refactor: put request logger into asynclocalstorage

Author: shiftinv

deno.lock

@@ -0,0 +1,25 @@
+import { createMiddleware } from "@hono/hono/factory";
+import { AsyncLocalStorage } from "node:async_hooks";
+
+import { RequestLog, requestLog } from "./util.ts";
+
+interface ContextData {
+    requestLog: RequestLog;
+}
+
+const store = new AsyncLocalStorage<ContextData>();
+
+export const contextMiddleware = createMiddleware(async (c, next) => {
+    const deliveryId = c.req.header("x-github-delivery");
+    const reqLog = requestLog(deliveryId);
+
+    await store.run({ requestLog: reqLog }, next);
+});
+
+export const getContext = () => {
+    const ctx = store.getStore();
+    if (ctx === undefined) throw new Error("getContext() may only be called in request handlers");
+    return ctx;
+};
+
+export const getRequestLog = () => getContext().requestLog;

src/context.ts

@@ -1,13 +1,13 @@
+import { getRequestLog } from "./context.ts";
 import { getAndIncrementKV } from "./kv.ts";
 import { UrlConfig } from "./types.d.ts";
-import { requestLog, wildcardMatch } from "./util.ts";
+import { wildcardMatch } from "./util.ts";
 
 export default async function filter(
     headers: Record<string, string>,
     json: any,
     config: UrlConfig,
 ): Promise<string | null> {
-    const reqLog = requestLog(headers);
     const event = headers["x-github-event"] || "unknown";
     const login: string | undefined = json.sender?.login?.toLowerCase();
 
@@ -51,6 +51,7 @@ export default async function filter(
         if (config.commentBurstLimit && reviewId) {
             const cacheKey = `${reviewId}-${login}`;
 
+            const reqLog = getRequestLog();
             reqLog.debug(`filter: checking cache key ${cacheKey}`);
             const curr = await getAndIncrementKV(cacheKey, reqLog);
             reqLog.debug(`filter: current value: ${curr}`);

src/filter.ts

@@ -1,9 +1,10 @@
 import { HTTPException } from "@hono/hono/http-exception";
 
+import { getRequestLog } from "./context.ts";
 import filterWebhook from "./filter.ts";
 import fixupEmbeds from "./formatter.ts";
 import { UrlConfig } from "./types.d.ts";
-import { parseBool, requestLog } from "./util.ts";
+import { parseBool } from "./util.ts";
 import { sendWebhook } from "./webhook.ts";
 
 export default async function handle(
@@ -18,7 +19,7 @@ export default async function handle(
     // do the thing
     const filterReason = await filterWebhook(headers, json, urlConfig);
     if (filterReason !== null) {
-        const reqLog = requestLog(headers);
+        const reqLog = getRequestLog();
         reqLog.debug(`handler: ignored due to '${filterReason}'`);
         return [
             new Response(`Ignored by webhook filter (reason: ${filterReason})`, { status: 203 }),

src/handler.ts

@@ -3,12 +3,14 @@ import { HTTPException } from "@hono/hono/http-exception";
 import { logger } from "@hono/hono/logger";
 
 import config from "./config.ts";
+import { contextMiddleware } from "./context.ts";
 import { hasKey, verify } from "./crypto.ts";
 import handler from "./handler.ts";
 
 const app = new Hono();
 
 app.use(logger());
+app.use(contextMiddleware);
 
 if (config.mainRedirect) {
     app.get("/", (c) => {

src/main.ts

@@ -31,8 +31,7 @@ export function wildcardMatch(pattern: string, target: string): boolean {
 /**
  * logging proxy that adds some metadata to log messages
  */
-export function requestLog(headers: Record<string, string>) {
-    const deliveryId = headers["x-github-delivery"];
+export function requestLog(deliveryId: string | undefined) {
     const prefix = deliveryId ? `[${deliveryId}] ` : "";
 
     // ugh

src/util.ts

@@ -1,13 +1,14 @@
 import config from "./config.ts";
-import { requestLog, sleep } from "./util.ts";
+import { getRequestLog } from "./context.ts";
+import { sleep } from "./util.ts";
 
 export async function sendWebhook(
     id: string,
     token: string,
     headers: Record<string, string>,
     data: Record<string, any>,
 ): Promise<[Response, Record<string, string>]> {
-    const reqLog = requestLog(headers);
+    const reqLog = getRequestLog();
     const url = `https://discord.com/api/webhooks/${id}/${token}/github?wait=1`;
     const body = JSON.stringify(data);