds`.
 
 ## 1.12.1 / 2022-01-29
 

Dockerfile

@@ -21,11 +21,14 @@ WORKDIR /go/src/github.com/prometheus/client_golang/examples/random
 RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'
 WORKDIR /go/src/github.com/prometheus/client_golang/examples/simple
 RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'
+WORKDIR /go/src/github.com/prometheus/client_golang/examples/gocollector
+RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'
 
 # Final image.
 FROM quay.io/prometheus/busybox:latest
 LABEL maintainer="The Prometheus Authors <prometheus-developers@googlegroups.com>"
 COPY --from=builder /go/src/github.com/prometheus/client_golang/examples/random \
-    /go/src/github.com/prometheus/client_golang/examples/simple ./
+    /go/src/github.com/prometheus/client_golang/examples/simple \
+    /go/src/github.com/prometheus/client_golang/examples/gocollector ./
 EXPOSE 8080
-CMD ["echo", "Please run an example. Either /random or /simple"]
+CMD ["echo", "Please run an example. Either /random, /simple or /gocollector"]

examples/gocollector/main.go

@@ -0,0 +1,55 @@
+// Copyright 2022 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
+
+// A minimal example of how to include Prometheus instrumentation.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var addr = flag.String("listen-address", ":8080", "The address to listen on for HTTP requests.")
+
+func main() {
+	flag.Parse()
+
+	// Create a new registry.
+	reg := prometheus.NewRegistry()
+
+	// Add Go module build info.
+	reg.MustRegister(collectors.NewBuildInfoCollector())
+	reg.MustRegister(collectors.NewGoCollector(
+		collectors.WithGoCollections(collectors.GoRuntimeMemStatsCollection | collectors.GoRuntimeMetricsCollection),
+	))
+
+	// Expose the registered metrics via HTTP.
+	http.Handle("/metrics", promhttp.HandlerFor(
+		reg,
+		promhttp.HandlerOpts{
+			// Opt into OpenMetrics to support exemplars.
+			EnableOpenMetrics: true,
+		},
+	))
+	fmt.Println("Hello world from new Go Collector!")
+	log.Fatal(http.ListenAndServe(*addr, nil))
+}

prometheus/collectors/go_collector_latest.go

@@ -72,9 +72,9 @@ const (
 //
 // The current default is GoRuntimeMemStatsCollection, so the compatibility mode with
 // client_golang pre v1.12 (move to runtime/metrics).
-func WithGoCollections(flags uint32) goOption {
+func WithGoCollections(flags GoCollectionOption) goOption {
 	return func(o *goOptions) {
-		o.EnabledCollections = flags
+		o.EnabledCollections = uint32(flags)
 	}
 }
 

prometheus/gen_go_collector_metrics_set.go

@@ -39,11 +39,11 @@ func main() {
 	}
 	toolVersion := runtime.Version()
 	mtv := majorVersion(toolVersion)
-	mv != majorVersion(os.Args[1])
+	mv := majorVersion(os.Args[1])
 	if mtv != mv {
 		log.Fatalf("using Go version %q but expected Go version %q", mtv, mv)
 	}
-	version, err := parseVersion(os.Args[1])
+	version, err := parseVersion(mv)
 	if err != nil {
 		log.Fatalf("parsing Go version: %v", err)
 	}

prometheus/go_collector_latest_test.go

@@ -24,8 +24,9 @@ import (
 	"sync"
 	"testing"
 
-	"github.com/prometheus/client_golang/prometheus/internal"
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus/internal"
 )
 
 func TestRmForMemStats(t *testing.T) {
@@ -121,7 +122,7 @@ func TestBatchHistogram(t *testing.T) {
 
 	var mhist Metric
 	for _, m := range goMetrics {
-		if m.Desc().fqName == "go_gc_heap_allocs_by_size_bytes_total" {
+		if m.Desc().fqName == "go_gc_heap_allocs_by_size_bytes" {
 			mhist = m
 			break
 		}

prometheus/go_collector_metrics_go117_test.go

@@ -10,16 +10,16 @@ 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-by-size:bytes":               "go_gc_heap_allocs_by_size_bytes",
 	"/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-by-size:bytes":                "go_gc_heap_frees_by_size_bytes",
 	"/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",
+	"/gc/pauses:seconds":                          "go_gc_pauses_seconds",
 	"/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",

prometheus/go_collector_metrics_go118_test.go

@@ -10,16 +10,16 @@ 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-by-size:bytes":               "go_gc_heap_allocs_by_size_bytes",
 	"/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-by-size:bytes":                "go_gc_heap_frees_by_size_bytes",
 	"/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",
+	"/gc/pauses:seconds":                          "go_gc_pauses_seconds",
 	"/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",

prometheus/internal/go_runtime_metrics.go

@@ -62,7 +62,7 @@ func RuntimeMetricsToProm(d *metrics.Description) (string, string, string, bool)
 	// other data.
 	name = strings.ReplaceAll(name, "-", "_")
 	name = name + "_" + unit
-	if d.Cumulative {
+	if d.Cumulative && d.Kind != metrics.KindFloat64Histogram {
 		name = name + "_total"
 	}
 
@@ -84,12 +84,12 @@ func RuntimeMetricsToProm(d *metrics.Description) (string, string, string, bool)
 func RuntimeMetricsBucketsForUnit(buckets []float64, unit string) []float64 {
 	switch unit {
 	case "bytes":
-		// Rebucket as powers of 2.
+		// Re-bucket as powers of 2.
-		return rebucketExp(buckets, 2)
+		return reBucketExp(buckets, 2)
 	case "seconds":
-		// Rebucket as powers of 10 and then merge all buckets greater
+		// Re-bucket as powers of 10 and then merge all buckets greater
 		// than 1 second into the +Inf bucket.
-		b := rebucketExp(buckets, 10)
+		b := reBucketExp(buckets, 10)
 		for i := range b {
 			if b[i] <= 1 {
 				continue
@@ -103,11 +103,11 @@ func RuntimeMetricsBucketsForUnit(buckets []float64, unit string) []float64 {
 	return buckets
 }
 
-// rebucketExp takes a list of bucket boundaries (lower bound inclusive) and
+// reBucketExp takes a list of bucket boundaries (lower bound inclusive) and
 // downsamples the buckets to those a multiple of base apart. The end result
 // is a roughly exponential (in many cases, perfectly exponential) bucketing
 // scheme.
-func rebucketExp(buckets []float64, base float64) []float64 {
+func reBucketExp(buckets []float64, base float64) []float64 {
 	bucket := buckets[0]
 	var newBuckets []float64
 	// We may see a -Inf here, in which case, add it and skip it