From 674ba90000acf9854fe7ba5e07c3971171bf417d Mon Sep 17 00:00:00 2001
From: Sandeep Somavarapu <sasomava@microsoft.com>
Date: Wed, 15 Mar 2023 19:24:00 +0100
Subject: [PATCH] #172336 Improve logging in web

---
 src/vs/platform/log/common/fileLog.ts         | 43 +++++++++++--------
 .../api/browser/mainThreadLogService.ts       |  8 ++++
 .../workbench/api/common/extHost.protocol.ts  |  1 +
 .../api/common/extHostLoggerService.ts        |  4 ++
 4 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/src/vs/platform/log/common/fileLog.ts b/src/vs/platform/log/common/fileLog.ts
index 60ad7b2f10c97..05d6579338d15 100644
--- a/src/vs/platform/log/common/fileLog.ts
+++ b/src/vs/platform/log/common/fileLog.ts
@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { Queue } from 'vs/base/common/async';
+import { ThrottledDelayer } from 'vs/base/common/async';
 import { VSBuffer } from 'vs/base/common/buffer';
 import { basename, dirname, joinPath } from 'vs/base/common/resources';
 import { URI } from 'vs/base/common/uri';
@@ -16,8 +16,9 @@ const MAX_FILE_SIZE = 5 * ByteSize.MB;
 class FileLogger extends AbstractMessageLogger implements ILogger {
 
 	private readonly initializePromise: Promise<void>;
-	private readonly queue: Queue<void>;
+	private readonly flushDelayer: ThrottledDelayer<void>;
 	private backupIndex: number = 1;
+	private buffer: string = '';
 
 	constructor(
 		private readonly resource: URI,
@@ -27,11 +28,25 @@ class FileLogger extends AbstractMessageLogger implements ILogger {
 	) {
 		super();
 		this.setLevel(level);
-		this.queue = this._register(new Queue<void>());
+		this.flushDelayer = new ThrottledDelayer<void>(100 /* buffer saves over a short time */);
 		this.initializePromise = this.initialize();
 	}
 
-	override flush(): void {
+	override async flush(): Promise<void> {
+		if (!this.buffer) {
+			return;
+		}
+		await this.initializePromise;
+		let content = await this.loadContent();
+		if (content.length > MAX_FILE_SIZE) {
+			await this.fileService.writeFile(this.getBackupResource(), VSBuffer.fromString(content));
+			content = '';
+		}
+		if (this.buffer) {
+			content += this.buffer;
+			this.buffer = '';
+			await this.fileService.writeFile(this.resource, VSBuffer.fromString(content));
+		}
 	}
 
 	private async initialize(): Promise<void> {
@@ -45,20 +60,12 @@ class FileLogger extends AbstractMessageLogger implements ILogger {
 	}
 
 	protected log(level: LogLevel, message: string): void {
-		this.queue.queue(async () => {
-			await this.initializePromise;
-			let content = await this.loadContent();
-			if (content.length > MAX_FILE_SIZE) {
-				await this.fileService.writeFile(this.getBackupResource(), VSBuffer.fromString(content));
-				content = '';
-			}
-			if (this.donotUseFormatters) {
-				content += message;
-			} else {
-				content += `${this.getCurrentTimestamp()} [${this.stringifyLogLevel(level)}] ${message}\n`;
-			}
-			await this.fileService.writeFile(this.resource, VSBuffer.fromString(content));
-		});
+		if (this.donotUseFormatters) {
+			this.buffer += message;
+		} else {
+			this.buffer += `${this.getCurrentTimestamp()} [${this.stringifyLogLevel(level)}] ${message}\n`;
+		}
+		this.flushDelayer.trigger(() => this.flush());
 	}
 
 	private getCurrentTimestamp(): string {
diff --git a/src/vs/workbench/api/browser/mainThreadLogService.ts b/src/vs/workbench/api/browser/mainThreadLogService.ts
index d4e83b4a14ac3..da8ac21f4fb4b 100644
--- a/src/vs/workbench/api/browser/mainThreadLogService.ts
+++ b/src/vs/workbench/api/browser/mainThreadLogService.ts
@@ -60,6 +60,14 @@ export class MainThreadLoggerService implements MainThreadLoggerShape {
 		this.loggerService.setVisibility(URI.revive(resource), visible);
 	}
 
+	$flush(file: UriComponents): void {
+		const logger = this.loggerService.getLogger(URI.revive(file));
+		if (!logger) {
+			throw new Error('Create the logger before flushing');
+		}
+		logger.flush();
+	}
+
 	dispose(): void {
 		this.disposables.dispose();
 	}
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index a1a33c11b0412..e640b255e0ed7 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -2055,6 +2055,7 @@ export interface ExtHostLogLevelServiceShape {
 
 export interface MainThreadLoggerShape {
 	$log(file: UriComponents, messages: [LogLevel, string][]): void;
+	$flush(file: UriComponents): void;
 	$createLogger(file: UriComponents, options?: ILoggerOptions): Promise<void>;
 	$registerLogger(logger: UriDto<ILoggerResource>): Promise<void>;
 	$deregisterLogger(resource: UriComponents): Promise<void>;
diff --git a/src/vs/workbench/api/common/extHostLoggerService.ts b/src/vs/workbench/api/common/extHostLoggerService.ts
index 8a9c7dbb072c9..1d7b4288378c6 100644
--- a/src/vs/workbench/api/common/extHostLoggerService.ts
+++ b/src/vs/workbench/api/common/extHostLoggerService.ts
@@ -73,4 +73,8 @@ class Logger extends AbstractMessageLogger {
 	private doLog(messages: [LogLevel, string][]) {
 		this.proxy.$log(this.file, messages);
 	}
+
+	override flush(): void {
+		this.proxy.$flush(this.file);
+	}
 }