From d917c9211ccaa506153fda244cfc07455a1a6f94 Mon Sep 17 00:00:00 2001
From: Nathan Bowler <nzb301@psu.edu>
Date: Wed, 6 Oct 2021 12:04:30 -0400
Subject: [PATCH] Encode SpanID and ParentSpanID as a 16 hex characters in
 zipkin propagator

Based on the openzipkin/b3-propagation specification, the SpanID and
ParentSpanID are to be encoded as 16 lower-hex characters.

https://github.com/jaegertracing/jaeger-client-go/pull/533 fixed this
for TraceID, and fixed the SpanID.String() method, but did not update
the Zipkin Propagator SpanID encoding.

This fix uses SpanID.String() to ensure proper encoding of the SpanID and
ParentSpandID within the Zipkin Propagator.

Signed-off-by: Nathan Bowler <nzb301@psu.edu>
---
 zipkin/propagation.go      |  4 ++--
 zipkin/propagation_test.go | 20 ++++++++++----------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/zipkin/propagation.go b/zipkin/propagation.go
index 722b0875..cd7d52d7 100644
--- a/zipkin/propagation.go
+++ b/zipkin/propagation.go
@@ -61,9 +61,9 @@ func (p Propagator) Inject(
 
 	textMapWriter.Set("x-b3-traceid", sc.TraceID().String())
 	if sc.ParentID() != 0 {
-		textMapWriter.Set("x-b3-parentspanid", strconv.FormatUint(uint64(sc.ParentID()), 16))
+		textMapWriter.Set("x-b3-parentspanid", sc.ParentID().String())
 	}
-	textMapWriter.Set("x-b3-spanid", strconv.FormatUint(uint64(sc.SpanID()), 16))
+	textMapWriter.Set("x-b3-spanid", sc.SpanID().String())
 	if sc.IsSampled() {
 		textMapWriter.Set("x-b3-sampled", "1")
 	} else {
diff --git a/zipkin/propagation_test.go b/zipkin/propagation_test.go
index d7c5c6f6..95771a7e 100644
--- a/zipkin/propagation_test.go
+++ b/zipkin/propagation_test.go
@@ -33,31 +33,31 @@ var (
 var (
 	rootSampledHeader = opentracing.TextMapCarrier{
 		"x-b3-traceid": "0000000000000001",
-		"x-b3-spanid":  "2",
+		"x-b3-spanid":  "0000000000000002",
 		"x-b3-sampled": "1",
 		"baggage-foo":  "bar",
 	}
 	nonRootSampledHeader = opentracing.TextMapCarrier{
 		"x-b3-traceid":      "0000000000000001",
-		"x-b3-spanid":       "2",
-		"x-b3-parentspanid": "1",
+		"x-b3-spanid":       "0000000000000002",
+		"x-b3-parentspanid": "0000000000000001",
 		"x-b3-sampled":      "1",
 	}
 	nonRootNonSampledHeader = opentracing.TextMapCarrier{
 		"x-b3-traceid":      "0000000000000001",
-		"x-b3-spanid":       "2",
-		"x-b3-parentspanid": "1",
+		"x-b3-spanid":       "0000000000000002",
+		"x-b3-parentspanid": "0000000000000001",
 		"x-b3-sampled":      "0",
 	}
 	rootSampledBooleanHeader = opentracing.TextMapCarrier{
 		"x-b3-traceid": "0000000000000001",
-		"x-b3-spanid":  "2",
+		"x-b3-spanid":  "0000000000000002",
 		"x-b3-sampled": "true",
 		"baggage-foo":  "bar",
 	}
 	nonRootSampledBooleanHeader = opentracing.TextMapCarrier{
 		"x-b3-traceid":      "0000000000000001",
-		"x-b3-spanid":       "2",
+		"x-b3-spanid":       "0000000000000002",
 		"x-b3-parentspanid": "1",
 		"x-b3-sampled":      "true",
 	}
@@ -69,12 +69,12 @@ var (
 	}
 	sampled128bitTraceID = opentracing.TextMapCarrier{
 		"x-b3-traceid": "463ac35c9f6413ad48485a3953bb6124",
-		"x-b3-spanid":  "2",
+		"x-b3-spanid":  "0000000000000002",
 		"x-b3-sampled": "1",
 	}
 	invalidTraceID = opentracing.TextMapCarrier{
 		"x-b3-traceid": "00000000000000000000000000000000",
-		"x-b3-spanid":  "2",
+		"x-b3-spanid":  "0000000000000002",
 		"x-b3-sampled": "1",
 	}
 )
@@ -157,7 +157,7 @@ func TestCustomBaggagePrefix(t *testing.T) {
 	assert.Nil(t, err)
 	m := opentracing.TextMapCarrier{
 		"x-b3-traceid": "0000000000000001",
-		"x-b3-spanid":  "2",
+		"x-b3-spanid":  "0000000000000002",
 		"x-b3-sampled": "1",
 		"emoji:)foo":   "bar",
 	}