Add crd metrics usage information

Signed-off-by: Ruben Vargas <ruben.vp8510@gmail.com>

apis/v1beta1/collector_webhook.go

@@ -166,23 +166,66 @@ func (c CollectorWebhook) ValidateCreate(ctx context.Context, obj runtime.Object
 	if !ok {
 		return nil, fmt.Errorf("expected an OpenTelemetryCollector, received %T", obj)
 	}
-	return c.validate(ctx, otelcol)
+
+	warnings, err := c.validate(ctx, otelcol)
+	if err != nil {
+		return warnings, err
+	}
+
+	err = IncCounters(ctx, otelcol)
+	if err != nil {
+		return warnings, err
+	}
+
+	return warnings, nil
 }
 
-func (c CollectorWebhook) ValidateUpdate(ctx context.Context, _, newObj runtime.Object) (admission.Warnings, error) {
+func (c CollectorWebhook) ValidateUpdate(ctx context.Context, oldObj, newObj runtime.Object) (admission.Warnings, error) {
 	otelcol, ok := newObj.(*OpenTelemetryCollector)
 	if !ok {
 		return nil, fmt.Errorf("expected an OpenTelemetryCollector, received %T", newObj)
 	}
-	return c.validate(ctx, otelcol)
+
+	otelcolOld, ok := oldObj.(*OpenTelemetryCollector)
+	if !ok {
+		return nil, fmt.Errorf("expected an OpenTelemetryCollector, received %T", oldObj)
+	}
+
+	warnings, err := c.validate(ctx, otelcol)
+	if err != nil {
+		return warnings, err
+	}
+
+	// Decrease all metrics related to old CR
+	err = DecCounters(ctx, otelcolOld)
+	if err != nil {
+		return warnings, err
+	}
+
+	// Increase all metrics related to new CR
+	err = IncCounters(ctx, otelcolOld)
+	if err != nil {
+		return warnings, err
+	}
+	return warnings, nil
 }
 
 func (c CollectorWebhook) ValidateDelete(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
 	otelcol, ok := obj.(*OpenTelemetryCollector)
 	if !ok || otelcol == nil {
 		return nil, fmt.Errorf("expected an OpenTelemetryCollector, received %T", obj)
 	}
-	return c.validate(ctx, otelcol)
+
+	warnings, err := c.validate(ctx, otelcol)
+	if err != nil {
+		return warnings, err
+	}
+	err = DecCounters(ctx, otelcol)
+	if err != nil {
+		return warnings, err
+	}
+
+	return warnings, nil
 }
 
 func (c CollectorWebhook) validate(ctx context.Context, r *OpenTelemetryCollector) (admission.Warnings, error) {

apis/v1beta1/metrics.go

@@ -0,0 +1,149 @@
+// Copyright The OpenTelemetry 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 v1beta1
+
+import (
+	"context"
+	"strings"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/exporters/prometheus"
+	"go.opentelemetry.io/otel/metric"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+)
+
+const (
+	meterName = "crd-metrics"
+)
+
+// Metric labels
+
+const (
+	prefix     = "opentelemetry_collector_"
+	receivers  = prefix + "receivers"
+	exporters  = prefix + "exporters"
+	processors = prefix + "processors"
+	extensions = prefix + "extensions"
+	mode       = prefix + "info"
+)
+
+type components struct {
+	receivers  []string
+	processors []string
+	exporters  []string
+	extensions []string
+}
+
+// BootstrapMetrics configures the OpenTelemetry meter provider with the Prometheus exporter.
+func BootstrapMetrics() error {
+
+	exporter, err := prometheus.New(prometheus.WithRegisterer(metrics.Registry))
+	if err != nil {
+		return err
+	}
+	provider := sdkmetric.NewMeterProvider(sdkmetric.WithReader(exporter))
+	otel.SetMeterProvider(provider)
+	return err
+}
+
+func extractElements(elements map[string]interface{}) []string {
+	if elements == nil {
+		return []string{}
+	}
+
+	itemsMap := map[string]struct{}{}
+	var items []string
+	for key := range elements {
+		itemName := strings.SplitN(key, "/", 2)[0]
+		itemsMap[itemName] = struct{}{}
+	}
+	for key := range itemsMap {
+		items = append(items, key)
+	}
+	return items
+}
+
+func getComponentsFromConfigV1Beta1(yamlContent Config) *components {
+
+	info := &components{
+		receivers: extractElements(yamlContent.Receivers.Object),
+		exporters: extractElements(yamlContent.Exporters.Object),
+	}
+
+	if yamlContent.Processors != nil {
+		info.processors = extractElements(yamlContent.Processors.Object)
+	}
+
+	if yamlContent.Extensions != nil {
+		info.extensions = extractElements(yamlContent.Extensions.Object)
+	}
+	return info
+}
+
+func IncCounters(ctx context.Context, collector *OpenTelemetryCollector) error {
+	return updateCounter(ctx, collector, true)
+}
+
+func DecCounters(ctx context.Context, collector *OpenTelemetryCollector) error {
+	return updateCounter(ctx, collector, false)
+}
+
+func updateCounter(ctx context.Context, collector *OpenTelemetryCollector, up bool) error {
+	meter := otel.Meter(meterName)
+	receiversCounter, err := meter.Int64UpDownCounter(receivers)
+	if err != nil {
+		return err
+	}
+
+	exporterCounter, err := meter.Int64UpDownCounter(exporters)
+	if err != nil {
+		return err
+	}
+
+	processorCounter, err := meter.Int64UpDownCounter(processors)
+	if err != nil {
+		return err
+	}
+
+	extensionsCounter, err := meter.Int64UpDownCounter(extensions)
+	if err != nil {
+		return err
+	}
+
+	components := getComponentsFromConfigV1Beta1(collector.Spec.Config)
+	moveCounter(ctx, collector, components.receivers, receiversCounter, up)
+	moveCounter(ctx, collector, components.exporters, exporterCounter, up)
+	moveCounter(ctx, collector, components.processors, processorCounter, up)
+	moveCounter(ctx, collector, components.extensions, extensionsCounter, up)
+
+	return nil
+}
+
+func moveCounter(
+	ctx context.Context, collector *OpenTelemetryCollector, types []string, upDown metric.Int64UpDownCounter, up bool) {
+	for _, exporter := range types {
+		inc := 1
+		if !up {
+			inc = -1
+		}
+		upDown.Add(ctx, int64(inc), metric.WithAttributes(
+			attribute.Key("collector_name").String(collector.Name),
+			attribute.Key("namespace").String(collector.Namespace),
+			attribute.Key("type").String(exporter),
+		))
+	}
+}

config/manager/kustomization.yaml

@@ -1,2 +1,8 @@
 resources:
 - manager.yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+images:
+- name: controller
+  newName: quay.io/rvargasp/opentelemetry-operator
+  newTag: 1714976402.0.0

go.mod

@@ -190,6 +190,7 @@ require (
 	go.mongodb.org/mongo-driver v1.14.0 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
+	go.opentelemetry.io/otel/exporters/prometheus v0.48.0 // indirect
 	go.opentelemetry.io/otel/trace v1.26.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.2.0 // indirect
 	go.uber.org/atomic v1.11.0 // indirect

go.sum

@@ -645,6 +645,8 @@ go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.24.0 h1:t6wl9SPayj+c7lEIFgm
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.24.0/go.mod h1:iSDOcsnSA5INXzZtwaBPrKp/lWu/V14Dd+llD0oI2EA=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.24.0 h1:Xw8U6u2f8DK2XAkGRFV7BBLENgnTGX9i4rQRxJf+/vs=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.24.0/go.mod h1:6KW1Fm6R/s6Z3PGXwSJN2K4eT6wQB3vXX6CVnYX9NmM=
+go.opentelemetry.io/otel/exporters/prometheus v0.48.0 h1:sBQe3VNGUjY9IKWQC6z2lNqa5iGbDSxhs60ABwK4y0s=
+go.opentelemetry.io/otel/exporters/prometheus v0.48.0/go.mod h1:DtrbMzoZWwQHyrQmCfLam5DZbnmorsGbOtTbYHycU5o=
 go.opentelemetry.io/otel/metric v1.26.0 h1:7S39CLuY5Jgg9CrnA9HHiEjGMF/X2VHvoXGgSllRz30=
 go.opentelemetry.io/otel/metric v1.26.0/go.mod h1:SY+rHOI4cEawI9a7N1A4nIg/nTQXe1ccCNWYOJUrpX4=
 go.opentelemetry.io/otel/sdk v1.26.0 h1:Y7bumHf5tAiDlRYFmGqetNcLaVUZmh4iYfmGxtmz7F8=

main.go

@@ -118,6 +118,7 @@ func main() {
 		enableNginxInstrumentation       bool
 		enableNodeJSInstrumentation      bool
 		enableJavaInstrumentation        bool
+		enableCRMetrics                  bool
 		collectorImage                   string
 		targetAllocatorImage             string
 		operatorOpAMPBridgeImage         string
@@ -149,6 +150,8 @@ func main() {
 	pflag.BoolVar(&enableNginxInstrumentation, constants.FlagNginx, false, "Controls whether the operator supports nginx auto-instrumentation")
 	pflag.BoolVar(&enableNodeJSInstrumentation, constants.FlagNodeJS, true, "Controls whether the operator supports nodejs auto-instrumentation")
 	pflag.BoolVar(&enableJavaInstrumentation, constants.FlagJava, true, "Controls whether the operator supports java auto-instrumentation")
+	pflag.BoolVar(&enableCRMetrics, constants.FlagCRMetrics, false, "Controls whether the CR metrics is enabled")
+
 	stringFlagOrEnv(&collectorImage, "collector-image", "RELATED_IMAGE_COLLECTOR", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-collector-releases/opentelemetry-collector:%s", v.OpenTelemetryCollector), "The default OpenTelemetry collector image. This image is used when no image is specified in the CustomResource.")
 	stringFlagOrEnv(&targetAllocatorImage, "target-allocator-image", "RELATED_IMAGE_TARGET_ALLOCATOR", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/target-allocator:%s", v.TargetAllocator), "The default OpenTelemetry target allocator image. This image is used when no image is specified in the CustomResource.")
 	stringFlagOrEnv(&operatorOpAMPBridgeImage, "operator-opamp-bridge-image", "RELATED_IMAGE_OPERATOR_OPAMP_BRIDGE", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/operator-opamp-bridge:%s", v.OperatorOpAMPBridge), "The default OpenTelemetry Operator OpAMP Bridge image. This image is used when no image is specified in the CustomResource.")
@@ -313,6 +316,13 @@ func main() {
 			}
 		}
 	}
+
+	if enableCRMetrics {
+		if metricsErr := otelv1beta1.BootstrapMetrics(); metricsErr != nil {
+			setupLog.Error(metricsErr, "Error bootstrapping CRD metrics")
+		}
+	}
+
 	if cfg.LabelsFilter() != nil {
 		for _, basePattern := range cfg.LabelsFilter() {
 			_, compileErr := regexp.Compile(basePattern)

pkg/constants/env.go

@@ -37,6 +37,8 @@ const (
 	EnvNodeName = "OTEL_RESOURCE_ATTRIBUTES_NODE_NAME"
 	EnvNodeIP   = "OTEL_NODE_IP"
 
+	FlagCRMetrics = "enable-cr-metrics"
+
 	FlagApacheHttpd = "enable-apache-httpd-instrumentation"
 	FlagDotNet      = "enable-dotnet-instrumentation"
 	FlagGo          = "enable-go-instrumentation"