adding test for extendedConfig w/ metric readers

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

.chloggen/codeboten_may-29-otlp-export.yaml

@@ -0,0 +1,21 @@
+# 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 ability to configure prometheus export via `metric_readers`"
+
+# 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: |
+ This enables end users to configure additional prometheus exporters for the collector's telemetry
+ via the `metric_readers` configuration option. Configuring prometheus through the existing method
+ of setting the service::metrics::address will continue to work, and only log a warning for users
+ who have enabled the `telemetry.useOtelWithSDKConfigurationForInternalTelemetry` feature gate.
+

exporter/otlpexporter/go.mod

@@ -52,6 +52,7 @@ require (
  go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.42.1-0.20230612162650-64be7e574a17 // indirect
  go.opentelemetry.io/otel v1.16.0 // indirect
  go.opentelemetry.io/otel/metric v1.16.0 // indirect
+ go.opentelemetry.io/otel/sdk v1.16.0 // indirect
  go.opentelemetry.io/otel/trace v1.16.0 // indirect
  go.uber.org/atomic v1.10.0 // indirect
  go.uber.org/multierr v1.11.0 // indirect

exporter/otlpexporter/go.sum

@@ -298,6 +298,7 @@ go.opentelemetry.io/otel/exporters/prometheus v0.39.0 h1:whAaiHxOatgtKd+w0dOi//1
 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.opentelemetry.io/otel/sdk v1.16.0/go.mod h1:tMsIuKXuuIWPBAOrH+eHtvhTL+SntFtXF9QD68aP6p4=
 go.opentelemetry.io/otel/sdk/metric v0.39.0 h1:Kun8i1eYf48kHH83RucG93ffz0zGV1sh46FAScOTuDI=
 go.opentelemetry.io/otel/trace v1.16.0 h1:8JRpaObFoW0pxuVPapkgH8UhHQj+bJW8jJsCZEu5MQs=
 go.opentelemetry.io/otel/trace v1.16.0/go.mod h1:Yt9vYq1SdNz3xdjZZK7wcXv1qv2pwLkqr2QVwea0ef0=

exporter/otlphttpexporter/go.mod

@@ -57,6 +57,7 @@ require (
  go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.42.0 // indirect
  go.opentelemetry.io/otel v1.16.0 // indirect
  go.opentelemetry.io/otel/metric v1.16.0 // indirect
+ go.opentelemetry.io/otel/sdk v1.16.0 // indirect
  go.opentelemetry.io/otel/trace v1.16.0 // indirect
  go.uber.org/atomic v1.10.0 // indirect
  go.uber.org/multierr v1.11.0 // indirect

exporter/otlphttpexporter/go.sum

@@ -977,6 +977,7 @@ go.opentelemetry.io/otel/exporters/prometheus v0.39.0 h1:whAaiHxOatgtKd+w0dOi//1
 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.opentelemetry.io/otel/sdk v1.16.0/go.mod h1:tMsIuKXuuIWPBAOrH+eHtvhTL+SntFtXF9QD68aP6p4=
 go.opentelemetry.io/otel/sdk/metric v0.39.0 h1:Kun8i1eYf48kHH83RucG93ffz0zGV1sh46FAScOTuDI=
 go.opentelemetry.io/otel/trace v1.16.0 h1:8JRpaObFoW0pxuVPapkgH8UhHQj+bJW8jJsCZEu5MQs=
 go.opentelemetry.io/otel/trace v1.16.0/go.mod h1:Yt9vYq1SdNz3xdjZZK7wcXv1qv2pwLkqr2QVwea0ef0=

go.mod

@@ -5,6 +5,7 @@ go 1.19
 require (
  contrib.go.opencensus.io/exporter/prometheus v0.4.2
  github.com/google/uuid v1.3.0
+ github.com/mitchellh/mapstructure v1.5.0
  github.com/prometheus/client_golang v1.16.0
  github.com/prometheus/client_model v0.4.0
  github.com/prometheus/common v0.44.0
@@ -60,7 +61,6 @@ require (
  github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
  github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
  github.com/mitchellh/copystructure v1.2.0 // indirect
- github.com/mitchellh/mapstructure v1.5.0 // indirect
  github.com/mitchellh/reflectwalk v1.0.2 // indirect
  github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
  github.com/modern-go/reflect2 v1.0.2 // indirect

internal/testutil/testutil.go

@@ -13,6 +13,7 @@ import (
 
  "github.com/stretchr/testify/assert"
  "github.com/stretchr/testify/require"
+
  "go.opentelemetry.io/collector/service/telemetry"
 )
 

service/internal/proctelemetry/config.go

@@ -4,14 +4,25 @@
 package proctelemetry // import "go.opentelemetry.io/collector/service/internal/proctelemetry"
 
 import (
+ "context"
+ "errors"
+ "fmt"
+ "net/http"
+ "strings"
+
+ "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/sdk/instrumentation"
  sdkmetric "go.opentelemetry.io/otel/sdk/metric"
  "go.opentelemetry.io/otel/sdk/metric/aggregation"
  "go.opentelemetry.io/otel/sdk/resource"
 
  "go.opentelemetry.io/collector/obsreport"
  semconv "go.opentelemetry.io/collector/semconv/v1.18.0"
+ "go.opentelemetry.io/collector/service/telemetry"
 )
 
 const (
@@ -21,6 +32,12 @@ const (
 
  // http Instrumentation Name
  HTTPInstrumentation = "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+
+ // supported metric readers
+ pullMetricReader = "pull"
+
+ // supported exporters
+ prometheueExporter = "prometheus"
 )
 
 var (
@@ -38,6 +55,20 @@ var (
  }
 )
 
+func InitMetricReader(ctx context.Context, name string, reader any, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {
+ readerType := strings.Split(name, "/")[0]
+ switch readerType {
+ case pullMetricReader:
+ r, ok := reader.(telemetry.PullMetricReader)
+ if !ok {
+ return nil, nil, fmt.Errorf("invalid metric reader configuration: %v", reader)
+ }
+ return initExporter(ctx, r.Exporter, asyncErrorChannel)
+ default:
+ return nil, nil, fmt.Errorf("unsupported metric reader type: %s", readerType)
+ }
+}
+
 func InitOpenTelemetry(res *resource.Resource, options []sdkmetric.Option, disableHighCardinality bool) (*sdkmetric.MeterProvider, error) {
  opts := []sdkmetric.Option{
  sdkmetric.WithResource(res),
@@ -50,6 +81,21 @@ func InitOpenTelemetry(res *resource.Resource, options []sdkmetric.Option, disab
  ), nil
 }
 
+func InitPrometheusServer(registry *prometheus.Registry, address string, asyncErrorChannel chan error) *http.Server {
+ mux := http.NewServeMux()
+ mux.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
+ server := &http.Server{
+ Addr: address,
+ Handler: mux,
+ }
+ go func() {
+ if serveErr := server.ListenAndServe(); serveErr != nil && !errors.Is(serveErr, http.ErrServerClosed) {
+ asyncErrorChannel <- serveErr
+ }
+ }()
+ return server
+}
+
 func batchViews(disableHighCardinality bool) []sdkmetric.View {
  views := []sdkmetric.View{
  sdkmetric.NewView(
@@ -92,3 +138,44 @@ func cardinalityFilter(kvs ...attribute.KeyValue) attribute.Filter {
  return !filter.HasValue(kv.Key)
  }
 }
+
+func initPrometheusExporter(prometheusConfig telemetry.Prometheus, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {
+ promRegistry := prometheus.NewRegistry()
+ if prometheusConfig.Host == nil {
+ return nil, nil, fmt.Errorf("host must be specified")
+ }
+ if prometheusConfig.Port == nil {
+ return nil, nil, fmt.Errorf("port must be specified")
+ }
+ wrappedRegisterer := prometheus.WrapRegistererWithPrefix("otelcol_", promRegistry)
+ // We can remove `otelprom.WithoutUnits()` when the otel-go start exposing prometheus metrics using the OpenMetrics format
+ // which includes metric units that prometheusreceiver uses to trim unit's suffixes from metric names.
+ // https://github.com/open-telemetry/opentelemetry-go/issues/3468
+ exporter, err := otelprom.New(
+ otelprom.WithRegisterer(wrappedRegisterer),
+ otelprom.WithoutUnits(),
+ // Disabled for the moment until this becomes stable, and we are ready to break backwards compatibility.
+ otelprom.WithoutScopeInfo())
+ if err != nil {
+ return nil, nil, fmt.Errorf("error creating otel prometheus exporter: %w", err)
+ }
+
+ exporter.RegisterProducer(opencensus.NewMetricProducer())
+ return exporter, InitPrometheusServer(promRegistry, fmt.Sprintf("%s:%d", *prometheusConfig.Host, *prometheusConfig.Port), asyncErrorChannel), nil
+}
+
+func initExporter(_ context.Context, exporters telemetry.MetricExporter, asyncErrorChannel chan error) (sdkmetric.Reader, *http.Server, error) {
+ for exporterType, exporter := range exporters {
+ switch exporterType {
+ case prometheueExporter:
+ e, ok := exporter.(telemetry.Prometheus)
+ if !ok {
+ return nil, nil, fmt.Errorf("prometheus exporter invalid: %v", exporter)
+ }
+ return initPrometheusExporter(e, asyncErrorChannel)
+ default:
+ return nil, nil, fmt.Errorf("unsupported metric exporter type: %s", exporterType)
+ }
+ }
+ return nil, nil, fmt.Errorf("no valid exporter: %v", exporters)
+}

service/internal/proctelemetry/config_test.go

@@ -2,3 +2,72 @@
 // SPDX-License-Identifier: Apache-2.0
 
 package proctelemetry
+
+import (
+ "context"
+ "errors"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+
+ "go.opentelemetry.io/collector/service/telemetry"
+)
+
+func strPtr(s string) *string {
+ return &s
+}
+
+func intPtr(i int) *int {
+ return &i
+}
+
+func TestMetricReader(t *testing.T) {
+ testCases := []struct {
+ name string
+ reader any
+ args any
+ err error
+ }{
+ {
+ name: "noreader",
+ err: errors.New("unsupported metric reader type: noreader"),
+ },
+ {
+ name: "pull/prometheus-invalid-config-no-host",
+ reader: telemetry.PullMetricReader{
+ Exporter: telemetry.MetricExporter{
+ "prometheus": telemetry.Prometheus{},
+ },
+ },
+ err: errors.New("host must be specified"),
+ },
+ {
+ name: "pull/prometheus-invalid-config-no-port",
+ reader: telemetry.PullMetricReader{
+ Exporter: telemetry.MetricExporter{
+ "prometheus": telemetry.Prometheus{
+ Host: strPtr("locahost"),
+ },
+ },
+ },
+ err: errors.New("port must be specified"),
+ },
+ {
+ name: "pull/prometheus-invalid-config-no-port",
+ reader: telemetry.PullMetricReader{
+ Exporter: telemetry.MetricExporter{
+ "prometheus": telemetry.Prometheus{
+ Host: strPtr("locahost"),
+ Port: intPtr(8080),
+ },
+ },
+ },
+ },
+ }
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ _, _, err := InitMetricReader(context.Background(), tc.name, tc.reader, make(chan error))
+ assert.Equal(t, tc.err, err)
+ })
+ }
+}