Add support for Jaeger trace target (#28129)

Adds support for Jaeger next to Zipkin as a trace target.

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes

packages/next/telemetry/trace/report/index.ts

@@ -1,6 +1,7 @@
 import { TARGET, SpanId } from '../shared'
 import reportToConsole from './to-console'
 import reportToZipkin from './to-zipkin'
+import reportToJaeger from './to-jaeger'
 import reportToTelemetry from './to-telemetry'
 
 type Reporter = (
@@ -28,6 +29,8 @@ if (target === TARGET.CONSOLE) {
   report = reportToConsole
 } else if (target === TARGET.ZIPKIN) {
   report = reportToZipkin
+} else if (target === TARGET.JAEGER) {
+  report = reportToJaeger
 } else {
   report = reportToTelemetry
 }

packages/next/telemetry/trace/report/to-jaeger.ts

@@ -0,0 +1,90 @@
+import retry from 'next/dist/compiled/async-retry'
+import { randomBytes } from 'crypto'
+import fetch from 'node-fetch'
+import * as Log from '../../../build/output/log'
+
+let traceId = process.env.TRACE_ID
+let batch: ReturnType<typeof batcher> | undefined
+
+const localEndpoint = {
+  serviceName: 'nextjs',
+  ipv4: '127.0.0.1',
+  port: 9411,
+}
+// Jaeger supports Zipkin's reporting API
+const zipkinUrl = `http://${localEndpoint.ipv4}:${localEndpoint.port}`
+const jaegerWebUiUrl = `http://${localEndpoint.ipv4}:16686`
+const zipkinAPI = `${zipkinUrl}/api/v2/spans`
+
+type Event = {
+  traceId: string
+  parentId?: string
+  name: string
+  id: string
+  timestamp: number
+  duration: number
+  localEndpoint: typeof localEndpoint
+  tags?: Object
+}
+
+// Batch events as zipkin allows for multiple events to be sent in one go
+function batcher(reportEvents: (evts: Event[]) => void) {
+  const events: Event[] = []
+  let timeout: ReturnType<typeof setTimeout> | undefined
+  return (event: Event) => {
+    events.push(event)
+    // setTimeout is used instead of setInterval to ensure events sending does not block exiting the program
+    if (!timeout) {
+      timeout = setTimeout(() => {
+        reportEvents(events.slice())
+        events.length = 0
+        timeout = undefined
+      }, 1500)
+    }
+  }
+}
+
+const reportToLocalHost = (
+  name: string,
+  duration: number,
+  timestamp: number,
+  id: string,
+  parentId?: string,
+  attrs?: Object
+) => {
+  if (!traceId) {
+    traceId = process.env.TRACE_ID = randomBytes(8).toString('hex')
+    Log.info(
+      `Jaeger trace will be available on ${jaegerWebUiUrl}/trace/${traceId}`
+    )
+  }
+
+  if (!batch) {
+    batch = batcher((events) => {
+      // Ensure ECONNRESET error is retried 3 times before erroring out
+      retry(
+        () =>
+          // Send events to zipkin
+          fetch(zipkinAPI, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify(events),
+          }),
+        { minTimeout: 500, retries: 3, factor: 1 }
+      ).catch(console.log)
+    })
+  }
+
+  batch({
+    traceId,
+    parentId,
+    name,
+    id,
+    timestamp,
+    duration,
+    localEndpoint,
+    tags: attrs,
+  })
+}
+
+export default reportToLocalHost

packages/next/telemetry/trace/shared.ts

@@ -3,6 +3,7 @@
 export enum TARGET {
   CONSOLE = 'CONSOLE',
   ZIPKIN = 'ZIPKIN',
+  JAEGER = 'JAEGER',
   TELEMETRY = 'TELEMETRY',
 }