gocollector: Reverted client_golang v1.12 addition of runtime/metrics metrics by default. (#1033)

Fixes #967

Signed-off-by: Bartlomiej Plotka <[email protected]>

Author: bwplotka

CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+* [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.
+
 ## 1.12.1 / 2022-01-29
 
 * [BUGFIX] Make the Go 1.17 collector concurrency-safe #969

prometheus/collectors/go_collector_latest.go

@@ -70,8 +70,8 @@ const (
 // WithGoCollections(GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection) means both GoRuntimeMemStatsCollection
 // metrics and GoRuntimeMetricsCollection will be exposed.
 //
-// Use WithGoCollections(GoRuntimeMemStatsCollection) to have Go collector working in
-// the compatibility mode with client_golang pre v1.12 (move to runtime/metrics).
+// The current default is GoRuntimeMemStatsCollection, so the compatibility mode with
+// client_golang pre v1.12 (move to runtime/metrics).
 func WithGoCollections(flags uint32) goOption {
 	return func(o *goOptions) {
 		o.EnabledCollections = flags

prometheus/go_collector_latest.go

@@ -132,7 +132,7 @@ func (c GoCollectorOptions) isEnabled(flag uint32) bool {
 	return c.EnabledCollections&flag != 0
 }
 
-const defaultGoCollections = goRuntimeMemStatsCollection | goRuntimeMetricsCollection
+const defaultGoCollections = goRuntimeMemStatsCollection
 
 // NewGoCollector is the obsolete version of collectors.NewGoCollector.
 // See there for documentation.

prometheus/go_collector_latest_test.go

@@ -117,7 +117,7 @@ func TestGoCollector(t *testing.T) {
 var sink interface{}
 
 func TestBatchHistogram(t *testing.T) {
-	goMetrics := collectGoMetrics(t, defaultGoCollections)
+	goMetrics := collectGoMetrics(t, goRuntimeMetricsCollection)
 
 	var mhist Metric
 	for _, m := range goMetrics {