Cleanup old tracing. By default generates single-line B3 only. TraceI…

…D can be queried.

client.go

@@ -232,7 +232,7 @@ func errDeadlineOrCancel(err error) bool {
 func doSpan(ctx context.Context, req *http.Request) string {
 	trace := newTraceFromCtx(ctx)
 	span := trace.span()
-	if trace.received || log.IsLevelEnabled(log.TraceLevel) {
+	if trace.received || isTraced {
 		span.setHeader(req.Header)
 	}
 	return span.string()

ctx.go

@@ -33,7 +33,7 @@ type Lambda struct {
 }
 
 func newLambda(w http.ResponseWriter, r *http.Request, vars map[string]string) *Lambda {
-	return &Lambda{w: w, r: r, trace: newTrace(r), vars: vars}
+	return &Lambda{w: w, r: r, trace: newTraceFromHeader(r), vars: vars}
 }
 
 // NewRequestCtx adds request related data to r.Context().
@@ -137,3 +137,9 @@ func (l *Lambda) ResponseHeaderAddAs(header, value string) {
 	h := l.w.Header()
 	h[header] = append(h[header], value)
 }
+
+// TraceID returns trace ID of Lambda context.
+// That trace ID is either received in request or generated when Lambda context is created.
+func (l *Lambda) TraceID() string {
+	return l.trace.traceID()
+}

trace.go

@@ -13,41 +13,48 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+var isTraced bool = true
+
+// SetTrace can enable/disable tracing in restful. By default tracing is enabled
+func SetTrace(b bool) {
+	isTraced = b
+}
+
 type trace struct {
 	parent   *traceParent
 	b3       *traceB3
 	received bool
 }
 
-// newTrace creates new trace object. Never returns nil.
-func newTrace(r *http.Request) *trace {
+// newTraceFromHeader creates new trace object. If no trace data, then create random. Never returns nil.
+func newTraceFromHeader(r *http.Request) *trace {
 	t := trace{parent: newTraceParent(r), b3: newTraceB3(r)}
 	t.received = t.valid()
 
-	if !t.received { // Create fake one. Saved to r (ctx.r), so that any client to be able to find it. Note: Logger may have created one already.
-		t.parent = newTraceParentFromFake(r)
-		if !t.valid() {
-			return newTraceRandom()
-		}
+	if !t.received {
+		return newTraceRandom()
 	}
 
 	return &t
 }
 
 func newTraceRandom() *trace {
-	if log.IsLevelEnabled(log.TraceLevel) {
-		traceID := randStr32()
-		return &trace{parent: newTraceParentWithID(traceID), b3: newTraceB3WithID(traceID, true)}
-	}
-	return &trace{b3: &traceB3{spanID: randStr16()}}
+	debug := log.IsLevelEnabled(log.TraceLevel)
+	traceID := randStr32()
+	return &trace{b3: newTraceB3WithID(traceID, debug)}
 }
 
 // newTraceFromCtx creates new trace object, preferably from context. Never returns nil.
 func newTraceFromCtx(ctx context.Context) *trace {
 	l := L(ctx)
-	if l == nil || l.trace == nil {
+	if l == nil {
 		return newTraceRandom()
 	}
+
+	if !l.trace.valid() {
+		l.trace = newTraceRandom() // Updates trace in ctx via l.trace pointer.
+	}
+
 	return l.trace
 }
 

trace_test.go

@@ -18,31 +18,19 @@ func TestRecvdParent(t *testing.T) {
 	assert := assert.New(t)
 	r, _ := http.NewRequest("POST", "", nil)
 	r.Header.Set("traceparent", "00-0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-01")
-	trace := newTrace(r)
+	trace := newTraceFromHeader(r)
 	assert.True(trace.received)
 	assert.Equal("00-0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-01", trace.string())
 	span := trace.span().string()
 	assert.Contains(span, "00-0af7651916cd43dd8448eb211c80319c-")
 	assert.Equal(55, len(span))
 }
 
-func TestFakeParent(t *testing.T) {
-	assert := assert.New(t)
-	r, _ := http.NewRequest("POST", "", nil)
-	r.Header.Set("x-fake-traceparent", "00-0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-01")
-	trace := newTrace(r)
-	assert.False(trace.received)
-	assert.Equal("00-0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-01", trace.string())
-	span := trace.span().string()
-	assert.Contains(span, "00-0af7651916cd43dd8448eb211c80319c-")
-	assert.Equal(55, len(span))
-}
-
 func TestRecvdBadParent(t *testing.T) {
 	assert := assert.New(t)
 	r, _ := http.NewRequest("POST", "", nil)
 	r.Header.Set("traceparent", "FF-0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-01")
-	trace := newTrace(r)
+	trace := newTraceFromHeader(r)
 	assert.False(trace.received)
 	assert.NotContains(trace.string(), "-0af7651916cd43dd8448eb211c80319c-")
 }
@@ -63,7 +51,7 @@ func TestB3SingleLine(t *testing.T) {
 	r, _ := http.NewRequest("POST", "", nil)
 	traceStr := "0af7651916cd43dd8448eb211c80319c-b9c7c989f97918e1-1-deadbeef87654321"
 	r.Header.Set("b3", traceStr)
-	trace := newTrace(r)
+	trace := newTraceFromHeader(r)
 	assert.True(trace.received)
 	assert.Contains(trace.string(), "0af7651916cd43dd8448eb211c80319c")
 	headers := http.Header{}
@@ -73,11 +61,10 @@ func TestB3SingleLine(t *testing.T) {
 
 func TestTracePropagation(t *testing.T) {
 	assert := assert.New(t)
-	log.SetLevel(log.TraceLevel) // That switches on trace generation and propagation
 
 	// Server
 	srvURL := ""
-	traceid := ""
+	traceID := ""
 	prevSpanID := ""
 	parents := make(map[string]bool)
 	depth := 0
@@ -87,17 +74,16 @@ func TestTracePropagation(t *testing.T) {
 		t := newTraceFromCtx(ctx)
 		assert.True(t.received)
 		if depth == 0 {
-			traceid = t.traceID()
+			traceID = t.traceID()
 			prevSpanID = t.spanID()
 			parents[t.string()] = true
 			t.b3.sampled = "1"
 			t.b3.requestID = "req"
 			t.b3.spanCtx = "ctx"
 		} else {
-			assert.Equal(traceid, t.parent.traceID())
+			assert.Equal(traceID, t.traceID())
+			assert.Equal(traceID, L(ctx).TraceID())
 			assert.NotContains(parents, t.string())
-			assert.Equal(t.parent.traceID(), t.b3.traceID)
-			assert.Equal(t.parent.spanID(), t.b3.spanID)
 			assert.Equal(prevSpanID, t.b3.parentSpanID)
 			assert.Equal("1", t.b3.sampled)
 			assert.Equal("req", t.b3.requestID)

traceb3.go

@@ -89,9 +89,9 @@ func newTraceB3(r *http.Request) *traceB3 {
 	return b3
 }
 
-func newTraceB3WithID(traceID string, trace bool) *traceB3 {
+func newTraceB3WithID(traceID string, debug bool) *traceB3 {
 	b3 := traceB3{traceID: traceID, singleLine: true}
-	if trace {
+	if debug {
 		b3.sampled = "d"
 	}
 	return &b3

traceparent.go

@@ -5,7 +5,6 @@
 package restful
 
 import (
-	"fmt"
 	"net/http"
 	"strings"
 )
@@ -15,9 +14,8 @@ See https://www.w3.org/TR/trace-context
 */
 
 const (
-	headerTraceParent     = "traceparent"
-	headerTraceState      = "tracestate"
-	headerFakeTraceParent = "x-fake-traceparent"
+	headerTraceParent = "traceparent"
+	headerTraceState  = "tracestate"
 )
 
 type traceParent struct {
@@ -29,14 +27,6 @@ func newTraceParent(r *http.Request) *traceParent { // May return nil.
 	return newTraceParentFromHeaderValue(r.Header.Get(headerTraceParent), r.Header.Get(headerTraceState))
 }
 
-func newTraceParentFromFake(r *http.Request) *traceParent {
-	return newTraceParentFromHeaderValue(r.Header.Get(headerFakeTraceParent), "") // Our server logger may have faked one already.
-}
-
-func newTraceParentWithID(traceID string) *traceParent {
-	return &traceParent{parent: []string{"00", traceID, fmt.Sprintf("%016x", 0) /*invalid, span resolves that*/, "00"}}
-}
-
 func newTraceParentFromHeaderValue(traceparent, tracestate string) *traceParent {
 	parent := strings.Split(traceparent, "-")
 	if len(parent) != 4 {