extension/src: use enum for telemetry key

- Move activationLatency function from goMain.ts to goTelemetry.ts.
- Replace add() input parameter type of string with enum type
TelemetryKey.

Follow variable naming conventions:
- enum declaration use UpperCamelCase
- enum value use CONSTANT_CASE
https://google.github.io/styleguide/tsguide.html#naming-rules-by-identifier-type

Bucketing variable name follow prometheus histogram naming:
L: less than, LE: less than or equal to
G: greater than, GE: greater than or equal to

For #3697

Change-Id: I1472bc58752f08b6f0feb1316284cfe10b214f4b
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/661056
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Hongxiang Jiang <hxjiang@golang.org>
Reviewed-by: Madeline Kalil <mkalil@google.com>
Reviewed-by: Peter Weinberger <pjw@google.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>

Author: h9jiang

extension/src/goInstallTools.ts

@@ -39,7 +39,7 @@ import {
 import util = require('util');
 import vscode = require('vscode');
 import { RestartReason } from './language/goLanguageServer';
-import { telemetryReporter } from './goTelemetry';
+import { TelemetryKey, telemetryReporter } from './goTelemetry';
 import { allToolsInformation } from './goToolsInformation';
 
 const STATUS_BAR_ITEM_NAME = 'Go Tools';
@@ -937,7 +937,7 @@ export async function maybeInstallVSCGO(
 	if (extensionMode === vscode.ExtensionMode.Production && executableFileExists(progPath)) {
 		return progPath; // reuse existing executable.
 	}
-	telemetryReporter.add('vscgo_install', 1);
+	telemetryReporter.add(TelemetryKey.VSCGO_INSTALL, 1);
 	const mkdir = util.promisify(fs.mkdir);
 	await mkdir(path.dirname(progPath), { recursive: true });
 	const execFile = util.promisify(cp.execFile);
@@ -965,7 +965,7 @@ export async function maybeInstallVSCGO(
 		await execFile(goBinary, args, { cwd, env });
 		return progPath;
 	} catch (e) {
-		telemetryReporter.add('vscgo_install_fail', 1);
+		telemetryReporter.add(TelemetryKey.VSCGO_INSTALL_FAIL, 1);
 		return Promise.reject(`failed to install vscgo - ${e}`);
 	}
 }

extension/src/goMain.ts

@@ -73,7 +73,7 @@ import { GoExtensionContext } from './context';
 import * as commands from './commands';
 import { toggleVulncheckCommandFactory } from './goVulncheck';
 import { GoTaskProvider } from './goTaskProvider';
-import { setTelemetryEnvVars, telemetryReporter } from './goTelemetry';
+import { setTelemetryEnvVars, activationLatency, telemetryReporter } from './goTelemetry';
 import { experiments } from './experimental';
 import { allToolsInformation } from './goToolsInformation';
 
@@ -240,22 +240,6 @@ export async function activate(ctx: vscode.ExtensionContext): Promise<ExtensionA
 	return extensionAPI;
 }
 
-function activationLatency(duration: number): string {
-	// TODO: generalize and move to goTelemetry.ts
-	let bucket = '>=5s';
-
-	if (duration < 100) {
-		bucket = '<100ms';
-	} else if (duration < 500) {
-		bucket = '<500ms';
-	} else if (duration < 1000) {
-		bucket = '<1s';
-	} else if (duration < 5000) {
-		bucket = '<5s';
-	}
-	return 'activation_latency:' + bucket;
-}
-
 export function deactivate() {
 	return Promise.all([
 		goCtx.languageClient?.stop(),

extension/src/goTelemetry.ts

@@ -36,6 +36,41 @@ export function recordTelemetryStartTime(storage: vscode.Memento, date: Date) {
 	storage.update(TELEMETRY_START_TIME_KEY, date.toJSON());
 }
 
+/**
+ * TelemetryKey represents the different types of telemetry events.
+ */
+export enum TelemetryKey {
+	// Indicates the installation of vscgo binary.
+	VSCGO_INSTALL = 'vscgo_install',
+	VSCGO_INSTALL_FAIL = 'vscgo_install_fail',
+
+	// Indicates the activation latency.
+	ACTIVATION_LATENCY_L_100MS = 'activation_latency:<100ms',
+	ACTIVATION_LATENCY_L_500MS = 'activation_latency:<500ms',
+	ACTIVATION_LATENCY_L_1000MS = 'activation_latency:<1000ms',
+	ACTIVATION_LATENCY_L_5000MS = 'activation_latency:<5000ms',
+	ACTIVATION_LATENCY_GE_5S = 'activation_latency:>=5s'
+}
+
+/**
+ * Categorizes a duration into a specific latency bucket.
+ *
+ * @param duration The duration in milliseconds.
+ * @returns The TelemetryKey representing the latency bucket.
+ */
+export function activationLatency(duration: number): TelemetryKey {
+	if (duration < 100) {
+		return TelemetryKey.ACTIVATION_LATENCY_L_100MS;
+	} else if (duration < 500) {
+		return TelemetryKey.ACTIVATION_LATENCY_L_500MS;
+	} else if (duration < 1000) {
+		return TelemetryKey.ACTIVATION_LATENCY_L_1000MS;
+	} else if (duration < 5000) {
+		return TelemetryKey.ACTIVATION_LATENCY_L_5000MS;
+	}
+	return TelemetryKey.ACTIVATION_LATENCY_GE_5S;
+}
+
 function readTelemetryStartTime(storage: vscode.Memento): Date | null {
 	const value = storage.get<string | number | Date>(TELEMETRY_START_TIME_KEY);
 	if (!value) {
@@ -109,12 +144,12 @@ export class TelemetryReporter implements vscode.Disposable {
 	/**
 	 * Adds a numeric value to a counter associated with the given key.
 	 */
-	public add(key: string, value: number) {
+	public add(key: TelemetryKey, value: number) {
 		if (value <= 0) {
 			return;
 		}
-		key = key.replace(/[\s\n]/g, '_');
-		this._counters[key] = (this._counters[key] || 0) + value;
+		const sanitized = key.replace(/[\s\n]/g, '_');
+		this._counters[sanitized] = (this._counters[sanitized] || 0) + value;
 	}
 
 	/**
@@ -197,7 +232,7 @@ export const telemetryReporter = new TelemetryReporter();
 
 // TODO(hyangah): consolidate the list of all the telemetries and bucketting functions.
 
-export function addTelemetryEvent(name: string, count: number) {
+export function addTelemetryEvent(name: TelemetryKey, count: number) {
 	telemetryReporter.add(name, count);
 }
 

extension/src/goTest.ts

@@ -25,7 +25,6 @@ import {
 	SuiteToTestMap,
 	getTestFunctions
 } from './testUtils';
-import type { GoRunTestCodeLensProvider } from './goRunTestCodelens';
 
 // lastTestConfig holds a reference to the last executed TestConfig which allows
 // the last test to be easily re-executed.

extension/test/gopls/telemetry.test.ts

@@ -9,6 +9,7 @@ import { describe, it } from 'mocha';
 import {
 	GOPLS_MAYBE_PROMPT_FOR_TELEMETRY,
 	TELEMETRY_START_TIME_KEY,
+	TelemetryKey,
 	TelemetryReporter,
 	TelemetryService,
 	recordTelemetryStartTime
@@ -189,8 +190,8 @@ describe('# telemetry reporter using vscgo', async function () {
 	});
 
 	it('add succeeds before telemetryReporter.setTool runs', () => {
-		sut.add('hello', 1);
-		sut.add('world', 2);
+		sut.add(TelemetryKey.VSCGO_INSTALL, 1);
+		sut.add(TelemetryKey.VSCGO_INSTALL_FAIL, 2);
 	});
 
 	it('flush is noop before setTool', async () => {
@@ -202,13 +203,13 @@ describe('# telemetry reporter using vscgo', async function () {
 		sut.setTool(vscgo);
 		await sut.flush();
 		const readAll = fs.readFileSync(counterfile).toString();
-		assert(readAll.includes('hello 1\n') && readAll.includes('world 2\n'), readAll);
+		assert(readAll.includes('vscgo_install 1\n') && readAll.includes('vscgo_install_fail 2\n'), readAll);
 	});
 
 	it('dispose triggers flush', async () => {
-		sut.add('bye', 3);
+		sut.add(TelemetryKey.ACTIVATION_LATENCY_GE_5S, 3);
 		await sut.dispose();
 		const readAll = fs.readFileSync(counterfile).toString();
-		assert(readAll.includes('bye 3\n'), readAll);
+		assert(readAll.includes('activation_latency:>=5s 3\n'), readAll);
 	});
 });