From b0cc392056b4290ccbea2f60a6c642738515d4a7 Mon Sep 17 00:00:00 2001
From: Daniel Dyla <dyladan@users.noreply.github.com>
Date: Fri, 17 Jan 2020 17:19:45 -0500
Subject: [PATCH 1/2] chore: simplify and speed up trace context parsing

---
 .../context/propagation/HttpTraceContext.ts   | 35 ++++---------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts b/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
index b003572f2b..d083ee1eac 100644
--- a/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
+++ b/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
@@ -14,15 +14,12 @@
  * limitations under the License.
  */
 
-import { SpanContext, HttpTextFormat, TraceFlags } from '@opentelemetry/types';
+import { HttpTextFormat, SpanContext, TraceFlags } from '@opentelemetry/types';
 import { TraceState } from '../../trace/TraceState';
 
 export const TRACE_PARENT_HEADER = 'traceparent';
 export const TRACE_STATE_HEADER = 'tracestate';
-const VALID_TRACE_PARENT_REGEX = /^[\da-f]{2}-[\da-f]{32}-[\da-f]{16}-[\da-f]{2}$/;
-const VALID_TRACEID_REGEX = /^[0-9a-f]{32}$/i;
-const VALID_SPANID_REGEX = /^[0-9a-f]{16}$/i;
-const INVALID_ID_REGEX = /^0+$/i;
+const VALID_TRACE_PARENT_REGEX = /^00-([\da-f]{32})-([\da-f]{16})-([\da-f]{2})$/;
 const VERSION = '00';
 
 /**
@@ -37,33 +34,15 @@ const VERSION = '00';
  */
 export function parseTraceParent(traceParent: string): SpanContext | null {
   const match = traceParent.match(VALID_TRACE_PARENT_REGEX);
-  if (!match) return null;
-  const parts = traceParent.split('-');
-  const [version, traceId, spanId, option] = parts;
-  // tslint:disable-next-line:ban Needed to parse hexadecimal.
-  const traceFlags = parseInt(option, 16);
-
   if (
-    !isValidVersion(version) ||
-    !isValidTraceId(traceId) ||
-    !isValidSpanId(spanId)
+    !match ||
+    match[1] === '00000000000000000000000000000000' ||
+    match[2] === '0000000000000000'
   ) {
     return null;
   }
 
-  return { traceId, spanId, traceFlags };
-}
-
-function isValidVersion(version: string): boolean {
-  return version === VERSION;
-}
-
-function isValidTraceId(traceId: string): boolean {
-  return VALID_TRACEID_REGEX.test(traceId) && !INVALID_ID_REGEX.test(traceId);
-}
-
-function isValidSpanId(spanId: string): boolean {
-  return VALID_SPANID_REGEX.test(spanId) && !INVALID_ID_REGEX.test(spanId);
+  return { traceId: match[1], spanId: match[2], traceFlags: parseInt(match[3], 16) };
 }
 
 /**
@@ -80,7 +59,7 @@ export class HttpTraceContext implements HttpTextFormat {
   ) {
     const traceParent = `${VERSION}-${spanContext.traceId}-${
       spanContext.spanId
-    }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
+      }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
 
     carrier[TRACE_PARENT_HEADER] = traceParent;
     if (spanContext.traceState) {

From 359eeaf03b0c8172f0a63494b6ffaf34654abc5e Mon Sep 17 00:00:00 2001
From: Daniel Dyla <dyladan@users.noreply.github.com>
Date: Fri, 17 Jan 2020 17:51:33 -0500
Subject: [PATCH 2/2] chore: lint

---
 .../src/context/propagation/HttpTraceContext.ts           | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts b/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
index d083ee1eac..9e42f991c2 100644
--- a/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
+++ b/packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts
@@ -42,7 +42,11 @@ export function parseTraceParent(traceParent: string): SpanContext | null {
     return null;
   }
 
-  return { traceId: match[1], spanId: match[2], traceFlags: parseInt(match[3], 16) };
+  return {
+    traceId: match[1],
+    spanId: match[2],
+    traceFlags: parseInt(match[3], 16),
+  };
 }
 
 /**
@@ -59,7 +63,7 @@ export class HttpTraceContext implements HttpTextFormat {
   ) {
     const traceParent = `${VERSION}-${spanContext.traceId}-${
       spanContext.spanId
-      }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
+    }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
 
     carrier[TRACE_PARENT_HEADER] = traceParent;
     if (spanContext.traceState) {