AsyncLocalStorage experiment (nonfunctional)

#296

src/Command.ts

@@ -1,6 +1,6 @@
 import { RESTPostAPIApplicationCommandsJSONBody } from "discord-api-types/v10";
 import { AutocompleteInteraction, ChatInputCommandInteraction } from "discord.js";
-import { Logger } from "./logger";
+import { Logger, asyncLocalStorage } from "./logger";
 import { Metrics } from "./metrics";
 import { serialiseInteraction } from "./utils";
 
@@ -34,28 +34,30 @@ export abstract class Command {
 	 * @param interaction
 	 */
 	async run(interaction: ChatInputCommandInteraction): Promise<void> {
-		try {
-			this.logger.verbose(
-				serialiseInteraction(interaction, { event: "attempt", ping: interaction.client.ws.ping })
-			);
-			const latency = await this.execute(interaction);
-			this.logger.verbose(serialiseInteraction(interaction, { event: "success", latency }));
-			this.metrics.writeCommand(interaction, latency);
-		} catch (error) {
-			this.metrics.writeCommand(interaction, -1);
-			this.logger.error(serialiseInteraction(interaction), error);
-			let method;
-			if (interaction.replied) {
-				method = "followUp" as const;
-			} else if (interaction.deferred) {
-				method = "editReply" as const;
-			} else {
-				method = "reply" as const;
+		await asyncLocalStorage.run(interaction, async () => {
+			try {
+				this.logger.verbose(
+					serialiseInteraction(interaction, { event: "attempt", ping: interaction.client.ws.ping })
+				);
+				const latency = await this.execute(interaction);
+				this.logger.verbose(serialiseInteraction(interaction, { event: "success", latency }));
+				this.metrics.writeCommand(interaction, latency);
+			} catch (error) {
+				this.metrics.writeCommand(interaction, -1);
+				this.logger.error(serialiseInteraction(interaction), error);
+				let method;
+				if (interaction.replied) {
+					method = "followUp" as const;
+				} else if (interaction.deferred) {
+					method = "editReply" as const;
+				} else {
+					method = "reply" as const;
+				}
+				await interaction[method]("Something went wrong. Please try again later.").catch(e =>
+					this.logger.error(serialiseInteraction(interaction), e)
+				);
 			}
-			await interaction[method]("Something went wrong. Please try again later.").catch(e =>
-				this.logger.error(serialiseInteraction(interaction), e)
-			);
-		}
+		});
 	}
 }
 

src/logger.ts

@@ -1,27 +1,53 @@
+import { AsyncLocalStorage } from "async_hooks";
 import debug, { Debug } from "debug";
-import { escapeMarkdown, WebhookClient } from "discord.js";
+import { AutocompleteInteraction, CommandInteraction, escapeMarkdown, Message, WebhookClient } from "discord.js";
 import util from "util";
+import { serialiseInteraction } from "./utils";
 
 const global = debug("bot");
 
 const webhook = process.env.BOT_LOGGER_WEBHOOK ? new WebhookClient({ url: process.env.BOT_LOGGER_WEBHOOK }) : null;
 
+export const asyncLocalStorage = new AsyncLocalStorage<CommandInteraction | AutocompleteInteraction | Message>();
+
+function contextLog(log: debug.Debugger): Debug["log"] {
+	return function (...args: Parameters<debug.Debugger>) {
+		const context = asyncLocalStorage.getStore();
+		if (context) {
+			if ("commandId" in context) {
+				log(serialiseInteraction(context), ...args);
+			} else {
+				log(
+					JSON.stringify({
+						channel: context.channelId,
+						message: context.id,
+						guild: context.guildId,
+						author: context.author.id
+					}),
+					...args
+				);
+			}
+		} else {
+			log(...args);
+		}
+	};
+}
 function withWebhook(log: debug.Debugger): Debug["log"] {
 	if (webhook) {
 		return function (...args: Parameters<debug.Debugger>) {
-			log(...args);
+			contextLog(log)(...args);
 			webhook
 				.send({
 					username: log.namespace,
 					content: escapeMarkdown(util.format(...args)),
 					allowedMentions: { parse: [] }
 				})
 				.catch(error => {
-					log("Failed to notify webhook.", error);
+					contextLog(log)("Failed to notify webhook.", error);
 				});
 		};
 	} else {
-		return log;
+		return contextLog(log);
 	}
 }