add stdout exporter support

Internal metrics can now be additionally configure to export using the stdout exporter.

Linked issue: open-telemetry#7641

Signed-off-by: Alex Boten <aboten@lightstep.com>

.chloggen/codeboten_add-console-exporter.yaml

@@ -0,0 +1,18 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# 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 support for exporting internal metrics to the console
+
+# One or more tracking issues or pull requests related to the change
+issues: [7641]
+
+# (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: |
+  Internal collector metrics can now be exported to the console
+  using the otel-go stdout exporter.

cmd/otelcorecol/go.mod

@@ -94,6 +94,7 @@ require (
 	go.opentelemetry.io/otel v1.16.0 // indirect
 	go.opentelemetry.io/otel/bridge/opencensus v0.39.0 // indirect
 	go.opentelemetry.io/otel/exporters/prometheus v0.39.0 // indirect
+	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0 // indirect
 	go.opentelemetry.io/otel/metric v1.16.0 // indirect
 	go.opentelemetry.io/otel/sdk v1.16.0 // indirect
 	go.opentelemetry.io/otel/sdk/metric v0.39.0 // indirect

cmd/otelcorecol/go.sum

@@ -1026,6 +1026,8 @@ go.opentelemetry.io/otel/bridge/opencensus v0.39.0 h1:YHivttTaDhbZIHuPlg1sWsy2P5
 go.opentelemetry.io/otel/bridge/opencensus v0.39.0/go.mod h1:vZ4537pNjFDXEx//WldAR6Ro2LC8wwmFC76njAXwNPE=
 go.opentelemetry.io/otel/exporters/prometheus v0.39.0 h1:whAaiHxOatgtKd+w0dOi//1KUxj3KoPINZdtDaDj3IA=
 go.opentelemetry.io/otel/exporters/prometheus v0.39.0/go.mod h1:4jo5Q4CROlCpSPsXLhymi+LYrDXd2ObU5wbKayfZs7Y=
+go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0 h1:fl2WmyenEf6LYYlfHAtCUEDyGcpwJNqD4dHGO7PVm4w=
+go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0/go.mod h1:csyQxQ0UHHKVA8KApS7eUO/klMO5sd/av5CNZNU4O6w=
 go.opentelemetry.io/otel/metric v1.16.0 h1:RbrpwVG1Hfv85LgnZ7+txXioPDoh6EdbZHo26Q3hqOo=
 go.opentelemetry.io/otel/metric v1.16.0/go.mod h1:QE47cpOmkwipPiefDwo2wDzwJrlfxxNYodqc4xnGCo4=
 go.opentelemetry.io/otel/sdk v1.16.0 h1:Z1Ok1YsijYL0CSJpHt4cS3wDDh7p572grzNrBMiMWgE=

go.mod

@@ -30,6 +30,7 @@ require (
 	go.opentelemetry.io/otel v1.16.0
 	go.opentelemetry.io/otel/bridge/opencensus v0.39.0
 	go.opentelemetry.io/otel/exporters/prometheus v0.39.0
+	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0
 	go.opentelemetry.io/otel/metric v1.16.0
 	go.opentelemetry.io/otel/sdk v1.16.0
 	go.opentelemetry.io/otel/sdk/metric v0.39.0

go.sum

@@ -411,6 +411,8 @@ go.opentelemetry.io/otel/bridge/opencensus v0.39.0 h1:YHivttTaDhbZIHuPlg1sWsy2P5
 go.opentelemetry.io/otel/bridge/opencensus v0.39.0/go.mod h1:vZ4537pNjFDXEx//WldAR6Ro2LC8wwmFC76njAXwNPE=
 go.opentelemetry.io/otel/exporters/prometheus v0.39.0 h1:whAaiHxOatgtKd+w0dOi//1KUxj3KoPINZdtDaDj3IA=
 go.opentelemetry.io/otel/exporters/prometheus v0.39.0/go.mod h1:4jo5Q4CROlCpSPsXLhymi+LYrDXd2ObU5wbKayfZs7Y=
+go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0 h1:fl2WmyenEf6LYYlfHAtCUEDyGcpwJNqD4dHGO7PVm4w=
+go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v0.39.0/go.mod h1:csyQxQ0UHHKVA8KApS7eUO/klMO5sd/av5CNZNU4O6w=
 go.opentelemetry.io/otel/metric v1.16.0 h1:RbrpwVG1Hfv85LgnZ7+txXioPDoh6EdbZHo26Q3hqOo=
 go.opentelemetry.io/otel/metric v1.16.0/go.mod h1:QE47cpOmkwipPiefDwo2wDzwJrlfxxNYodqc4xnGCo4=
 go.opentelemetry.io/otel/sdk v1.16.0 h1:Z1Ok1YsijYL0CSJpHt4cS3wDDh7p572grzNrBMiMWgE=

service/internal/proctelemetry/config.go

@@ -5,15 +5,18 @@ package proctelemetry // import "go.opentelemetry.io/collector/service/internal/
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"net/http"
+	"os"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/bridge/opencensus"
 	otelprom "go.opentelemetry.io/otel/exporters/prometheus"
+	"go.opentelemetry.io/otel/exporters/stdout/stdoutmetric"
 	"go.opentelemetry.io/otel/sdk/instrumentation"
 	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/metric/aggregation"
@@ -52,6 +55,9 @@ func InitMetricReader(ctx context.Context, reader telemetry.MetricReader, asyncE
 	if reader.Pull != nil {
 		return initExporter(ctx, reader.Pull.Exporter, asyncErrorChannel)
 	}
+	if reader.Periodic != nil {
+		return initExporter(ctx, reader.Periodic.Exporter, asyncErrorChannel)
+	}
 	return nil, nil, fmt.Errorf("unsupported metric reader type %v", reader)
 }
 
@@ -148,9 +154,21 @@ func initPrometheusExporter(prometheusConfig *telemetry.Prometheus, asyncErrorCh
 	return exporter, InitPrometheusServer(promRegistry, fmt.Sprintf("%s:%d", *prometheusConfig.Host, *prometheusConfig.Port), asyncErrorChannel), nil
 }
 
-func initExporter(_ context.Context, exporter telemetry.MetricExporter, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {
+func initExporter(ctx context.Context, exporter telemetry.MetricExporter, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {
 	if exporter.Prometheus != nil {
 		return initPrometheusExporter(exporter.Prometheus, asyncErrorChannel)
 	}
+	if exporter.Console != nil {
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+
+		exp, err := stdoutmetric.New(
+			stdoutmetric.WithEncoder(enc),
+		)
+		if err != nil {
+			return nil, nil, err
+		}
+		return sdkmetric.NewPeriodicReader(exp), nil, nil
+	}
 	return nil, nil, fmt.Errorf("no valid exporter")
 }

service/telemetry/config.go

@@ -134,7 +134,6 @@ func (c *Config) Validate() error {
 
 func (mr *MetricReader) Unmarshal(conf *confmap.Conf) error {
 	if !obsreportconfig.UseOtelWithSDKConfigurationForInternalTelemetryFeatureGate.IsEnabled() {
-		fmt.Println(obsreportconfig.UseOtelWithSDKConfigurationForInternalTelemetryFeatureGate.IsEnabled())
 		// only unmarshal if feature gate is enabled
 		return nil
 	}
@@ -151,7 +150,11 @@ func (mr *MetricReader) Unmarshal(conf *confmap.Conf) error {
 		if mr.Pull.Exporter.Prometheus == nil {
 			return fmt.Errorf("invalid exporter configuration")
 		}
-		return nil
+	}
+	if mr.Periodic != nil {
+		if mr.Periodic.Exporter.Console == nil {
+			return fmt.Errorf("invalid exporter configuration")
+		}
 	}
 
 	return fmt.Errorf("unsupported metric reader type %s", conf.AllKeys())