Replace OpenTelemetry with custom tracing.

packages/next/telemetry/trace/index.ts

@@ -0,0 +1,65 @@
+import { randomBytes } from 'crypto'
+import reportToConsole from './to-console'
+import reportToLocalHost from './to-localhost'
+import reportToTelemetry from './to-telemetry'
+
+let idCounter = 0
+const idUniqToProcess = randomBytes(16).toString('base64').slice(0, 22)
+const getId = () => `${idUniqToProcess}:${idCounter++}`
+
+const noop = (
+  _spanName: string,
+  _duration: number,
+  _id: string | null,
+  _parentId: string | null,
+  _attrs: Object
+) => {}
+
+enum TARGET {
+  CONSOLE = 'CONSOLE',
+  LOCALHOST = 'LOCALHOST',
+  TELEMETRY = 'TELEMETRY',
+}
+
+const target =
+  process.env.TRACE_TARGET && process.env.TRACE_TARGET in TARGET
+    ? TARGET[process.env.TRACE_TARGET as TARGET]
+    : TARGET.TELEMETRY
+const traceLevel = process.env.TRACE_LEVEL
+  ? Number.parseInt(process.env.TRACE_LEVEL)
+  : 1
+
+let report = noop
+if (target === TARGET.CONSOLE) {
+  report = reportToConsole
+} else if (target === TARGET.LOCALHOST) {
+  report = reportToLocalHost
+} else {
+  report = reportToTelemetry
+}
+
+// This function reports durations in microseconds. This gives 1000x
+// the precision of something like Date.now(), which reports in
+// milliseconds.  Additionally, ~285 years can be safely represented
+// as microseconds as a float64 in both JSON and JavaScript.
+const trace = (spanName: string, parentId: string | null, attrs: Object) => {
+  const endSpan = () => {
+    const id = getId()
+    const end: bigint = process.hrtime.bigint()
+    const duration = end - start
+    if (duration > Number.MAX_SAFE_INTEGER) {
+      throw new Error(`Duration is too long to express as float64: ${duration}`)
+    }
+    report(spanName, Number(duration), id, parentId, attrs)
+  }
+
+  const start: bigint = process.hrtime.bigint()
+  return endSpan
+}
+
+module.exports = {
+  TARGET,
+  primary: traceLevel >= 1 ? trace : noop,
+  secondary: traceLevel >= 2 ? trace : noop,
+  sensitive: traceLevel >= 3 ? trace : noop,
+}

packages/next/telemetry/trace/to-console.ts

@@ -0,0 +1,9 @@
+const reportToConsole = (
+  _spanName: string,
+  _duration: number,
+  _id: string | null,
+  _parentId: string | null,
+  _attrs: Object
+) => {}
+
+export default reportToConsole

packages/next/telemetry/trace/to-localhost.ts

@@ -0,0 +1,9 @@
+const reportToLocalHost = (
+  _spanName: string,
+  _duration: number,
+  _id: string | null,
+  _parentId: string | null,
+  _attrs: Object
+) => {}
+
+export default reportToLocalHost

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

@@ -0,0 +1,9 @@
+const reportToTelemetry = (
+  _spanName: string,
+  _duration: number,
+  _id: string | null,
+  _parentId: string | null,
+  _attrs: Object
+) => {}
+
+export default reportToTelemetry