feat: enable traceparent header for cloudevents (#336)

Fixes: GoogleCloudPlatform#197

`traceparent` is the more modern header that includes information that `X-Cloud-Trace-Context` references.

Author: grant

src/cloudevents.ts

@@ -68,5 +68,10 @@ export function getBinaryCloudEventContext(
       context[attributeName] = req.header(name);
     }
   }
+
+  // Populate the traceparent header.
+  if (req.header('traceparent')) {
+    context.traceparent = req.header('traceparent');
+  }
   return context;
 }

src/functions.ts

@@ -126,6 +126,11 @@ export interface CloudEventsContext {
     | boolean
     | null
     | unknown;
+  /**
+   * The traceparent string, containing a trace version, trace ID, span ID, and trace options.
+   * @see https://github.com/cloudevents/spec/blob/master/extensions/distributed-tracing.md
+   */
+  traceparent?: string;
 }
 
 export type Context = CloudFunctionsContext | CloudEventsContext;

test/integration/cloudevent.ts

@@ -25,6 +25,7 @@ const TEST_CLOUD_EVENT = {
   subject: 'test-subject',
   id: 'test-1234-1234',
   time: '2020-05-13T01:23:45Z',
+  traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
   datacontenttype: 'application/json',
   data: {
     some: 'payload',
@@ -52,6 +53,17 @@ describe('CloudEvent Function', () => {
       body: TEST_CLOUD_EVENT,
       expectedCloudEvent: TEST_CLOUD_EVENT,
     },
+    {
+      name: 'CloudEvents v1.0 structured content request',
+      headers: {
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
+      },
+      body: TEST_CLOUD_EVENT,
+      expectedCloudEvent: {
+        ...TEST_CLOUD_EVENT,
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
+      },
+    },
     {
       name: 'CloudEvents v1.0 binary content request',
       headers: {
@@ -63,6 +75,7 @@ describe('CloudEvent Function', () => {
         'ce-id': TEST_CLOUD_EVENT.id,
         'ce-time': TEST_CLOUD_EVENT.time,
         'ce-datacontenttype': TEST_CLOUD_EVENT.datacontenttype,
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
       },
       body: TEST_CLOUD_EVENT.data,
       expectedCloudEvent: TEST_CLOUD_EVENT,

test/integration/legacy_event.ts

@@ -24,6 +24,7 @@ const TEST_CLOUD_EVENT = {
   subject: 'test-subject',
   id: 'test-1234-1234',
   time: '2020-05-13T01:23:45Z',
+  traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
   datacontenttype: 'application/json',
   data: {
     some: 'payload',
@@ -111,6 +112,7 @@ describe('Event Function', () => {
         specversion: '1.0',
         subject: 'test-subject',
         time: '2020-05-13T01:23:45Z',
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
         type: 'com.google.cloud.storage',
       },
     },
@@ -125,6 +127,7 @@ describe('Event Function', () => {
         'ce-id': TEST_CLOUD_EVENT.id,
         'ce-time': TEST_CLOUD_EVENT.time,
         'ce-datacontenttype': TEST_CLOUD_EVENT.datacontenttype,
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
       },
       body: TEST_CLOUD_EVENT.data,
       expectedData: TEST_CLOUD_EVENT.data,
@@ -136,6 +139,7 @@ describe('Event Function', () => {
         specversion: '1.0',
         subject: 'test-subject',
         time: '2020-05-13T01:23:45Z',
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
         type: 'com.google.cloud.storage',
       },
     },

test/middleware/background_event_to_cloudevent.ts

@@ -148,6 +148,7 @@ describe('backgroundEventToCloudEventMiddleware', () => {
         subject: 'test-subject',
         id: 'test-1234-1234',
         time: '2020-05-13T01:23:45Z',
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
         datacontenttype: 'application/json',
         data: {
           some: 'payload',
@@ -161,6 +162,7 @@ describe('backgroundEventToCloudEventMiddleware', () => {
         subject: 'test-subject',
         id: 'test-1234-1234',
         time: '2020-05-13T01:23:45Z',
+        traceparent: '00-65088630f09e0a5359677a7429456db7-97f23477fb2bf5ec-01',
         datacontenttype: 'application/json',
         data: {
           some: 'payload',