More cleanups from #100 (#142)

* Drop dead event type

* Replace EventType from reader with one from exporter

* Do not concat the strings for string buffer

* Fill scope ID in events

That required renaming a variable, because it had the same name as the
type we wanted to assert later.

* Do not fail quietly when span context is busted

experimental/streaming/exporter/exporter.go

@@ -57,7 +57,6 @@ const (
 	START_SPAN
 	FINISH_SPAN
 	ADD_EVENT
-	ADD_EVENTF
 	NEW_SCOPE
 	NEW_MEASURE
 	NEW_METRIC

experimental/streaming/exporter/reader/format/format.go

@@ -20,6 +20,7 @@ import (
 
 	"go.opentelemetry.io/api/core"
 	"go.opentelemetry.io/api/key"
+	"go.opentelemetry.io/experimental/streaming/exporter"
 	"go.opentelemetry.io/experimental/streaming/exporter/reader"
 
 	// TODO this should not be an SDK dependency; move conventional tags into the API.
@@ -37,7 +38,10 @@ func AppendEvent(buf *strings.Builder, data reader.Event) {
 			if skipIf && data.Attributes.HasValue(kv.Key) {
 				return true
 			}
-			buf.WriteString(" " + kv.Key.Name + "=" + kv.Value.Emit())
+			buf.WriteString(" ")
+			buf.WriteString(kv.Key.Name)
+			buf.WriteString("=")
+			buf.WriteString(kv.Value.Emit())
 			return true
 		}
 	}
@@ -46,7 +50,7 @@ func AppendEvent(buf *strings.Builder, data reader.Event) {
 	buf.WriteString(" ")
 
 	switch data.Type {
-	case reader.START_SPAN:
+	case exporter.START_SPAN:
 		buf.WriteString("start ")
 		buf.WriteString(data.Name)
 
@@ -61,27 +65,31 @@ func AppendEvent(buf *strings.Builder, data reader.Event) {
 			buf.WriteString(" >")
 		}
 
-	case reader.FINISH_SPAN:
+	case exporter.FINISH_SPAN:
 		buf.WriteString("finish ")
 		buf.WriteString(data.Name)
 
 		buf.WriteString(" (")
 		buf.WriteString(data.Duration.String())
 		buf.WriteString(")")
 
-	case reader.ADD_EVENT:
+	case exporter.ADD_EVENT:
 		buf.WriteString("event: ")
 		buf.WriteString(data.Message)
 		buf.WriteString(" (")
 		data.Attributes.Foreach(func(kv core.KeyValue) bool {
-			buf.WriteString(" " + kv.Key.Name + "=" + kv.Value.Emit())
+			buf.WriteString(" ")
+			buf.WriteString(kv.Key.Name)
+			buf.WriteString("=")
+			buf.WriteString(kv.Value.Emit())
 			return true
 		})
 		buf.WriteString(")")
 
-	case reader.MODIFY_ATTR:
-		buf.WriteString("modify attr")
-	case reader.RECORD_STATS:
+	case exporter.MODIFY_ATTR:
+		buf.WriteString("modify attr ")
+		buf.WriteString(data.Type.String())
+	case exporter.RECORD_STATS:
 		buf.WriteString("record")
 
 		for _, s := range data.Stats {
@@ -103,11 +111,12 @@ func AppendEvent(buf *strings.Builder, data reader.Event) {
 			})
 			buf.WriteString("}")
 		}
-	case reader.SET_STATUS:
+
+	case exporter.SET_STATUS:
 		buf.WriteString("set status ")
 		buf.WriteString(data.Status.String())
 
-	case reader.SET_NAME:
+	case exporter.SET_NAME:
 		buf.WriteString("set name ")
 		buf.WriteString(data.Name)
 

experimental/streaming/exporter/reader/reader.go

@@ -31,10 +31,8 @@ type Reader interface {
 	Read(Event)
 }
 
-type EventType int
-
 type Event struct {
-	Type        EventType
+	Type        exporter.EventType
 	Time        time.Time
 	Sequence    exporter.EventID
 	SpanContext core.SpanContext
@@ -94,17 +92,6 @@ type readerScope struct {
 	attributes tag.Map
 }
 
-const (
-	INVALID EventType = iota
-	START_SPAN
-	FINISH_SPAN
-	ADD_EVENT
-	MODIFY_ATTR
-	RECORD_STATS
-	SET_STATUS
-	SET_NAME
-)
-
 // NewReaderObserver returns an implementation that computes the
 // necessary state needed by a reader to process events in memory.
 // Practically, this means tracking live metric handles and scope
@@ -149,7 +136,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		span.readerScope.attributes = rattrs
 
 		read.Name = span.name
-		read.Type = START_SPAN
+		read.Type = exporter.START_SPAN
 		read.SpanContext = span.spanContext
 		read.Attributes = rattrs
 
@@ -177,7 +164,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		}
 
 		read.Name = span.name
-		read.Type = FINISH_SPAN
+		read.Type = exporter.FINISH_SPAN
 
 		read.Attributes = attrs
 		read.Duration = event.Time.Sub(span.start)
@@ -227,7 +214,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 			return
 		}
 
-		read.Type = MODIFY_ATTR
+		read.Type = exporter.MODIFY_ATTR
 		read.Attributes = sc.attributes
 
 		if span != nil {
@@ -254,7 +241,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		return
 
 	case exporter.ADD_EVENT:
-		read.Type = ADD_EVENT
+		read.Type = exporter.ADD_EVENT
 		read.Message = event.String
 
 		attrs, span := ro.readScope(event.Scope)
@@ -266,7 +253,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		}
 
 	case exporter.RECORD_STATS:
-		read.Type = RECORD_STATS
+		read.Type = exporter.RECORD_STATS
 
 		_, span := ro.readScope(event.Scope)
 		if span != nil {
@@ -280,7 +267,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		}
 
 	case exporter.SET_STATUS:
-		read.Type = SET_STATUS
+		read.Type = exporter.SET_STATUS
 		read.Status = event.Status
 		_, span := ro.readScope(event.Scope)
 		if span != nil {
@@ -289,7 +276,7 @@ func (ro *readerObserver) orderedObserve(event exporter.Event) {
 		}
 
 	case exporter.SET_NAME:
-		read.Type = SET_NAME
+		read.Type = exporter.SET_NAME
 		read.Name = event.String
 
 	default:

experimental/streaming/exporter/spandata/spandata.go

@@ -42,11 +42,10 @@ func NewReaderObserver(readers ...Reader) exporter.Observer {
 
 func (s *spanReader) Read(data reader.Event) {
 	if !data.SpanContext.HasSpanID() {
-		// @@@ This is happening, somehow span context is busted.
-		return
+		panic("How is this?")
 	}
 	var span *Span
-	if data.Type == reader.START_SPAN {
+	if data.Type == exporter.START_SPAN {
 		span = &Span{Events: make([]reader.Event, 0, 4)}
 		s.spans[data.SpanContext] = span
 	} else {
@@ -59,7 +58,7 @@ func (s *spanReader) Read(data reader.Event) {
 
 	span.Events = append(span.Events, data)
 
-	if data.Type == reader.FINISH_SPAN {
+	if data.Type == exporter.FINISH_SPAN {
 		for _, r := range s.readers {
 			r.Read(span)
 		}

experimental/streaming/sdk/span.go

@@ -120,6 +120,7 @@ func (sp *span) addEventWithTime(ctx context.Context, timestamp time.Time, msg s
 	sp.tracer.exporter.Record(exporter.Event{
 		Time:       timestamp,
 		Type:       exporter.ADD_EVENT,
+		Scope:      sp.ScopeID(),
 		String:     msg,
 		Attributes: attrs,
 		Context:    ctx,

experimental/streaming/sdk/span_test.go

@@ -35,14 +35,14 @@ func TestEvents(t *testing.T) {
 	_ = New(obs).WithSpan(context.Background(), "test", func(ctx context.Context) error {
 		type test1Type struct{}
 		type test2Type struct{}
-		span := trace.CurrentSpan(ctx)
+		sp := trace.CurrentSpan(ctx)
 		k1v1 := key.New("k1").String("v1")
 		k2v2 := key.New("k2").String("v2")
 		k3v3 := key.New("k3").String("v3")
 		ctx1 := context.WithValue(ctx, test1Type{}, 42)
-		span.AddEvent(ctx1, "one two three", k1v1)
+		sp.AddEvent(ctx1, "one two three", k1v1)
 		ctx2 := context.WithValue(ctx1, test2Type{}, "foo")
-		span.AddEvent(ctx2, "testing", k2v2, k3v3)
+		sp.AddEvent(ctx2, "testing", k2v2, k3v3)
 
 		got := obs.Events(exporter.ADD_EVENT)
 		for idx := range got {
@@ -54,16 +54,19 @@ func TestEvents(t *testing.T) {
 		if len(got) != 2 {
 			t.Errorf("Expected two events, got %d", len(got))
 		}
+		sdkSpan := sp.(*span)
 		want := []exporter.Event{
 			{
 				Type:       exporter.ADD_EVENT,
 				String:     "one two three",
 				Attributes: []core.KeyValue{k1v1},
+				Scope:      sdkSpan.ScopeID(),
 			},
 			{
 				Type:       exporter.ADD_EVENT,
 				String:     "testing",
 				Attributes: []core.KeyValue{k2v2, k3v3},
+				Scope:      sdkSpan.ScopeID(),
 			},
 		}
 		if diffEvents(t, got, want) {