[pkg/otlp/model] Move code from contrib repository (#9239)

* [exporter/datadogexporter] Copy main branch contents

* Decouple translator configuration from Collector configuration (open-telemetry/opentelemetry-collector-contrib#5270)

* Use a `Consumer` interface for decoupling from zorkian's package (open-telemetry/opentelemetry-collector-contrib#5315)

* Make tests pass

LICENSE-3rdparty.csv

@@ -63,8 +63,8 @@ core,github.com/DataDog/sketches-go/ddsketch,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/sketches-go/ddsketch/encoding,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/sketches-go/ddsketch/mapping,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/sketches-go/ddsketch/pb/sketchpb,Apache-2.0,"Datadog, Inc."
-core,github.com/DataDog/sketches-go/ddsketch/store,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/sketches-go/ddsketch/stat,Apache-2.0,"Datadog, Inc."
+core,github.com/DataDog/sketches-go/ddsketch/store,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/viper,MIT,"Datadog, Inc."
 core,github.com/DataDog/watermarkpodautoscaler/api/v1alpha1,Apache-2.0,"Datadog, Inc."
 core,github.com/DataDog/zstd,BSD-3-Clause,"Datadog, Inc."

pkg/otlp/model/translator/config.go

@@ -0,0 +1,142 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package translator
+
+import "fmt"
+
+type translatorConfig struct {
+	// metrics export behavior
+	HistMode                 HistogramMode
+	SendCountSum             bool
+	Quantiles                bool
+	SendMonotonic            bool
+	ResourceAttributesAsTags bool
+
+	// cache configuration
+	sweepInterval int64
+	deltaTTL      int64
+
+	// hostname provider configuration
+	fallbackHostnameProvider HostnameProvider
+}
+
+// Option is a translator creation option.
+type Option func(*translatorConfig) error
+
+// WithDeltaTTL sets the delta TTL for cumulative metrics datapoints.
+// By default, 3600 seconds are used.
+func WithDeltaTTL(deltaTTL int64) Option {
+	return func(t *translatorConfig) error {
+		if deltaTTL <= 0 {
+			return fmt.Errorf("time to live must be positive: %d", deltaTTL)
+		}
+		t.deltaTTL = deltaTTL
+		t.sweepInterval = 1
+		if t.deltaTTL > 1 {
+			t.sweepInterval = t.deltaTTL / 2
+		}
+		return nil
+	}
+}
+
+// WithFallbackHostnameProvider sets the fallback hostname provider.
+// By default, an empty hostname is used as a fallback.
+func WithFallbackHostnameProvider(provider HostnameProvider) Option {
+	return func(t *translatorConfig) error {
+		t.fallbackHostnameProvider = provider
+		return nil
+	}
+}
+
+// WithQuantiles enables quantiles exporting for summary metrics.
+func WithQuantiles() Option {
+	return func(t *translatorConfig) error {
+		t.Quantiles = true
+		return nil
+	}
+}
+
+// WithResourceAttributesAsTags sets resource attributes as tags.
+func WithResourceAttributesAsTags() Option {
+	return func(t *translatorConfig) error {
+		t.ResourceAttributesAsTags = true
+		return nil
+	}
+}
+
+// HistogramMode is an export mode for OTLP Histogram metrics.
+type HistogramMode string
+
+const (
+	// HistogramModeNoBuckets disables bucket export.
+	HistogramModeNoBuckets HistogramMode = "nobuckets"
+	// HistogramModeCounters exports buckets as Datadog counts.
+	HistogramModeCounters HistogramMode = "counters"
+	// HistogramModeDistributions exports buckets as Datadog distributions.
+	HistogramModeDistributions HistogramMode = "distributions"
+)
+
+// WithHistogramMode sets the histograms mode.
+// The default mode is HistogramModeOff.
+func WithHistogramMode(mode HistogramMode) Option {
+	return func(t *translatorConfig) error {
+
+		switch mode {
+		case HistogramModeNoBuckets, HistogramModeCounters:
+			t.HistMode = mode
+		default:
+			return fmt.Errorf("unknown histogram mode: %q", mode)
+		}
+		return nil
+	}
+}
+
+// WithCountSumMetrics exports .count and .sum histogram metrics.
+func WithCountSumMetrics() Option {
+	return func(t *translatorConfig) error {
+		t.SendCountSum = true
+		return nil
+	}
+}
+
+// NumberMode is an export mode for OTLP Number metrics.
+type NumberMode string
+
+const (
+	// NumberModeCumulativeToDelta calculates delta for
+	// cumulative monotonic metrics in the client side and reports
+	// them as Datadog counts.
+	NumberModeCumulativeToDelta NumberMode = "cumulative_to_delta"
+
+	// NumberModeRawValue reports the raw value for cumulative monotonic
+	// metrics as a Datadog gauge.
+	NumberModeRawValue NumberMode = "raw_value"
+)
+
+// WithNumberMode sets the number mode.
+// The default mode is NumberModeCumulativeToDelta.
+func WithNumberMode(mode NumberMode) Option {
+	return func(t *translatorConfig) error {
+		switch mode {
+		case NumberModeCumulativeToDelta:
+			t.SendMonotonic = true
+		case NumberModeRawValue:
+			t.SendMonotonic = false
+		default:
+			return fmt.Errorf("unknown number mode: %q", mode)
+		}
+		return nil
+	}
+}

pkg/otlp/model/translator/consumer.go

@@ -0,0 +1,71 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package translator
+
+import (
+	"context"
+
+	"github.com/DataDog/datadog-agent/pkg/quantile"
+)
+
+// MetricDataType is a timeseries-style metric type.
+type MetricDataType int
+
+const (
+	// Gauge is the Datadog Gauge metric type.
+	Gauge MetricDataType = iota
+	// Count is the Datadog Count metric type.
+	Count
+)
+
+// TimeSeriesConsumer is timeseries consumer.
+type TimeSeriesConsumer interface {
+	// ConsumeTimeSeries consumes a timeseries-style metric.
+	ConsumeTimeSeries(
+		ctx context.Context,
+		name string,
+		typ MetricDataType,
+		timestamp uint64,
+		value float64,
+		tags []string,
+		host string,
+	)
+}
+
+// SketchConsumer is a pkg/quantile sketch consumer.
+type SketchConsumer interface {
+	// ConsumeSketch consumes a pkg/quantile-style sketch.
+	ConsumeSketch(
+		ctx context.Context,
+		name string,
+		timestamp uint64,
+		sketch *quantile.Sketch,
+		tags []string,
+		host string,
+	)
+}
+
+// Consumer is a metrics consumer.
+type Consumer interface {
+	TimeSeriesConsumer
+	SketchConsumer
+}
+
+// HostConsumer is a hostname consumer.
+// It is an optional interface that can be implemented by a Consumer.
+type HostConsumer interface {
+	// ConsumeHost consumes a hostname.
+	ConsumeHost(host string)
+}

pkg/otlp/model/translator/hostname_provider.go

@@ -0,0 +1,31 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package translator
+
+import "context"
+
+// HostnameProvider gets a hostname
+type HostnameProvider interface {
+	// Hostname gets the hostname from the machine.
+	Hostname(ctx context.Context) (string, error)
+}
+
+var _ HostnameProvider = (*noHostProvider)(nil)
+
+type noHostProvider struct{}
+
+func (*noHostProvider) Hostname(context.Context) (string, error) {
+	return "", nil
+}