Replace immutable TraceState with a mutable struct (#6052)

* Replace immutable TraceState with a mutable struct

Fixes #6022

Main motivation is that we may want to allow mutating (adding an entry to the state).

Signed-off-by: Bogdan <[email protected]>

* Update CHANGELOG.md

Co-authored-by: Dmitrii Anoshin <[email protected]>

Signed-off-by: Bogdan <[email protected]>
Co-authored-by: Dmitrii Anoshin <[email protected]>

CHANGELOG.md

@@ -96,6 +96,12 @@
   - `SummaryDataPoint.Flags` -> `SummaryDataPoint.FlagsImmutable`
   - `MetricDataPointFlags` -> `MetricDataPointFlagsImmutable`
   - `NewMetricDataPointFlags` -> `MetricDataPointFlagsImmutable`
+- Deprecate `ptrace.TraceState` in favor of `pcommon.TraceState`. (#6052)
+  - `ptrace.Span.TraceState` in favor of `ptrace.Span.TraceStateStruct().AsRaw()`
+  - `ptrace.Span.SetTraceState` in favor of `ptrace.Span.TraceStateStruct().FromRaw`
+  - `ptrace.SpanLink.TraceState` in favor of `ptrace.SpanLink.TraceStateStruct().AsRaw()`
+  - `ptrace.SpanLink.SetTraceState` in favor of `ptrace.SpanLink.TraceStateStruct().FromRaw`
+  - `TraceStateStruct` is a temporary name that will be replaced back to `TraceState` in the next release.
 
 ### 💡 Enhancements 💡
 

exporter/loggingexporter/internal/otlptext/databuffer.go

@@ -257,7 +257,7 @@ func (b *dataBuffer) logLinks(description string, sl ptrace.SpanLinkSlice) {
 		b.logEntry("SpanLink #%d", i)
 		b.logEntry("     -> Trace ID: %s", l.TraceID().HexString())
 		b.logEntry("     -> ID: %s", l.SpanID().HexString())
-		b.logEntry("     -> TraceState: %s", l.TraceState())
+		b.logEntry("     -> TraceState: %s", l.TraceStateStruct().AsRaw())
 		b.logEntry("     -> DroppedAttributesCount: %d", l.DroppedAttributesCount())
 		if l.Attributes().Len() == 0 {
 			continue

pdata/internal/cmd/pdatagen/internal/common_structs.go

@@ -72,6 +72,11 @@ var scopeField = &messageValueField{
 	returnMessage:   scope,
 }
 
+var traceState = &messageValueStruct{
+	structName:  "TraceState",
+	packageName: "pcommon",
+}
+
 var timestampType = &primitiveType{
 	structName:  "Timestamp",
 	packageName: "pcommon",

pdata/internal/cmd/pdatagen/internal/trace_structs.go

@@ -213,15 +213,10 @@ var spanStatus = &messageValueStruct{
 	},
 }
 
-var traceStateField = &primitiveTypedField{
-	fieldName:       "TraceState",
+var traceStateField = &messageValueField{
+	fieldName:       "TraceStateStruct",
 	originFieldName: "TraceState",
-	returnType: &primitiveType{
-		structName: "TraceState",
-		rawType:    "string",
-		defaultVal: `""`,
-		testVal:    `"congo=congos"`,
-	},
+	returnMessage:   traceState,
 }
 
 var droppedAttributesCount = &primitiveField{

pdata/internal/wrapper_common.go

@@ -30,6 +30,17 @@ func NewValue(orig *otlpcommon.AnyValue) Value {
 	return Value{orig: orig}
 }
 
+func FillTestValue(dest Value) {
+	dest.orig.Value = &otlpcommon.AnyValue_StringValue{StringValue: "v"}
+}
+
+func GenerateTestValue() Value {
+	var orig otlpcommon.AnyValue
+	ms := NewValue(&orig)
+	FillTestValue(ms)
+	return ms
+}
+
 type Map struct {
 	orig *[]otlpcommon.KeyValue
 }
@@ -42,25 +53,37 @@ func NewMap(orig *[]otlpcommon.KeyValue) Map {
 	return Map{orig: orig}
 }
 
-func FillTestValue(dest Value) {
-	dest.orig.Value = &otlpcommon.AnyValue_StringValue{StringValue: "v"}
-}
-
-func GenerateTestValue() Value {
-	var orig otlpcommon.AnyValue
-	av := NewValue(&orig)
-	FillTestValue(av)
-	return av
-}
-
 func GenerateTestMap() Map {
 	var orig []otlpcommon.KeyValue
-	am := NewMap(&orig)
-	FillTestMap(am)
-	return am
+	ms := NewMap(&orig)
+	FillTestMap(ms)
+	return ms
 }
 
 func FillTestMap(dest Map) {
 	*dest.orig = nil
 	*dest.orig = append(*dest.orig, otlpcommon.KeyValue{Key: "k", Value: otlpcommon.AnyValue{Value: &otlpcommon.AnyValue_StringValue{StringValue: "v"}}})
 }
+
+type TraceState struct {
+	orig *string
+}
+
+func GetOrigTraceState(ms TraceState) *string {
+	return ms.orig
+}
+
+func NewTraceState(orig *string) TraceState {
+	return TraceState{orig: orig}
+}
+
+func GenerateTestTraceState() TraceState {
+	var orig string
+	ms := NewTraceState(&orig)
+	FillTestTraceState(ms)
+	return ms
+}
+
+func FillTestTraceState(dest TraceState) {
+	*dest.orig = "rojo=00f067aa0ba902b7"
+}

pdata/pcommon/trace_state.go

@@ -0,0 +1,51 @@
+// 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 pcommon // import "go.opentelemetry.io/collector/pdata/pcommon"
+
+import (
+	"go.opentelemetry.io/collector/pdata/internal"
+)
+
+// TraceState represents the trace state from the w3c-trace-context.
+type TraceState internal.TraceState
+
+func NewTraceState() TraceState {
+	return TraceState(internal.NewTraceState(new(string)))
+}
+
+func (ms TraceState) getOrig() *string {
+	return internal.GetOrigTraceState(internal.TraceState(ms))
+}
+
+// AsRaw returns the string representation of the tracestate in w3c-trace-context format: https://www.w3.org/TR/trace-context/#tracestate-header
+func (ms TraceState) AsRaw() string {
+	return *ms.getOrig()
+}
+
+// FromRaw copies the string representation in w3c-trace-context format of the tracestate into this TraceState.
+func (ms TraceState) FromRaw(v string) {
+	*ms.getOrig() = v
+}
+
+// MoveTo moves TraceState to another instance.
+func (ms TraceState) MoveTo(dest TraceState) {
+	*dest.getOrig() = *ms.getOrig()
+	*ms.getOrig() = ""
+}
+
+// CopyTo copies TraceState to another instance.
+func (ms TraceState) CopyTo(dest TraceState) {
+	*dest.getOrig() = *ms.getOrig()
+}

pdata/pcommon/trace_state_test.go

@@ -0,0 +1,48 @@
+// 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 pcommon
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/collector/pdata/internal"
+)
+
+func TestTraceState_MoveTo(t *testing.T) {
+	ms := TraceState(internal.GenerateTestTraceState())
+	dest := NewTraceState()
+	ms.MoveTo(dest)
+	assert.Equal(t, NewTraceState(), ms)
+	assert.Equal(t, TraceState(internal.GenerateTestTraceState()), dest)
+}
+
+func TestTraceState_CopyTo(t *testing.T) {
+	ms := NewTraceState()
+	orig := NewTraceState()
+	orig.CopyTo(ms)
+	assert.Equal(t, orig, ms)
+	orig = TraceState(internal.GenerateTestTraceState())
+	orig.CopyTo(ms)
+	assert.Equal(t, orig, ms)
+}
+
+func TestTraceState_FromRaw_AsRaw(t *testing.T) {
+	ms := NewTraceState()
+	assert.Equal(t, "", ms.AsRaw())
+	ms.FromRaw("congo=t61rcWkgMzE")
+	assert.Equal(t, "congo=t61rcWkgMzE", ms.AsRaw())
+}

pdata/ptrace/json_test.go

@@ -84,7 +84,7 @@ var tracesOTLPFull = func() Traces {
 	sp.SetDroppedLinksCount(1)
 	sp.SetEndTimestamp(pcommon.NewTimestampFromTime(time.Now()))
 	sp.SetParentSpanID(spanID)
-	sp.SetTraceState("state")
+	sp.TraceStateStruct().FromRaw("state")
 	sp.Status().SetCode(StatusCodeOk)
 	sp.Status().SetMessage("message")
 	// Add attributes.
@@ -111,7 +111,7 @@ var tracesOTLPFull = func() Traces {
 	event.Attributes().UpsertEmptyBytes("bytes").FromRaw([]byte("foo"))
 	// Add links.
 	link := sp.Links().AppendEmpty()
-	link.SetTraceState("state")
+	link.TraceStateStruct().FromRaw("state")
 	link.SetTraceID(traceID)
 	link.SetSpanID(spanID)
 	link.SetDroppedAttributesCount(1)

pdata/ptrace/traces.go

@@ -70,14 +70,34 @@ func (ms Traces) ResourceSpans() ResourceSpansSlice {
 	return newResourceSpansSlice(&ms.getOrig().ResourceSpans)
 }
 
-// TraceState is a string representing the tracestate in w3c-trace-context format: https://www.w3.org/TR/trace-context/#tracestate-header
+// Deprecated: [v0.60.0] use pcommon.TraceState.
 type TraceState string
 
 const (
-	// TraceStateEmpty represents the empty TraceState.
+	// Deprecated: [v0.60.0] use pcommon.TraceState.AsRaw() and compare with empty string.
 	TraceStateEmpty TraceState = ""
 )
 
+// Deprecated: [v0.60.0] use TraceStateStruct().AsRaw().
+func (ms Span) TraceState() TraceState {
+	return TraceState(ms.getOrig().TraceState)
+}
+
+// Deprecated: [v0.60.0] use TraceStateStruct().FromRaw(val).
+func (ms Span) SetTraceState(v TraceState) {
+	ms.getOrig().TraceState = string(v)
+}
+
+// Deprecated: [v0.60.0] use TraceStateStruct().AsRaw().
+func (ms SpanLink) TraceState() TraceState {
+	return TraceState(ms.getOrig().TraceState)
+}
+
+// Deprecated: [v0.60.0] use TraceStateStruct().FromRaw(val).
+func (ms SpanLink) SetTraceState(v TraceState) {
+	ms.getOrig().TraceState = string(v)
+}
+
 // SpanKind is the type of span. Can be used to specify additional relationships between spans
 // in addition to a parent/child relationship.
 type SpanKind int32