feat: add automatic GOMAXPROCS to admission webhook

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

cmd/admission-webhook/main.go

@@ -31,6 +31,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"golang.org/x/sync/errgroup"
 
+	"github.com/prometheus-operator/prometheus-operator/internal/goruntime"
 	logging "github.com/prometheus-operator/prometheus-operator/internal/log"
 	"github.com/prometheus-operator/prometheus-operator/pkg/admission"
 	"github.com/prometheus-operator/prometheus-operator/pkg/server"
@@ -60,6 +61,8 @@ func main() {
 		stdlog.Fatal(err)
 	}
 
+	goruntime.SetMaxProcs(logger)
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	wg, ctx := errgroup.WithContext(ctx)

cmd/operator/main.go

@@ -24,7 +24,6 @@ import (
 	"os"
 	"os/signal"
 	"regexp"
-	"strings"
 	"syscall"
 
 	"github.com/go-kit/log"
@@ -34,7 +33,6 @@ import (
 	versioncollector "github.com/prometheus/client_golang/prometheus/collectors/version"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/prometheus/common/version"
-	"go.uber.org/automaxprocs/maxprocs"
 	"golang.org/x/sync/errgroup"
 	corev1 "k8s.io/api/core/v1"
 	storagev1 "k8s.io/api/storage/v1"
@@ -44,6 +42,7 @@ import (
 	k8sflag "k8s.io/component-base/cli/flag"
 	"k8s.io/utils/ptr"
 
+	"github.com/prometheus-operator/prometheus-operator/internal/goruntime"
 	logging "github.com/prometheus-operator/prometheus-operator/internal/log"
 	"github.com/prometheus-operator/prometheus-operator/pkg/admission"
 	alertmanagercontroller "github.com/prometheus-operator/prometheus-operator/pkg/alertmanager"
@@ -195,13 +194,6 @@ func run(fs *flag.FlagSet) int {
 		stdlog.Fatal(err)
 	}
 
-	l := func(format string, a ...interface{}) {
-		level.Info(logger).Log("component", "automaxprocs", "msg", fmt.Sprintf(strings.TrimPrefix(format, "maxprocs: "), a...))
-	}
-	if _, err := maxprocs.Set(maxprocs.Logger(l)); err != nil {
-		level.Warn(logger).Log("msg", "Failed to set GOMAXPROCS automatically", "err", err)
-	}
-
 	gates, err := operator.ValidateFeatureGates(featureGates)
 	if err != nil {
 		level.Error(logger).Log(
@@ -213,6 +205,7 @@ func run(fs *flag.FlagSet) int {
 	level.Info(logger).Log("msg", "Starting Prometheus Operator", "version", version.Info())
 	level.Info(logger).Log("build_context", version.BuildContext())
 	level.Info(logger).Log("feature_gates", gates)
+	goruntime.SetMaxProcs(logger)
 
 	if len(cfg.Namespaces.AllowList) > 0 && len(cfg.Namespaces.DenyList) > 0 {
 		level.Error(logger).Log(

cmd/prometheus-config-reloader/main.go

@@ -37,8 +37,8 @@ import (
 	"github.com/prometheus/common/version"
 	"github.com/prometheus/exporter-toolkit/web"
 	"github.com/thanos-io/thanos/pkg/reloader"
-	"go.uber.org/automaxprocs/maxprocs"
 
+	"github.com/prometheus-operator/prometheus-operator/internal/goruntime"
 	logging "github.com/prometheus-operator/prometheus-operator/internal/log"
 	"github.com/prometheus-operator/prometheus-operator/pkg/operator"
 	"github.com/prometheus-operator/prometheus-operator/pkg/versionutil"
@@ -123,13 +123,6 @@ func main() {
 		stdlog.Fatal(err)
 	}
 
-	l := func(format string, a ...interface{}) {
-		level.Info(logger).Log("component", "automaxprocs", "msg", fmt.Sprintf(strings.TrimPrefix(format, "maxprocs: "), a...))
-	}
-	if _, err := maxprocs.Set(maxprocs.Logger(l)); err != nil {
-		level.Warn(logger).Log("msg", "Failed to set GOMAXPROCS automatically", "err", err)
-	}
-
 	err = web.Validate(*webConfig)
 	if err != nil {
 		level.Error(logger).Log("msg", "Unable to validate web configuration file", "err", err)
@@ -144,6 +137,7 @@ func main() {
 
 	level.Info(logger).Log("msg", "Starting prometheus-config-reloader", "version", version.Info())
 	level.Info(logger).Log("build_context", version.BuildContext())
+	goruntime.SetMaxProcs(logger)
 
 	r := prometheus.NewRegistry()
 	r.MustRegister(

internal/goruntime/cpu.go

@@ -0,0 +1,34 @@
+// Copyright 2024 The prometheus-operator 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 goruntime
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
+	"go.uber.org/automaxprocs/maxprocs"
+)
+
+func SetMaxProcs(logger log.Logger) {
+	l := func(format string, a ...interface{}) {
+		level.Info(logger).Log("msg", fmt.Sprintf(strings.TrimPrefix(format, "maxprocs: "), a...))
+	}
+
+	if _, err := maxprocs.Set(maxprocs.Logger(l)); err != nil {
+		level.Warn(logger).Log("msg", "Failed to set GOMAXPROCS automatically", "err", err)
+	}
+}