Trace sdk (#65)

* trace sdk initial commit.

* fix imports and comments.

* remove tracestate

* split trace.go

* add attribute over limit test.

* add comments and restructure span.go and tracer.go

* refactor MessageEvent

* defer unlock

* some more cleanup in span.go

* rename *MessageEvent* to *Event*

* cleanup comments in trace_test.go

* fix typos.

* return full string ID for traceID and spanID.

api/core/span_context.go

@@ -53,14 +53,13 @@ func (sc SpanContext) HasSpanID() bool {
 }
 
 func (sc SpanContext) SpanIDString() string {
-	p := fmt.Sprintf("%.16x", sc.SpanID)
-	return p[0:3] + ".." + p[13:16]
+	return fmt.Sprintf("%.16x", sc.SpanID)
 }
 
 func (sc SpanContext) TraceIDString() string {
 	p1 := fmt.Sprintf("%.16x", sc.TraceID.High)
 	p2 := fmt.Sprintf("%.16x", sc.TraceID.Low)
-	return p1[0:3] + ".." + p2[13:16]
+	return p1 + p2
 }
 
 func (sc SpanContext) IsSampled() bool {

api/core/span_context_test.go

@@ -88,11 +88,11 @@ func TestSpanIDString(t *testing.T) {
 		{
 			name: "fourtytwo",
 			sc:   SpanContext{SpanID: uint64(42)},
-			want: `000..02a`,
+			want: `000000000000002a`,
 		}, {
 			name: "empty",
 			sc:   SpanContext{},
-			want: `000..000`,
+			want: `0000000000000000`,
 		},
 	} {
 		t.Run(testcase.name, func(t *testing.T) {
@@ -119,11 +119,11 @@ func TestTraceIDString(t *testing.T) {
 					Low:  uint64(42),
 				},
 			},
-			want: `000..02a`,
+			want: `000000000000002a000000000000002a`,
 		}, {
 			name: "empty",
 			sc:   SpanContext{TraceID: TraceID{}},
-			want: `000..000`,
+			want: `00000000000000000000000000000000`,
 		},
 	} {
 		t.Run(testcase.name, func(t *testing.T) {