Reduce the frequency of HCP OTEL metric exports to minutely

.changelog/18584.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+Reduce the frequency of metric exports from Consul to HCP from every 10s to every 1m
+```

agent/hcp/deps.go

@@ -82,7 +82,7 @@ func sink(
 		return nil, fmt.Errorf("failed to init config provider: %w", err)
 	}
 
-	reader := telemetry.NewOTELReader(metricsClient, cfgProvider, telemetry.DefaultExportInterval)
+	reader := telemetry.NewOTELReader(metricsClient, cfgProvider)
 	sinkOpts := &telemetry.OTELSinkOpts{
 		Reader:         reader,
 		ConfigProvider: cfgProvider,

agent/hcp/telemetry/otel_exporter.go

@@ -27,32 +27,32 @@ type EndpointProvider interface {
 	GetEndpoint() *url.URL
 }
 
-// OTELExporter is a custom implementation of a OTEL Metrics SDK metrics.Exporter.
+// otelExporter is a custom implementation of a OTEL Metrics SDK metrics.Exporter.
 // The exporter is used by a OTEL Metrics SDK PeriodicReader to export aggregated metrics.
 // This allows us to use a custom client - HCP authenticated MetricsClient.
-type OTELExporter struct {
+type otelExporter struct {
 	client           MetricsClient
 	endpointProvider EndpointProvider
 }
 
-// NewOTELExporter returns a configured OTELExporter.
-func NewOTELExporter(client MetricsClient, endpointProvider EndpointProvider) *OTELExporter {
-	return &OTELExporter{
+// newOTELExporter returns a configured OTELExporter.
+func newOTELExporter(client MetricsClient, endpointProvider EndpointProvider) *otelExporter {
+	return &otelExporter{
 		client:           client,
 		endpointProvider: endpointProvider,
 	}
 }
 
 // Temporality returns the Cumulative temporality for metrics aggregation.
 // Telemetry Gateway stores metrics in Prometheus format, so use Cummulative aggregation as default.
-func (e *OTELExporter) Temporality(_ metric.InstrumentKind) metricdata.Temporality {
+func (e *otelExporter) Temporality(_ metric.InstrumentKind) metricdata.Temporality {
 	return metricdata.CumulativeTemporality
 }
 
 // Aggregation returns the Aggregation to use for an instrument kind.
 // The default implementation provided by the OTEL Metrics SDK library DefaultAggregationSelector panics.
 // This custom version replicates that logic, but removes the panic.
-func (e *OTELExporter) Aggregation(kind metric.InstrumentKind) aggregation.Aggregation {
+func (e *otelExporter) Aggregation(kind metric.InstrumentKind) aggregation.Aggregation {
 	switch kind {
 	case metric.InstrumentKindObservableGauge:
 		return aggregation.LastValue{}
@@ -67,7 +67,7 @@ func (e *OTELExporter) Aggregation(kind metric.InstrumentKind) aggregation.Aggre
 }
 
 // Export serializes and transmits metric data to a receiver.
-func (e *OTELExporter) Export(ctx context.Context, metrics *metricdata.ResourceMetrics) error {
+func (e *otelExporter) Export(ctx context.Context, metrics *metricdata.ResourceMetrics) error {
 	endpoint := e.endpointProvider.GetEndpoint()
 	if endpoint == nil {
 		return nil
@@ -89,13 +89,13 @@ func (e *OTELExporter) Export(ctx context.Context, metrics *metricdata.ResourceM
 }
 
 // ForceFlush is a no-op, as the MetricsClient client holds no state.
-func (e *OTELExporter) ForceFlush(ctx context.Context) error {
+func (e *otelExporter) ForceFlush(ctx context.Context) error {
 	goMetrics.IncrCounter(internalMetricExporterForceFlush, 1)
 	return ctx.Err()
 }
 
 // Shutdown is a no-op, as the MetricsClient is a HTTP client that requires no graceful shutdown.
-func (e *OTELExporter) Shutdown(ctx context.Context) error {
+func (e *otelExporter) Shutdown(ctx context.Context) error {
 	goMetrics.IncrCounter(internalMetricExporterShutdown, 1)
 	return ctx.Err()
 }

agent/hcp/telemetry/otel_exporter_test.go

@@ -40,7 +40,7 @@ func (m *mockEndpointProvider) GetEndpoint() *url.URL { return m.endpoint }
 
 func TestTemporality(t *testing.T) {
 	t.Parallel()
-	exp := &OTELExporter{}
+	exp := &otelExporter{}
 	require.Equal(t, metricdata.CumulativeTemporality, exp.Temporality(metric.InstrumentKindCounter))
 }
 
@@ -66,7 +66,7 @@ func TestAggregation(t *testing.T) {
 		test := test
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
-			exp := &OTELExporter{}
+			exp := &otelExporter{}
 			require.Equal(t, test.expAgg, exp.Aggregation(test.kind))
 		})
 	}
@@ -125,7 +125,7 @@ func TestExport(t *testing.T) {
 				}
 			}
 
-			exp := NewOTELExporter(test.client, provider)
+			exp := newOTELExporter(test.client, provider)
 
 			err := exp.Export(context.Background(), test.metrics)
 			if test.wantErr != "" {
@@ -182,7 +182,7 @@ func TestExport_CustomMetrics(t *testing.T) {
 			u, err := url.Parse(testExportEndpoint)
 			require.NoError(t, err)
 
-			exp := NewOTELExporter(tc.client, &mockEndpointProvider{
+			exp := newOTELExporter(tc.client, &mockEndpointProvider{
 				endpoint: u,
 			})
 
@@ -212,7 +212,7 @@ func TestExport_CustomMetrics(t *testing.T) {
 
 func TestForceFlush(t *testing.T) {
 	t.Parallel()
-	exp := &OTELExporter{}
+	exp := &otelExporter{}
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 
@@ -222,7 +222,7 @@ func TestForceFlush(t *testing.T) {
 
 func TestShutdown(t *testing.T) {
 	t.Parallel()
-	exp := &OTELExporter{}
+	exp := &otelExporter{}
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 

agent/hcp/telemetry/otel_sink.go

@@ -20,13 +20,26 @@ import (
 	"go.opentelemetry.io/otel/sdk/resource"
 )
 
-// DefaultExportInterval is a default time interval between export of aggregated metrics.
-const DefaultExportInterval = 10 * time.Second
+const (
+	// defaultExportInterval is a default time interval between export of aggregated metrics.
+	// At the time of writing this is the same as the otelsdk.Reader's export interval.
+	defaultExportInterval = 60 * time.Second
+
+	// defaultExportTimeout is the time the otelsdk.Reader waits on an export before cancelling it.
+	// At the time of writing this is the same as the otelsdk.Reader's export timeout default.
+	//
+	// note: in practice we are more likely to hit the http.Client Timeout in telemetry.MetricsClient.
+	// That http.Client Timeout is 15 seconds (at the time of writing). The otelsdk.Reader will use
+	// defaultExportTimeout for the entire Export call, but since the http.Client's Timeout is 15s,
+	// we should hit that first before reaching the 30 second timeout set here.
+	defaultExportTimeout = 30 * time.Second
+)
 
 // ConfigProvider is required to provide custom metrics processing.
 type ConfigProvider interface {
 	// GetLabels should return a set of OTEL attributes added by default all metrics.
 	GetLabels() map[string]string
+
 	// GetFilters should return filtesr that are required to enable metric processing.
 	// Filters act as an allowlist to collect only the required metrics.
 	GetFilters() *regexp.Regexp
@@ -75,9 +88,12 @@ type OTELSink struct {
 // NewOTELReader returns a configured OTEL PeriodicReader to export metrics every X seconds.
 // It configures the reader with a custom OTELExporter with a MetricsClient to transform and export
 // metrics in OTLP format to an external url.
-func NewOTELReader(client MetricsClient, endpointProvider EndpointProvider, exportInterval time.Duration) otelsdk.Reader {
-	exporter := NewOTELExporter(client, endpointProvider)
-	return otelsdk.NewPeriodicReader(exporter, otelsdk.WithInterval(exportInterval))
+func NewOTELReader(client MetricsClient, endpointProvider EndpointProvider) otelsdk.Reader {
+	return otelsdk.NewPeriodicReader(
+		newOTELExporter(client, endpointProvider),
+		otelsdk.WithInterval(defaultExportInterval),
+		otelsdk.WithTimeout(defaultExportTimeout),
+	)
 }
 
 // NewOTELSink returns a sink which fits the Go Metrics MetricsSink interface.