[chore] [receiver/datadog] Refactor translation files into internal p…

…ackage (open-telemetry#34160)

**Description:**
This PR is a follow-up to open-telemetry#33957. It refactors the Datadog receiver
files to remove internal methods and structures from the public API and
into an internal directory.

**Link to tracking Issue:** 
open-telemetry#18278 

**Testing:** 
This is a refactor, so no new unit tests have been added.

receiver/datadogreceiver/batcher.go → receiver/datadogreceiver/internal/translator/batcher.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
 
 import (
 	"go.opentelemetry.io/collector/pdata/pcommon"
@@ -10,16 +10,16 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/exp/metrics/identity"
 )
 
-type Batcher struct {
+type batcher struct {
 	pmetric.Metrics
 
 	resourceMetrics map[identity.Resource]pmetric.ResourceMetrics
 	scopeMetrics    map[identity.Scope]pmetric.ScopeMetrics
 	metrics         map[identity.Metric]pmetric.Metric
 }
 
-func newBatcher() Batcher {
-	return Batcher{
+func newBatcher() batcher {
+	return batcher{
 		Metrics:         pmetric.NewMetrics(),
 		resourceMetrics: make(map[identity.Resource]pmetric.ResourceMetrics),
 		scopeMetrics:    make(map[identity.Scope]pmetric.ScopeMetrics),
@@ -30,7 +30,7 @@ func newBatcher() Batcher {
 // Dimensions stores the properties of the series that are needed in order
 // to unique identify the series. This is needed in order to batch metrics by
 // resource, scope, and datapoint attributes
-type Dimensions struct {
+type dimensions struct {
 	name          string
 	metricType    pmetric.MetricType
 	resourceAttrs pcommon.Map
@@ -47,9 +47,9 @@ var metricTypeMap = map[string]pmetric.MetricType{
 	"sketch":        pmetric.MetricTypeExponentialHistogram,
 }
 
-func parseSeriesProperties(name string, metricType string, tags []string, host string, version string, stringPool *StringPool) Dimensions {
+func parseSeriesProperties(name string, metricType string, tags []string, host string, version string, stringPool *StringPool) dimensions {
 	resourceAttrs, scopeAttrs, dpAttrs := tagsToAttributes(tags, host, stringPool)
-	return Dimensions{
+	return dimensions{
 		name:          name,
 		metricType:    metricTypeMap[metricType],
 		buildInfo:     version,
@@ -59,7 +59,7 @@ func parseSeriesProperties(name string, metricType string, tags []string, host s
 	}
 }
 
-func (b Batcher) Lookup(dim Dimensions) (pmetric.Metric, identity.Metric) {
+func (b batcher) Lookup(dim dimensions) (pmetric.Metric, identity.Metric) {
 	resource := dim.Resource()
 	resourceID := identity.OfResource(resource)
 	resourceMetrics, ok := b.resourceMetrics[resourceID]
@@ -90,21 +90,21 @@ func (b Batcher) Lookup(dim Dimensions) (pmetric.Metric, identity.Metric) {
 	return metric, metricID
 }
 
-func (d Dimensions) Resource() pcommon.Resource {
+func (d dimensions) Resource() pcommon.Resource {
 	resource := pcommon.NewResource()
 	d.resourceAttrs.CopyTo(resource.Attributes()) // TODO(jesus.vazquez) review this copy
 	return resource
 }
 
-func (d Dimensions) Scope() pcommon.InstrumentationScope {
+func (d dimensions) Scope() pcommon.InstrumentationScope {
 	scope := pcommon.NewInstrumentationScope()
 	scope.SetName("otelcol/datadogreceiver")
 	scope.SetVersion(d.buildInfo)
 	d.scopeAttrs.CopyTo(scope.Attributes())
 	return scope
 }
 
-func (d Dimensions) Metric() pmetric.Metric {
+func (d dimensions) Metric() pmetric.Metric {
 	metric := pmetric.NewMetric()
 	metric.SetName(d.name)
 	switch d.metricType {

receiver/datadogreceiver/batcher_test.go → receiver/datadogreceiver/internal/translator/batcher_test.go

@@ -1,14 +1,13 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver
+package translator
 
 import (
 	"testing"
 
 	"github.com/DataDog/datadog-api-client-go/v2/api/datadogV1"
 	"github.com/stretchr/testify/require"
-	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pdata/pmetric"
 )
 
@@ -275,13 +274,8 @@ func TestMetricBatcher(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			mt := newMetricsTranslator()
-			mt.buildInfo = component.BuildInfo{
-				Command:     "otelcol",
-				Description: "OpenTelemetry Collector",
-				Version:     "latest",
-			}
-			result := mt.translateMetricsV1(tt.series)
+			mt := createMetricsTranslator()
+			result := mt.TranslateSeriesV1(tt.series)
 
 			tt.expect(t, result)
 		})

receiver/datadogreceiver/internal/translator/metrics_translator.go

@@ -0,0 +1,41 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
+
+import (
+	"sync"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/pdata/pcommon"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/exp/metrics/identity"
+)
+
+type MetricsTranslator struct {
+	sync.RWMutex
+	buildInfo  component.BuildInfo
+	lastTs     map[identity.Stream]pcommon.Timestamp
+	stringPool *StringPool
+}
+
+func NewMetricsTranslator(buildInfo component.BuildInfo) *MetricsTranslator {
+	return &MetricsTranslator{
+		buildInfo:  buildInfo,
+		lastTs:     make(map[identity.Stream]pcommon.Timestamp),
+		stringPool: newStringPool(),
+	}
+}
+
+func (mt *MetricsTranslator) streamHasTimestamp(stream identity.Stream) (pcommon.Timestamp, bool) {
+	mt.RLock()
+	defer mt.RUnlock()
+	ts, ok := mt.lastTs[stream]
+	return ts, ok
+}
+
+func (mt *MetricsTranslator) updateLastTsForStream(stream identity.Stream, ts pcommon.Timestamp) {
+	mt.Lock()
+	defer mt.Unlock()
+	mt.lastTs[stream] = ts
+}

receiver/datadogreceiver/metrics_translator.go → receiver/datadogreceiver/internal/translator/series.go

@@ -1,47 +1,18 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
 
 import (
-	"sync"
 	"time"
 
 	datadogV1 "github.com/DataDog/datadog-api-client-go/v2/api/datadogV1"
-	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/pmetric"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/exp/metrics/identity"
 )
 
-type MetricsTranslator struct {
-	sync.RWMutex
-	buildInfo  component.BuildInfo
-	lastTs     map[identity.Stream]pcommon.Timestamp
-	stringPool *StringPool
-}
-
-func newMetricsTranslator() *MetricsTranslator {
-	return &MetricsTranslator{
-		lastTs:     make(map[identity.Stream]pcommon.Timestamp),
-		stringPool: newStringPool(),
-	}
-}
-
-func (mt *MetricsTranslator) streamHasTimestamp(stream identity.Stream) (pcommon.Timestamp, bool) {
-	mt.RLock()
-	defer mt.RUnlock()
-	ts, ok := mt.lastTs[stream]
-	return ts, ok
-}
-
-func (mt *MetricsTranslator) updateLastTsForStream(stream identity.Stream, ts pcommon.Timestamp) {
-	mt.Lock()
-	defer mt.Unlock()
-	mt.lastTs[stream] = ts
-}
-
 const (
 	TypeGauge string = "gauge"
 	TypeRate  string = "rate"
@@ -52,7 +23,7 @@ type SeriesList struct {
 	Series []datadogV1.Series `json:"series"`
 }
 
-func (mt *MetricsTranslator) translateMetricsV1(series SeriesList) pmetric.Metrics {
+func (mt *MetricsTranslator) TranslateSeriesV1(series SeriesList) pmetric.Metrics {
 	bt := newBatcher()
 
 	for _, serie := range series.Series {

receiver/datadogreceiver/metrics_translator_test.go → receiver/datadogreceiver/internal/translator/series_test.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver
+package translator
 
 import (
 	"testing"
@@ -28,7 +28,7 @@ func testPointsToDatadogPoints(points []testPoint) [][]*float64 {
 
 }
 
-func TestTranslateMetricsV1(t *testing.T) {
+func TestTranslateSeriesV1(t *testing.T) {
 	tests := []struct {
 		name string
 
@@ -152,7 +152,7 @@ func TestTranslateMetricsV1(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			mt := createMetricsTranslator()
-			result := mt.translateMetricsV1(tt.series)
+			result := mt.TranslateSeriesV1(tt.series)
 
 			tt.expect(t, result)
 		})

receiver/datadogreceiver/tags.go → receiver/datadogreceiver/internal/translator/tags.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
 
 import (
 	"fmt"

receiver/datadogreceiver/tags_test.go → receiver/datadogreceiver/internal/translator/tags_test.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver
+package translator
 
 import (
 	"testing"

receiver/datadogreceiver/testutil.go → receiver/datadogreceiver/internal/translator/testutil.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
 
 import (
 	"testing"
@@ -13,12 +13,11 @@ import (
 )
 
 func createMetricsTranslator() *MetricsTranslator {
-	mt := newMetricsTranslator()
-	mt.buildInfo = component.BuildInfo{
+	mt := NewMetricsTranslator(component.BuildInfo{
 		Command:     "otelcol",
 		Description: "OpenTelemetry Collector",
 		Version:     "latest",
-	}
+	})
 	return mt
 }
 

receiver/datadogreceiver/traces_translator.go → receiver/datadogreceiver/internal/translator/traces_translator.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package datadogreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver"
+package translator // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/datadogreceiver/internal/translator"
 
 import (
 	"bytes"
@@ -51,7 +51,7 @@ func upsertHeadersAttributes(req *http.Request, attrs pcommon.Map) {
 	}
 }
 
-func toTraces(payload *pb.TracerPayload, req *http.Request) ptrace.Traces {
+func ToTraces(payload *pb.TracerPayload, req *http.Request) ptrace.Traces {
 	var traces pb.Traces
 	for _, p := range payload.GetChunks() {
 		traces = append(traces, p.GetSpans())
@@ -161,17 +161,17 @@ var bufferPool = sync.Pool{
 	},
 }
 
-func getBuffer() *bytes.Buffer {
+func GetBuffer() *bytes.Buffer {
 	buffer := bufferPool.Get().(*bytes.Buffer)
 	buffer.Reset()
 	return buffer
 }
 
-func putBuffer(buffer *bytes.Buffer) {
+func PutBuffer(buffer *bytes.Buffer) {
 	bufferPool.Put(buffer)
 }
 
-func handleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error) {
+func HandleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error) {
 	var tracerPayloads []*pb.TracerPayload
 
 	defer func() {
@@ -181,8 +181,8 @@ func handleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error)
 
 	switch {
 	case strings.HasPrefix(req.URL.Path, "/v0.7"):
-		buf := getBuffer()
-		defer putBuffer(buf)
+		buf := GetBuffer()
+		defer PutBuffer(buf)
 		if _, err = io.Copy(buf, req.Body); err != nil {
 			return nil, err
 		}
@@ -193,8 +193,8 @@ func handleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error)
 
 		tracerPayloads = append(tracerPayloads, &tracerPayload)
 	case strings.HasPrefix(req.URL.Path, "/v0.5"):
-		buf := getBuffer()
-		defer putBuffer(buf)
+		buf := GetBuffer()
+		defer PutBuffer(buf)
 		if _, err = io.Copy(buf, req.Body); err != nil {
 			return nil, err
 		}
@@ -229,8 +229,8 @@ func handleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error)
 		}
 		tracerPayloads = append(tracerPayloads, tracerPayload)
 	case strings.HasPrefix(req.URL.Path, "/api/v0.2"):
-		buf := getBuffer()
-		defer putBuffer(buf)
+		buf := GetBuffer()
+		defer PutBuffer(buf)
 		if _, err = io.Copy(buf, req.Body); err != nil {
 			return nil, err
 		}
@@ -265,8 +265,8 @@ func handleTracesPayload(req *http.Request) (tp []*pb.TracerPayload, err error)
 func decodeRequest(req *http.Request, dest *pb.Traces) (err error) {
 	switch mediaType := getMediaType(req); mediaType {
 	case "application/msgpack":
-		buf := getBuffer()
-		defer putBuffer(buf)
+		buf := GetBuffer()
+		defer PutBuffer(buf)
 		_, err = io.Copy(buf, req.Body)
 		if err != nil {
 			return err
@@ -283,8 +283,8 @@ func decodeRequest(req *http.Request, dest *pb.Traces) (err error) {
 	default:
 		// do our best
 		if err1 := json.NewDecoder(req.Body).Decode(&dest); err1 != nil {
-			buf := getBuffer()
-			defer putBuffer(buf)
+			buf := GetBuffer()
+			defer PutBuffer(buf)
 			_, err2 := io.Copy(buf, req.Body)
 			if err2 != nil {
 				return err2