[service] add service.disableOpenCensusBridge gate

This feature gate allows end users to re-enable the opencensus bridge if there's a need for it. This preceeds open-telemetry#10406 and will be taken out of draft once open-telemetry/opentelemetry-collector-contrib#29867 is completed.

Signed-off-by: Alex Boten <[email protected]>

Author: codeboten

.chloggen/codeboten_census-feature-gate.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "add `service.disableOpenCensusBridge` feature gate which is enabled by default to remove the dependency on OpenCensus"
+
+# One or more tracking issues or pull requests related to the change
+issues: [10414]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

internal/featuregates/featuregates.go

@@ -9,3 +9,8 @@ var UseUnifiedEnvVarExpansionRules = featuregate.GlobalRegistry().MustRegister("
 	featuregate.StageBeta,
 	featuregate.WithRegisterFromVersion("v0.103.0"),
 	featuregate.WithRegisterDescription("`${FOO}` will now be expanded as if it was `${env:FOO}` and no longer expands $ENV syntax. See https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/rfcs/env-vars.md for more details. When this feature gate is stable, expandconverter will be removed."))
+
+var DisableOpenCensusBridge = featuregate.GlobalRegistry().MustRegister("service.disableOpenCensusBridge",
+	featuregate.StageBeta,
+	featuregate.WithRegisterFromVersion("v0.104.0"),
+	featuregate.WithRegisterDescription("`Disables the OpenCensus bridge meaning any component still using the OpenCensus SDK will no longer be able to produce telemetry."))

service/internal/proctelemetry/config.go

@@ -28,6 +28,7 @@ import (
 	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/resource"
 
+	"go.opentelemetry.io/collector/internal/featuregates"
 	"go.opentelemetry.io/collector/processor/processorhelper"
 	semconv "go.opentelemetry.io/collector/semconv/v1.18.0"
 )
@@ -67,8 +68,10 @@ func InitMetricReader(ctx context.Context, reader config.MetricReader, asyncErro
 		return initPullExporter(reader.Pull.Exporter, asyncErrorChannel)
 	}
 	if reader.Periodic != nil {
-		opts := []sdkmetric.PeriodicReaderOption{
-			sdkmetric.WithProducer(opencensus.NewMetricProducer()),
+		var opts []sdkmetric.PeriodicReaderOption
+
+		if !featuregates.DisableOpenCensusBridge.IsEnabled() {
+			opts = append(opts, sdkmetric.WithProducer(opencensus.NewMetricProducer()))
 		}
 		if reader.Periodic.Interval != nil {
 			opts = append(opts, sdkmetric.WithInterval(time.Duration(*reader.Periodic.Interval)*time.Millisecond))
@@ -160,18 +163,22 @@ func initPrometheusExporter(prometheusConfig *config.Prometheus, asyncErrorChann
 	if prometheusConfig.Port == nil {
 		return nil, nil, fmt.Errorf("port must be specified")
 	}
-	exporter, err := otelprom.New(
+
+	opts := []otelprom.Option{
 		otelprom.WithRegisterer(promRegistry),
 		// https://github.com/open-telemetry/opentelemetry-collector/issues/8043
 		otelprom.WithoutUnits(),
 		// Disabled for the moment until this becomes stable, and we are ready to break backwards compatibility.
 		otelprom.WithoutScopeInfo(),
-		otelprom.WithProducer(opencensus.NewMetricProducer()),
 		// This allows us to produce metrics that are backwards compatible w/ opencensus
 		otelprom.WithoutCounterSuffixes(),
 		otelprom.WithNamespace("otelcol"),
 		otelprom.WithResourceAsConstantLabels(attribute.NewDenyKeysFilter()),
-	)
+	}
+	if !featuregates.DisableOpenCensusBridge.IsEnabled() {
+		opts = append(opts, otelprom.WithProducer(opencensus.NewMetricProducer()))
+	}
+	exporter, err := otelprom.New(opts...)
 	if err != nil {
 		return nil, nil, fmt.Errorf("error creating otel prometheus exporter: %w", err)
 	}

service/telemetry_test.go

@@ -19,6 +19,8 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config/configtelemetry"
+	"go.opentelemetry.io/collector/featuregate"
+	"go.opentelemetry.io/collector/internal/featuregates"
 	"go.opentelemetry.io/collector/internal/testutil"
 	semconv "go.opentelemetry.io/collector/semconv/v1.18.0"
 	"go.opentelemetry.io/collector/service/internal/proctelemetry"
@@ -42,11 +44,12 @@ func TestTelemetryInit(t *testing.T) {
 	}
 
 	for _, tc := range []struct {
-		name            string
-		disableHighCard bool
-		expectedMetrics map[string]metricValue
-		extendedConfig  bool
-		cfg             *telemetry.Config
+		name                string
+		disableHighCard     bool
+		disableCensusBridge bool
+		expectedMetrics     map[string]metricValue
+		extendedConfig      bool
+		cfg                 *telemetry.Config
 	}{
 		{
 			name: "UseOpenTelemetryForInternalMetrics",
@@ -214,8 +217,55 @@ func TestTelemetryInit(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "DisableOpenCensusBridge",
+			expectedMetrics: map[string]metricValue{
+				metricPrefix + otelPrefix + counterName: {
+					value: 13,
+					labels: map[string]string{
+						"service_name":        "otelcol",
+						"service_version":     "latest",
+						"service_instance_id": testInstanceID,
+					},
+				},
+				metricPrefix + grpcPrefix + counterName: {
+					value: 11,
+					labels: map[string]string{
+						"net_sock_peer_addr":  "",
+						"net_sock_peer_name":  "",
+						"net_sock_peer_port":  "",
+						"service_name":        "otelcol",
+						"service_version":     "latest",
+						"service_instance_id": testInstanceID,
+					},
+				},
+				metricPrefix + httpPrefix + counterName: {
+					value: 10,
+					labels: map[string]string{
+						"net_host_name":       "",
+						"net_host_port":       "",
+						"service_name":        "otelcol",
+						"service_version":     "latest",
+						"service_instance_id": testInstanceID,
+					},
+				},
+				"target_info": {
+					value: 0,
+					labels: map[string]string{
+						"service_name":        "otelcol",
+						"service_version":     "latest",
+						"service_instance_id": testInstanceID,
+					},
+				},
+			},
+			disableCensusBridge: true,
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
+			require.NoError(t, featuregate.GlobalRegistry().Set(featuregates.DisableOpenCensusBridge.ID(), tc.disableCensusBridge))
+			t.Cleanup(func() {
+				require.NoError(t, featuregate.GlobalRegistry().Set(featuregates.DisableOpenCensusBridge.ID(), true))
+			})
 			if tc.extendedConfig {
 				tc.cfg.Metrics.Readers = []config.MetricReader{
 					{