[pkg/otlp] Use resourcetotelemetry when ResourceAttributesAsTags is t…

…rue (DataDog#9982)

Wraps the internal metrics exporter with resourcetotelemetry to automatically convert resource attributes into tags when ResourceAttributesAsTags is true.

.copyright-overrides.yml

@@ -24,6 +24,7 @@ github.com/google/go-cmp/*: The Go Authors
 github.com/grpc-ecosystem/*: Gengo, Inc
 github.com/hashicorp/*: HashiCorp Inc.
 github.com/prometheus/*: The Prometheus Authors
+github.com/open-telemetry/*: Open Telemetry Maintainers
 go.etcd.io/*: the etcd maintainers
 google.golang.org/appengine: the Go App Engine Maintainers
 google.golang.org/appengine/*: the Go App Engine Maintainers

LICENSE-3rdparty.csv

@@ -570,6 +570,7 @@ core,github.com/open-policy-agent/opa/topdown/print,Apache-2.0,The OPA Authors
 core,github.com/open-policy-agent/opa/types,Apache-2.0,The OPA Authors
 core,github.com/open-policy-agent/opa/util,Apache-2.0,The OPA Authors
 core,github.com/open-policy-agent/opa/version,Apache-2.0,The OPA Authors
+core,github.com/open-telemetry/opentelemetry-collector-contrib/pkg/resourcetotelemetry,Apache-2.0,Open Telemetry Maintainers
 core,github.com/opencontainers/go-digest,Apache-2.0,"Docker, Inc | OCI Contributors"
 core,github.com/opencontainers/image-spec/identity,Apache-2.0,The Linux Foundation
 core,github.com/opencontainers/image-spec/specs-go,Apache-2.0,The Linux Foundation

go.mod

@@ -163,6 +163,7 @@ require (
 	github.com/olekukonko/tablewriter v0.0.5
 	github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852 // indirect
 	github.com/open-policy-agent/opa v0.34.2
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/resourcetotelemetry v0.38.0
 	github.com/opencontainers/runtime-spec v1.0.3-0.20210326190908-1c3f411f0417
 	github.com/openshift/api v0.0.0-20190924102528-32369d4db2ad
 	github.com/patrickmn/go-cache v2.1.0+incompatible

pkg/otlp/internal/serializerexporter/factory.go

@@ -9,6 +9,7 @@ import (
 	"context"
 
 	"github.com/DataDog/datadog-agent/pkg/serializer"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/resourcetotelemetry"
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
@@ -42,8 +43,14 @@ func (f *factory) createMetricExporter(_ context.Context, params component.Expor
 		return nil, err
 	}
 
-	return exporterhelper.NewMetricsExporter(cfg, params, exp.ConsumeMetrics,
+	exporter, err := exporterhelper.NewMetricsExporter(cfg, params, exp.ConsumeMetrics,
 		exporterhelper.WithQueue(cfg.QueueSettings),
 		exporterhelper.WithTimeout(cfg.TimeoutSettings),
 	)
+	if err != nil {
+		return nil, err
+	}
+
+	return resourcetotelemetry.WrapMetricsExporter(
+		resourcetotelemetry.Settings{Enabled: cfg.Metrics.ExporterConfig.ResourceAttributesAsTags}, exporter), nil
 }