refactor(telemetry): OTel-format ids and explicit session id (#935)

Cleans up the local JSONL schema: `session_id` no longer leaks `vscode.env.sessionId`'s UUID+timestamp shape, and `event_id` / `trace_id` use OTel lowercase hex instead of UUIDv4.

- New `src/telemetry/ids.ts`: `newTraceId` (32 hex), `newSpanId` (16 hex), `newSessionId` (32 hex)
- `ServiceContainer` generates one session id and threads it to both sink filename and event payload
- Tests updated for the new id format

Follow-up to #934

Author: EhabY

src/core/container.ts

@@ -3,7 +3,8 @@ import * as vscode from "vscode";
 import { CoderApi } from "../api/coderApi";
 import { LoginCoordinator } from "../login/loginCoordinator";
 import { OAuthCallback } from "../oauth/oauthCallback";
-import { extractExtensionVersion } from "../telemetry/event";
+import { buildSession, extractExtensionVersion } from "../telemetry/event";
+import { newSessionId } from "../telemetry/ids";
 import { TelemetryService } from "../telemetry/service";
 import { LocalJsonlSink } from "../telemetry/sinks/localJsonlSink";
 import { SpeedtestPanelFactory } from "../webviews/speedtest/speedtestPanelFactory";
@@ -94,15 +95,21 @@ export class ServiceContainer implements vscode.Disposable {
 			context.extensionUri,
 			this.logger,
 		);
+
+		const sessionId = newSessionId();
 		const localJsonlSink = LocalJsonlSink.start(
 			{
 				baseDir: this.pathResolver.getTelemetryPath(),
-				sessionId: vscode.env.sessionId,
+				sessionId,
 			},
 			this.logger,
 		);
-		this.telemetryService = new TelemetryService(
+		const session = buildSession(
 			extractExtensionVersion(context.extension.packageJSON),
+			sessionId,
+		);
+		this.telemetryService = new TelemetryService(
+			session,
 			[localJsonlSink],
 			this.logger,
 		);

src/telemetry/event.ts

@@ -69,11 +69,14 @@ export interface TelemetrySink {
 }
 
 /** Build session attributes from the extension version and ambient host data. */
-export function buildSession(extensionVersion: string): SessionContext {
+export function buildSession(
+	extensionVersion: string,
+	sessionId: string,
+): SessionContext {
 	return {
 		extensionVersion,
 		machineId: vscode.env.machineId,
-		sessionId: vscode.env.sessionId,
+		sessionId,
 		osType: detectOsType(),
 		osVersion: os.release(),
 		hostArch: process.arch,

src/telemetry/ids.ts

@@ -0,0 +1,20 @@
+import { randomBytes } from "node:crypto";
+
+// OTel-format ids: lowercase hex, no separators. Keeps a future OTel
+// exporter a 1:1 mapping.
+
+/** OTel `trace_id`: 16 bytes / 32 hex. */
+export function newTraceId(): string {
+	return randomBytes(16).toString("hex");
+}
+
+/** OTel `span_id` (used as `event_id`): 8 bytes / 16 hex. */
+export function newSpanId(): string {
+	return randomBytes(8).toString("hex");
+}
+
+/** Our own session id (16 bytes / 32 hex). Avoids `vscode.env.sessionId`,
+ * which is a UUID concatenated with a timestamp. */
+export function newSessionId(): string {
+	return randomBytes(16).toString("hex");
+}

src/telemetry/service.ts

@@ -8,7 +8,6 @@ import {
 } from "../settings/telemetry";
 
 import {
-	buildSession,
 	buildErrorBlock,
 	type CallerMeasurements,
 	type CallerProperties,
@@ -17,6 +16,7 @@ import {
 	type TelemetryLevel,
 	type TelemetrySink,
 } from "./event";
+import { newSpanId, newTraceId } from "./ids";
 import { NOOP_SPAN, type Span } from "./span";
 
 const LEVEL_ORDER: Readonly<Record<TelemetryLevel, number>> = {
@@ -52,11 +52,11 @@ export class TelemetryService implements vscode.Disposable {
 	readonly #configWatcher: vscode.Disposable;
 
 	public constructor(
-		extensionVersion: string,
+		session: SessionContext,
 		private readonly sinks: readonly TelemetrySink[],
 		private readonly logger: Logger,
 	) {
-		this.#session = buildSession(extensionVersion);
+		this.#session = session;
 		this.#level = readLevel();
 		this.#configWatcher = watchConfigurationChanges(
 			[{ setting: TELEMETRY_LEVEL_SETTING, getValue: readLevel }],
@@ -86,7 +86,7 @@ export class TelemetryService implements vscode.Disposable {
 		if (this.#level === "off") {
 			return;
 		}
-		this.#safeEmit(crypto.randomUUID(), eventName, properties, measurements);
+		this.#safeEmit(newSpanId(), eventName, properties, measurements);
 	}
 
 	public logError(
@@ -98,7 +98,7 @@ export class TelemetryService implements vscode.Disposable {
 		if (this.#level === "off") {
 			return;
 		}
-		this.#safeEmit(crypto.randomUUID(), eventName, properties, measurements, {
+		this.#safeEmit(newSpanId(), eventName, properties, measurements, {
 			error,
 		});
 	}
@@ -118,7 +118,7 @@ export class TelemetryService implements vscode.Disposable {
 			return fn(NOOP_SPAN);
 		}
 		return this.#startSpan(eventName, fn, properties, measurements, {
-			traceId: crypto.randomUUID(),
+			traceId: newTraceId(),
 			traceLevel: this.#level,
 		});
 	}
@@ -140,7 +140,7 @@ export class TelemetryService implements vscode.Disposable {
 		measurements: Record<string, number>,
 		spanOpts: SpanOptions,
 	): Promise<T> {
-		const eventId = crypto.randomUUID();
+		const eventId = newSpanId();
 		const { traceId, traceLevel } = spanOpts;
 		const span: Span = {
 			traceId,

test/unit/core/commandManager.test.ts

@@ -8,6 +8,7 @@ import {
 	CommandManager,
 	type CoderCommandId,
 } from "@/core/commandManager";
+import { buildSession } from "@/telemetry/event";
 import { TelemetryService } from "@/telemetry/service";
 
 import { TestSink } from "../../mocks/telemetry";
@@ -26,7 +27,7 @@ function makeHarness(): Harness {
 	config.set("coder.telemetry.level", "local");
 	const sink = new TestSink();
 	const telemetry = new TelemetryService(
-		"1.2.3-test",
+		buildSession("1.2.3-test", "test-session"),
 		[sink],
 		createMockLogger(),
 	);

test/unit/telemetry/event.test.ts

@@ -7,13 +7,13 @@ import {
 } from "@/telemetry/event";
 
 describe("buildSession", () => {
-	it("populates session-stable fields from the version, vscode env, and host", () => {
-		const session = buildSession("1.2.3-test");
+	it("populates session-stable fields from the version, sessionId, vscode env, and host", () => {
+		const session = buildSession("1.2.3-test", "session-abc");
 
 		expect(session).toMatchObject({
 			extensionVersion: "1.2.3-test",
 			machineId: "test-machine-id",
-			sessionId: "test-session-id",
+			sessionId: "session-abc",
 			platformName: "Visual Studio Code",
 			platformVersion: "1.106.0-test",
 			hostArch: process.arch,

test/unit/telemetry/service.test.ts

@@ -1,5 +1,6 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
+import { buildSession, type TelemetrySink } from "@/telemetry/event";
 import { TelemetryService } from "@/telemetry/service";
 
 import { TestSink } from "../../mocks/telemetry";
@@ -8,9 +9,10 @@ import {
 	MockConfigurationProvider,
 } from "../../mocks/testHelpers";
 
-import type { TelemetrySink } from "@/telemetry/event";
-
 const TEST_VERSION = "1.2.3-test";
+const TEST_SESSION_ID = "test-session";
+
+const testSession = () => buildSession(TEST_VERSION, TEST_SESSION_ID);
 
 interface Harness {
 	service: TelemetryService;
@@ -23,7 +25,7 @@ function makeHarness(level: "off" | "local" = "local"): Harness {
 	config.set("coder.telemetry.level", level);
 	const sink = new TestSink();
 	const service = new TelemetryService(
-		TEST_VERSION,
+		testSession(),
 		[sink],
 		createMockLogger(),
 	);
@@ -32,7 +34,7 @@ function makeHarness(level: "off" | "local" = "local"): Harness {
 
 function makeService(sinks: TelemetrySink[]): TelemetryService {
 	new MockConfigurationProvider().set("coder.telemetry.level", "local");
-	return new TelemetryService(TEST_VERSION, sinks, createMockLogger());
+	return new TelemetryService(testSession(), sinks, createMockLogger());
 }
 
 describe("TelemetryService", () => {
@@ -57,13 +59,11 @@ describe("TelemetryService", () => {
 				context: {
 					extensionVersion: "1.2.3-test",
 					machineId: "test-machine-id",
-					sessionId: "test-session-id",
+					sessionId: TEST_SESSION_ID,
 					deploymentUrl: "",
 				},
 			});
-			expect(event.eventId).toMatch(
-				/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/,
-			);
+			expect(event.eventId).toMatch(/^[0-9a-f]{16}$/);
 			expect(event.timestamp).toMatch(/^\d{4}-\d{2}-\d{2}T/);
 		});