mirror of https://github.com/hashicorp/consul
108 lines
3.7 KiB
Go
108 lines
3.7 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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package telemetry
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import (
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"context"
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"fmt"
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"net/url"
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goMetrics "github.com/armon/go-metrics"
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"go.opentelemetry.io/otel/sdk/metric"
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"go.opentelemetry.io/otel/sdk/metric/aggregation"
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"go.opentelemetry.io/otel/sdk/metric/metricdata"
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metricpb "go.opentelemetry.io/proto/otlp/metrics/v1"
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)
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// MetricsClient exports Consul metrics in OTLP format to the desired endpoint.
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type MetricsClient interface {
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ExportMetrics(ctx context.Context, protoMetrics *metricpb.ResourceMetrics, endpoint string) error
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}
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// EndpointProvider provides the endpoint where metrics are exported to by the OTELExporter.
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// EndpointProvider exposes the GetEndpoint() interface method to fetch the endpoint.
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// This abstraction layer offers flexibility, in particular for dynamic configuration or changes to the endpoint.
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// The OTELExporter calls the Disabled interface to verify that it should actually export metrics.
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type EndpointProvider interface {
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Disabled
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GetEndpoint() *url.URL
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}
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// otelExporter is a custom implementation of a OTEL Metrics SDK metrics.Exporter.
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// The exporter is used by a OTEL Metrics SDK PeriodicReader to export aggregated metrics.
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// This allows us to use a custom client - HCP authenticated MetricsClient.
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type otelExporter struct {
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client MetricsClient
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endpointProvider EndpointProvider
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}
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// newOTELExporter returns a configured OTELExporter.
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func newOTELExporter(client MetricsClient, endpointProvider EndpointProvider) *otelExporter {
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return &otelExporter{
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client: client,
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endpointProvider: endpointProvider,
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}
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}
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// Temporality returns the Cumulative temporality for metrics aggregation.
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// Telemetry Gateway stores metrics in Prometheus format, so use Cummulative aggregation as default.
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func (e *otelExporter) Temporality(_ metric.InstrumentKind) metricdata.Temporality {
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return metricdata.CumulativeTemporality
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}
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// Aggregation returns the Aggregation to use for an instrument kind.
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// The default implementation provided by the OTEL Metrics SDK library DefaultAggregationSelector panics.
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// This custom version replicates that logic, but removes the panic.
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func (e *otelExporter) Aggregation(kind metric.InstrumentKind) aggregation.Aggregation {
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switch kind {
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case metric.InstrumentKindObservableGauge:
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return aggregation.LastValue{}
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case metric.InstrumentKindHistogram:
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return aggregation.ExplicitBucketHistogram{
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Boundaries: []float64{0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000},
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NoMinMax: false,
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}
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}
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// for metric.InstrumentKindCounter and others, default to sum.
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return aggregation.Sum{}
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}
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// Export serializes and transmits metric data to a receiver.
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func (e *otelExporter) Export(ctx context.Context, metrics *metricdata.ResourceMetrics) error {
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if e.endpointProvider.IsDisabled() {
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return nil
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}
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endpoint := e.endpointProvider.GetEndpoint()
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if endpoint == nil {
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return nil
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}
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otlpMetrics := transformOTLP(metrics)
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if isEmpty(otlpMetrics) {
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return nil
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}
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err := e.client.ExportMetrics(ctx, otlpMetrics, endpoint.String())
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if err != nil {
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goMetrics.IncrCounter(internalMetricExportFailure, 1)
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return fmt.Errorf("failed to export metrics: %w", err)
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}
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goMetrics.IncrCounter(internalMetricExportSuccess, 1)
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return nil
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}
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// ForceFlush is a no-op, as the MetricsClient client holds no state.
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func (e *otelExporter) ForceFlush(ctx context.Context) error {
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goMetrics.IncrCounter(internalMetricExporterForceFlush, 1)
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return ctx.Err()
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}
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// Shutdown is a no-op, as the MetricsClient is a HTTP client that requires no graceful shutdown.
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func (e *otelExporter) Shutdown(ctx context.Context) error {
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goMetrics.IncrCounter(internalMetricExporterShutdown, 1)
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return ctx.Err()
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}
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