Make pdata.LogsToOtlp impossible to call from outside this repo

pdata.LogsToOtlp is intended to be used only by OTLP exporter (for which is the
native data format) and fileexporter (for which we do want to output internal
representation for debugging purposes).

Everyone else is supposed to use public member functions of pdata.Logs.

This changes makes it impossible to use pdata.LogsToOtlp outside this repo by
hiding it behind an intermediary struct that is declared in an internal package.

This is necessary to prevent accidental use of LogsToOtlp and the OTLP data
struct which we prohibit to do since the OTLP data structs may change in the
future.

As part of this change I had to move timestamp-related functions from internal
to pdata package (where they logically belong) to avoid circular package
references.

consumer/pdata/log.go

@@ -17,6 +17,7 @@ package pdata
 import (
 	"github.com/gogo/protobuf/proto"
 
+	"go.opentelemetry.io/collector/internal"
 	otlplogs "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/logs/v1"
 )
 
@@ -37,20 +38,21 @@ func LogsFromOtlp(orig []*otlplogs.ResourceLogs) Logs {
 	return Logs{&orig}
 }
 
-// LogsToOtlp converts the internal Logs to the ProtoBuf.
-func LogsToOtlp(ld Logs) []*otlplogs.ResourceLogs {
-	return *ld.orig
-}
-
 // NewLogs creates a new Logs.
 func NewLogs() Logs {
 	orig := []*otlplogs.ResourceLogs(nil)
 	return Logs{&orig}
 }
 
+// InternalRep returns internal representation of the logs. Should not be used outside
+// this repository.
+func (ld Logs) InternalRep() internal.OtlpLogsWrapper {
+	return internal.OtlpLogsWrapper{Orig: ld.orig}
+}
+
 // Clone returns a copy of Logs.
 func (ld Logs) Clone() Logs {
-	otlp := LogsToOtlp(ld)
+	otlp := *ld.orig
 	resourceSpansClones := make([]*otlplogs.ResourceLogs, 0, len(otlp))
 	for _, resourceSpans := range otlp {
 		resourceSpansClones = append(resourceSpansClones,

consumer/pdata/log_test.go

@@ -67,5 +67,5 @@ func TestToFromLogProto(t *testing.T) {
 	otlp := []*otlplogs.ResourceLogs(nil)
 	td := LogsFromOtlp(otlp)
 	assert.EqualValues(t, NewLogs(), td)
-	assert.EqualValues(t, otlp, LogsToOtlp(td))
+	assert.EqualValues(t, otlp, *td.orig)
 }

internal/internal.go → consumer/pdata/timestamp.go

@@ -12,32 +12,30 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package pdata
 
 import (
 	"time"
 
 	"google.golang.org/protobuf/types/known/timestamppb"
-
-	"go.opentelemetry.io/collector/consumer/pdata"
 )
 
-func TimestampToUnixNano(ts *timestamppb.Timestamp) (t pdata.TimestampUnixNano) {
+func TimestampToUnixNano(ts *timestamppb.Timestamp) (t TimestampUnixNano) {
 	if ts == nil {
 		return
 	}
-	return pdata.TimestampUnixNano(uint64(ts.AsTime().UnixNano()))
+	return TimestampUnixNano(uint64(ts.AsTime().UnixNano()))
 }
 
-func UnixNanoToTimestamp(u pdata.TimestampUnixNano) *timestamppb.Timestamp {
+func UnixNanoToTimestamp(u TimestampUnixNano) *timestamppb.Timestamp {
 	// 0 is a special case and want to make sure we return nil.
 	if u == 0 {
 		return nil
 	}
 	return timestamppb.New(UnixNanoToTime(u))
 }
 
-func UnixNanoToTime(u pdata.TimestampUnixNano) time.Time {
+func UnixNanoToTime(u TimestampUnixNano) time.Time {
 	// 0 is a special case and want to make sure we return a time that IsZero() returns true.
 	if u == 0 {
 		return time.Time{}

internal/internal_test.go → consumer/pdata/timestamp_test.go

@@ -12,21 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package internal
+package pdata
 
 import (
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
 	"google.golang.org/protobuf/types/known/timestamppb"
-
-	"go.opentelemetry.io/collector/consumer/pdata"
 )
 
 func TestUnixNanosConverters(t *testing.T) {
 	t1 := time.Date(2020, 03, 24, 1, 13, 23, 789, time.UTC)
-	tun := pdata.TimestampUnixNano(t1.UnixNano())
+	tun := TimestampUnixNano(t1.UnixNano())
 
 	assert.EqualValues(t, uint64(1585012403000000789), tun)
 	tp := UnixNanoToTimestamp(tun)

exporter/fileexporter/file_exporter.go

@@ -25,6 +25,7 @@ import (
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer/pdata"
 	"go.opentelemetry.io/collector/consumer/pdatautil"
+	"go.opentelemetry.io/collector/internal"
 	"go.opentelemetry.io/collector/internal/data"
 	otlplogs "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/collector/logs/v1"
 	otlpmetrics "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/collector/metrics/v1"
@@ -57,7 +58,7 @@ func (e *fileExporter) ConsumeMetrics(_ context.Context, md pdata.Metrics) error
 
 func (e *fileExporter) ConsumeLogs(_ context.Context, ld pdata.Logs) error {
 	request := otlplogs.ExportLogsServiceRequest{
-		ResourceLogs: pdata.LogsToOtlp(ld),
+		ResourceLogs: internal.LogsToOtlp(ld.InternalRep()),
 	}
 	return exportMessageAsLine(e, &request)
 }

exporter/otlpexporter/otlp.go

@@ -31,6 +31,7 @@ import (
 	"go.opentelemetry.io/collector/consumer/pdata"
 	"go.opentelemetry.io/collector/consumer/pdatautil"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
+	"go.opentelemetry.io/collector/internal"
 	"go.opentelemetry.io/collector/internal/data"
 	otlplogs "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/collector/logs/v1"
 	otlpmetrics "go.opentelemetry.io/collector/internal/data/opentelemetry-proto-gen/collector/metrics/v1"
@@ -104,7 +105,7 @@ func (e *exporterImp) pushMetricsData(ctx context.Context, md pdata.Metrics) (in
 
 func (e *exporterImp) pushLogData(ctx context.Context, logs pdata.Logs) (int, error) {
 	request := &otlplogs.ExportLogsServiceRequest{
-		ResourceLogs: pdata.LogsToOtlp(logs),
+		ResourceLogs: internal.LogsToOtlp(logs.InternalRep()),
 	}
 	err := e.w.exportLogs(ctx, request)