Update trace API config creation functions (open-telemetry#2212)

* Update trace API config creation funcs

Follow our style guide and return the config struct instead of pointers.

* Update changelog with changes

Co-authored-by: Anthony Mirabella <a9@aneurysm9.com>

CHANGELOG.md

@@ -20,6 +20,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Metric SDK/API implementation type `InstrumentKind` moves into `sdkapi` sub-package. (#2091)
 - The Metrics SDK export record no longer contains a Resource pointer, the SDK `"go.opentelemetry.io/otel/sdk/trace/export/metric".Exporter.Export()` function for push-based exporters now takes a single Resource argument, pull-based exporters use `"go.opentelemetry.io/otel/sdk/metric/controller/basic".Controller.Resource()`. (#2120)
 - The JSON output of the `go.opentelemetry.io/otel/exporters/stdout/stdouttrace` is harmonized now such that the output is "plain" JSON objects after each other of the form `{ ... } { ... } { ... }`. Earlier the JSON objects describing a span were wrapped in a slice for each `Exporter.ExportSpans` call, like `[ { ... } ][ { ... } { ... } ]`. Outputting JSON object directly after each other is consistent with JSON loggers, and a bit easier to parse and read. (#2196)
+- Update the `NewTracerConfig`, `NewSpanStartConfig`, `NewSpanEndConfig`, and `NewEventConfig` function in the `go.opentelemetry.io/otel/trace` package to return their respective configurations as structs instead of pointers to the struct. (#2212)
 
 ### Deprecated
 

bridge/opencensus/internal/span_test.go

@@ -151,7 +151,8 @@ func TestSpanAnnotate(t *testing.T) {
 		t.Error("span.Annotate did not set event name")
 	}
 
-	got := trace.NewEventConfig(s.eOpts...).Attributes()
+	config := trace.NewEventConfig(s.eOpts...)
+	got := config.Attributes()
 	if len(want) != len(got) || want[0] != got[0] {
 		t.Error("span.Annotate did not set event options")
 	}
@@ -174,7 +175,8 @@ func TestSpanAnnotatef(t *testing.T) {
 		t.Error("span.Annotatef did not set event name")
 	}
 
-	got := trace.NewEventConfig(s.eOpts...).Attributes()
+	config := trace.NewEventConfig(s.eOpts...)
+	got := config.Attributes()
 	if len(want) != len(got) || want[0] != got[0] {
 		t.Error("span.Annotatef did not set event options")
 	}
@@ -192,7 +194,8 @@ func TestSpanAddMessageSendEvent(t *testing.T) {
 		t.Error("span.AddMessageSendEvent did not set event name")
 	}
 
-	got := trace.NewEventConfig(s.eOpts...).Attributes()
+	config := trace.NewEventConfig(s.eOpts...)
+	got := config.Attributes()
 	if len(got) != 2 {
 		t.Fatalf("span.AddMessageSendEvent set %d attributes, want 2", len(got))
 	}
@@ -220,7 +223,8 @@ func TestSpanAddMessageReceiveEvent(t *testing.T) {
 		t.Error("span.AddMessageReceiveEvent did not set event name")
 	}
 
-	got := trace.NewEventConfig(s.eOpts...).Attributes()
+	config := trace.NewEventConfig(s.eOpts...)
+	got := config.Attributes()
 	if len(got) != 2 {
 		t.Fatalf("span.AddMessageReceiveEvent set %d attributes, want 2", len(got))
 	}

bridge/opentracing/internal/mock.go

@@ -75,7 +75,7 @@ func (t *MockTracer) Start(ctx context.Context, name string, opts ...trace.SpanS
 		startTime = time.Now()
 	}
 	spanContext := trace.NewSpanContext(trace.SpanContextConfig{
-		TraceID:    t.getTraceID(ctx, config),
+		TraceID:    t.getTraceID(ctx, &config),
 		SpanID:     t.getSpanID(),
 		TraceFlags: 0,
 	})
@@ -86,7 +86,7 @@ func (t *MockTracer) Start(ctx context.Context, name string, opts ...trace.SpanS
 		Attributes:     config.Attributes(),
 		StartTime:      startTime,
 		EndTime:        time.Time{},
-		ParentSpanID:   t.getParentSpanID(ctx, config),
+		ParentSpanID:   t.getParentSpanID(ctx, &config),
 		Events:         nil,
 		SpanKind:       trace.ValidateSpanKind(config.SpanKind()),
 	}

internal/global/trace.go

@@ -90,9 +90,10 @@ func (p *tracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.T
 
 	// At this moment it is guaranteed that no sdk is installed, save the tracer in the tracers map.
 
+	c := trace.NewTracerConfig(opts...)
 	key := il{
 		name:    name,
-		version: trace.NewTracerConfig(opts...).InstrumentationVersion(),
+		version: c.InstrumentationVersion(),
 	}
 
 	if p.tracers == nil {

sdk/trace/tracer.go

@@ -46,7 +46,7 @@ func (tr *tracer) Start(ctx context.Context, name string, options ...trace.SpanS
 		}
 	}
 
-	span := startSpanInternal(ctx, tr, name, config)
+	span := startSpanInternal(ctx, tr, name, &config)
 	for _, l := range config.Links() {
 		span.addLink(l)
 	}

trace/config.go

@@ -38,10 +38,10 @@ func (t *TracerConfig) SchemaURL() string {
 }
 
 // NewTracerConfig applies all the options to a returned TracerConfig.
-func NewTracerConfig(options ...TracerOption) *TracerConfig {
-	config := new(TracerConfig)
+func NewTracerConfig(options ...TracerOption) TracerConfig {
+	var config TracerConfig
 	for _, option := range options {
-		option.apply(config)
+		option.apply(&config)
 	}
 	return config
 }
@@ -103,10 +103,10 @@ func (cfg *SpanConfig) SpanKind() SpanKind {
 // No validation is performed on the returned SpanConfig (e.g. no uniqueness
 // checking or bounding of data), it is left to the SDK to perform this
 // action.
-func NewSpanStartConfig(options ...SpanStartOption) *SpanConfig {
-	c := new(SpanConfig)
+func NewSpanStartConfig(options ...SpanStartOption) SpanConfig {
+	var c SpanConfig
 	for _, option := range options {
-		option.applySpanStart(c)
+		option.applySpanStart(&c)
 	}
 	return c
 }
@@ -115,10 +115,10 @@ func NewSpanStartConfig(options ...SpanStartOption) *SpanConfig {
 // No validation is performed on the returned SpanConfig (e.g. no uniqueness
 // checking or bounding of data), it is left to the SDK to perform this
 // action.
-func NewSpanEndConfig(options ...SpanEndOption) *SpanConfig {
-	c := new(SpanConfig)
+func NewSpanEndConfig(options ...SpanEndOption) SpanConfig {
+	var c SpanConfig
 	for _, option := range options {
-		option.applySpanEnd(c)
+		option.applySpanEnd(&c)
 	}
 	return c
 }
@@ -167,10 +167,10 @@ func (cfg *EventConfig) StackTrace() bool {
 // timestamp option is passed, the returned EventConfig will have a Timestamp
 // set to the call time, otherwise no validation is performed on the returned
 // EventConfig.
-func NewEventConfig(options ...EventOption) *EventConfig {
-	c := new(EventConfig)
+func NewEventConfig(options ...EventOption) EventConfig {
+	var c EventConfig
 	for _, option := range options {
-		option.applyEvent(c)
+		option.applyEvent(&c)
 	}
 	if c.timestamp.IsZero() {
 		c.timestamp = time.Now()

trace/config_test.go

@@ -42,18 +42,18 @@ func TestNewSpanConfig(t *testing.T) {
 
 	tests := []struct {
 		options  []SpanStartOption
-		expected *SpanConfig
+		expected SpanConfig
 	}{
 		{
 			// No non-zero-values should be set.
 			[]SpanStartOption{},
-			new(SpanConfig),
+			SpanConfig{},
 		},
 		{
 			[]SpanStartOption{
 				WithAttributes(k1v1),
 			},
-			&SpanConfig{
+			SpanConfig{
 				attributes: []attribute.KeyValue{k1v1},
 			},
 		},
@@ -64,7 +64,7 @@ func TestNewSpanConfig(t *testing.T) {
 				WithAttributes(k1v2),
 				WithAttributes(k2v2),
 			},
-			&SpanConfig{
+			SpanConfig{
 				// No uniqueness is guaranteed by the API.
 				attributes: []attribute.KeyValue{k1v1, k1v2, k2v2},
 			},
@@ -73,7 +73,7 @@ func TestNewSpanConfig(t *testing.T) {
 			[]SpanStartOption{
 				WithAttributes(k1v1, k1v2, k2v2),
 			},
-			&SpanConfig{
+			SpanConfig{
 				// No uniqueness is guaranteed by the API.
 				attributes: []attribute.KeyValue{k1v1, k1v2, k2v2},
 			},
@@ -82,7 +82,7 @@ func TestNewSpanConfig(t *testing.T) {
 			[]SpanStartOption{
 				WithTimestamp(timestamp0),
 			},
-			&SpanConfig{
+			SpanConfig{
 				timestamp: timestamp0,
 			},
 		},
@@ -92,15 +92,15 @@ func TestNewSpanConfig(t *testing.T) {
 				WithTimestamp(timestamp0),
 				WithTimestamp(timestamp1),
 			},
-			&SpanConfig{
+			SpanConfig{
 				timestamp: timestamp1,
 			},
 		},
 		{
 			[]SpanStartOption{
 				WithLinks(link1),
 			},
-			&SpanConfig{
+			SpanConfig{
 				links: []Link{link1},
 			},
 		},
@@ -110,7 +110,7 @@ func TestNewSpanConfig(t *testing.T) {
 				WithLinks(link1),
 				WithLinks(link1, link2),
 			},
-			&SpanConfig{
+			SpanConfig{
 				// No uniqueness is guaranteed by the API.
 				links: []Link{link1, link1, link2},
 			},
@@ -119,7 +119,7 @@ func TestNewSpanConfig(t *testing.T) {
 			[]SpanStartOption{
 				WithNewRoot(),
 			},
-			&SpanConfig{
+			SpanConfig{
 				newRoot: true,
 			},
 		},
@@ -129,15 +129,15 @@ func TestNewSpanConfig(t *testing.T) {
 				WithNewRoot(),
 				WithNewRoot(),
 			},
-			&SpanConfig{
+			SpanConfig{
 				newRoot: true,
 			},
 		},
 		{
 			[]SpanStartOption{
 				WithSpanKind(SpanKindConsumer),
 			},
-			&SpanConfig{
+			SpanConfig{
 				spanKind: SpanKindConsumer,
 			},
 		},
@@ -147,7 +147,7 @@ func TestNewSpanConfig(t *testing.T) {
 				WithSpanKind(SpanKindClient),
 				WithSpanKind(SpanKindConsumer),
 			},
-			&SpanConfig{
+			SpanConfig{
 				spanKind: SpanKindConsumer,
 			},
 		},
@@ -160,7 +160,7 @@ func TestNewSpanConfig(t *testing.T) {
 				WithNewRoot(),
 				WithSpanKind(SpanKindConsumer),
 			},
-			&SpanConfig{
+			SpanConfig{
 				attributes: []attribute.KeyValue{k1v1},
 				timestamp:  timestamp0,
 				links:      []Link{link1, link2},
@@ -179,25 +179,25 @@ func TestEndSpanConfig(t *testing.T) {
 
 	tests := []struct {
 		options  []SpanEndOption
-		expected *SpanConfig
+		expected SpanConfig
 	}{
 		{
 			[]SpanEndOption{},
-			new(SpanConfig),
+			SpanConfig{},
 		},
 		{
 			[]SpanEndOption{
 				WithStackTrace(true),
 			},
-			&SpanConfig{
+			SpanConfig{
 				stackTrace: true,
 			},
 		},
 		{
 			[]SpanEndOption{
 				WithTimestamp(timestamp),
 			},
-			&SpanConfig{
+			SpanConfig{
 				timestamp: timestamp,
 			},
 		},
@@ -213,18 +213,18 @@ func TestTracerConfig(t *testing.T) {
 	schemaURL := "https://opentelemetry.io/schemas/1.2.0"
 	tests := []struct {
 		options  []TracerOption
-		expected *TracerConfig
+		expected TracerConfig
 	}{
 		{
 			// No non-zero-values should be set.
 			[]TracerOption{},
-			new(TracerConfig),
+			TracerConfig{},
 		},
 		{
 			[]TracerOption{
 				WithInstrumentationVersion(v1),
 			},
-			&TracerConfig{
+			TracerConfig{
 				instrumentationVersion: v1,
 			},
 		},
@@ -234,15 +234,15 @@ func TestTracerConfig(t *testing.T) {
 				WithInstrumentationVersion(v1),
 				WithInstrumentationVersion(v2),
 			},
-			&TracerConfig{
+			TracerConfig{
 				instrumentationVersion: v2,
 			},
 		},
 		{
 			[]TracerOption{
 				WithSchemaURL(schemaURL),
 			},
-			&TracerConfig{
+			TracerConfig{
 				schemaURL: schemaURL,
 			},
 		},