Capture logs from NestJS loggers

itssimon · itssimon · commit f3f5058687b7 · 2025-08-11T22:35:45.000+10:00
diff --git a/src/common/console.ts b/src/common/console.ts
@@ -0,0 +1,39 @@
+import { AsyncLocalStorage } from "async_hooks";
+import { format } from "util";
+
+import { LogRecord } from "./requestLogger.js";
+
+type LogLevel = "log" | "warn" | "error" | "info" | "debug";
+
+let isPatched = false;
+let globalLogsContext: AsyncLocalStorage<LogRecord[]>;
+
+export function patchConsole(logsContext: AsyncLocalStorage<LogRecord[]>) {
+  globalLogsContext = logsContext;
+
+  if (isPatched) {
+    return;
+  }
+
+  const logMethods: LogLevel[] = ["log", "warn", "error", "info", "debug"];
+  logMethods.forEach((method) => {
+    const originalMethod = console[method];
+    console[method] = function (...args: any[]) {
+      captureLog(method, args);
+      return originalMethod.apply(console, args);
+    };
+  });
+
+  isPatched = true;
+}
+
+function captureLog(level: LogLevel, args: any[]) {
+  const logs = globalLogsContext?.getStore();
+  if (logs) {
+    logs.push({
+      timestamp: Date.now() / 1000,
+      level,
+      message: format(...args),
+    });
+  }
+}
diff --git a/src/common/consoleCapture.ts b/src/common/consoleCapture.ts
diff --git a/src/common/requestLogger.ts b/src/common/requestLogger.ts
@@ -88,6 +88,7 @@ export type Response = {
 
 export type LogRecord = {
   timestamp: number;
+  logger?: string;
   level: string;
   message: string;
 };
@@ -393,6 +394,7 @@ export default class RequestLogger {
     if (logs && logs.length > 0) {
       item.logs = logs.map((log) => ({
         timestamp: log.timestamp,
+        logger: log.logger,
         level: log.level,
         message: truncateLogMessage(log.message),
       }));
diff --git a/src/express/middleware.ts b/src/express/middleware.ts
@@ -3,7 +3,7 @@ import { performance } from "perf_hooks";
 
 import { AsyncLocalStorage } from "async_hooks";
 import { ApitallyClient } from "../common/client.js";
-import { patchConsole } from "../common/consoleCapture.js";
+import { patchConsole } from "../common/console.js";
 import { consumerFromStringOrObject } from "../common/consumerRegistry.js";
 import { parseContentLength } from "../common/headers.js";
 import { getPackageVersion } from "../common/packageVersions.js";
@@ -57,6 +57,14 @@ function getMiddleware(app: Express | Router, client: ApitallyClient) {
 
   if (client.requestLogger.config.captureLogs) {
     patchConsole(logsContext);
+
+    import("../nestjs/logger.js")
+      .then(({ patchNestLogger }) => {
+        patchNestLogger(logsContext);
+      })
+      .catch(() => {
+        // ignore
+      });
   }
 
   return (req: Request, res: Response, next: NextFunction) => {
diff --git a/src/fastify/plugin.ts b/src/fastify/plugin.ts
@@ -8,7 +8,7 @@ import type {
 import fp from "fastify-plugin";
 
 import { ApitallyClient } from "../common/client.js";
-import { patchConsole } from "../common/consoleCapture.js";
+import { patchConsole } from "../common/console.js";
 import { consumerFromStringOrObject } from "../common/consumerRegistry.js";
 import { parseContentLength } from "../common/headers.js";
 import { getPackageVersion } from "../common/packageVersions.js";
@@ -54,6 +54,14 @@ const apitallyPlugin: FastifyPluginAsync<ApitallyConfig> = async (
   if (client.requestLogger.config.captureLogs) {
     patchConsole(logsContext);
     patchPino(fastify.log, logsContext, filterLogs);
+
+    try {
+      const { patchNestLogger } = await import("../nestjs/logger.js");
+      patchNestLogger(logsContext);
+      console.log("NestJS logger patched");
+    } catch (error) {
+      // ignore
+    }
   }
 
   fastify.decorateRequest("apitallyConsumer", null);
@@ -224,11 +232,15 @@ const apitallyPlugin: FastifyPluginAsync<ApitallyConfig> = async (
 function getAppInfo(routes: PathInfo[], appVersion?: string) {
   const versions = [["nodejs", process.version.replace(/^v/, "")]];
   const fastifyVersion = getPackageVersion("fastify");
+  const pinoVersion = getPackageVersion("pino");
   const nestjsVersion = getPackageVersion("@nestjs/core");
   const apitallyVersion = getPackageVersion("../..");
   if (fastifyVersion) {
     versions.push(["fastify", fastifyVersion]);
   }
+  if (pinoVersion) {
+    versions.push(["pino", pinoVersion]);
+  }
   if (nestjsVersion) {
     versions.push(["nestjs", nestjsVersion]);
   }
diff --git a/src/hono/middleware.ts b/src/hono/middleware.ts
@@ -4,7 +4,7 @@ import { performance } from "perf_hooks";
 
 import { AsyncLocalStorage } from "async_hooks";
 import { ApitallyClient } from "../common/client.js";
-import { patchConsole } from "../common/consoleCapture.js";
+import { patchConsole } from "../common/console.js";
 import { consumerFromStringOrObject } from "../common/consumerRegistry.js";
 import { parseContentLength } from "../common/headers.js";
 import { convertHeaders, LogRecord } from "../common/requestLogger.js";
diff --git a/src/koa/middleware.ts b/src/koa/middleware.ts
@@ -2,7 +2,7 @@ import Koa from "koa";
 
 import { AsyncLocalStorage } from "async_hooks";
 import { ApitallyClient } from "../common/client.js";
-import { patchConsole } from "../common/consoleCapture.js";
+import { patchConsole } from "../common/console.js";
 import { consumerFromStringOrObject } from "../common/consumerRegistry.js";
 import { getPackageVersion } from "../common/packageVersions.js";
 import {
diff --git a/src/nestjs/logger.ts b/src/nestjs/logger.ts
@@ -0,0 +1,59 @@
+import { Logger } from "@nestjs/common";
+import { AsyncLocalStorage } from "async_hooks";
+import { format } from "util";
+
+import { LogRecord } from "../common/requestLogger.js";
+
+type LogLevel = "log" | "error" | "warn" | "debug" | "verbose" | "fatal";
+
+let isPatched = false;
+let globalLogsContext: AsyncLocalStorage<LogRecord[]>;
+
+export function patchNestLogger(logsContext: AsyncLocalStorage<LogRecord[]>) {
+  globalLogsContext = logsContext;
+
+  if (isPatched) {
+    return;
+  }
+
+  const logMethods: LogLevel[] = [
+    "log",
+    "error",
+    "warn",
+    "debug",
+    "verbose",
+    "fatal",
+  ];
+
+  // Patch static methods
+  logMethods.forEach((method) => {
+    const originalMethod = Logger[method];
+    Logger[method] = function (message: any, ...args: any[]) {
+      captureLog(method, [message, ...args]);
+      return originalMethod.apply(Logger, [message, ...args]);
+    };
+  });
+
+  // Patch prototype methods to affect all instances (new and existing)
+  logMethods.forEach((method) => {
+    const originalMethod = Logger.prototype[method];
+    Logger.prototype[method] = function (message: any, ...args: any[]) {
+      captureLog(method, [message, ...args], this.context);
+      return originalMethod.apply(this, [message, ...args]);
+    };
+  });
+
+  isPatched = true;
+}
+
+function captureLog(level: LogLevel, args: any[], context?: string) {
+  const logs = globalLogsContext?.getStore();
+  if (logs) {
+    logs.push({
+      timestamp: Date.now() / 1000,
+      logger: context,
+      level,
+      message: format(...args),
+    });
+  }
+}
diff --git a/tests/nestjs-express/app.controller.ts b/tests/nestjs-express/app.controller.ts
@@ -6,6 +6,7 @@ import {
   Get,
   Header,
   Injectable,
+  Logger,
   Param,
   ParseIntPipe,
   Post,
@@ -47,9 +48,12 @@ export class HelloBodyDTO {
 @Controller()
 @UseGuards(AuthGuard)
 export class AppController {
+  private readonly logger = new Logger(AppController.name);
+
   @Get("/hello")
   @Header("Content-Type", "text/plain")
   getHello(@Query() { name, age }: HelloQueryDTO) {
+    this.logger.log("Saying hello", { name, age });
     return `Hello ${name}! You are ${age} years old!`;
   }
 
diff --git a/tests/nestjs-express/app.module.ts b/tests/nestjs-express/app.module.ts
@@ -1,4 +1,5 @@
 import { Module } from "@nestjs/common";
+
 import { AppController } from "./app.controller.js";
 
 @Module({
diff --git a/tests/nestjs-express/app.test.ts b/tests/nestjs-express/app.test.ts
@@ -83,6 +83,11 @@ describe("Middleware for NestJS (Express)", () => {
     ]);
     expect(call[1].body).toBeInstanceOf(Buffer);
     expect(call[1].body!.toString()).toMatch(/^Hello John!/);
+    expect(call[3]).toBeDefined();
+    expect(call[3]).toHaveLength(1);
+    expect(call[3]![0].logger).toBe("AppController");
+    expect(call[3]![0].level).toBe("log");
+    expect(call[3]![0].message).toMatch(/^Saying hello/);
     spy.mockReset();
 
     await appTest.post("/hello").send({ name: "John", age: 20 }).expect(201);
diff --git a/tests/nestjs-express/app.ts b/tests/nestjs-express/app.ts
@@ -30,6 +30,7 @@ export async function getApp() {
       logRequestBody: true,
       logResponseHeaders: true,
       logResponseBody: true,
+      captureLogs: true,
     },
   });
 
diff --git a/tests/nestjs-fastify/app.controller.ts b/tests/nestjs-fastify/app.controller.ts
@@ -6,13 +6,15 @@ import {
   Get,
   Header,
   Injectable,
+  Logger,
   Param,
   ParseIntPipe,
   Post,
   Query,
   UseGuards,
 } from "@nestjs/common";
 import { IsInt, IsNotEmpty, Min, MinLength } from "class-validator";
+
 import { setConsumer } from "../../src/nestjs/index.js";
 
 @Injectable()
@@ -47,9 +49,12 @@ export class HelloBodyDTO {
 @Controller()
 @UseGuards(AuthGuard)
 export class AppController {
+  private readonly logger = new Logger(AppController.name);
+
   @Get("/hello")
   @Header("Content-Type", "text/plain")
   getHello(@Query() { name, age }: HelloQueryDTO) {
+    this.logger.log("Saying hello", { name, age });
     return `Hello ${name}! You are ${age} years old!`;
   }
 
diff --git a/tests/nestjs-fastify/app.module.ts b/tests/nestjs-fastify/app.module.ts
@@ -1,4 +1,5 @@
 import { Module } from "@nestjs/common";
+
 import { AppController } from "./app.controller.js";
 
 @Module({
diff --git a/tests/nestjs-fastify/app.test.ts b/tests/nestjs-fastify/app.test.ts
@@ -84,6 +84,11 @@ describe("Middleware for NestJS (Fastify)", () => {
     expect(call[1].headers).toContainEqual(["content-type", "text/plain"]);
     expect(call[1].body).toBeInstanceOf(Buffer);
     expect(call[1].body!.toString()).toMatch(/^Hello John!/);
+    expect(call[3]).toBeDefined();
+    expect(call[3]).toHaveLength(1);
+    expect(call[3]![0].logger).toBe("AppController");
+    expect(call[3]![0].level).toBe("log");
+    expect(call[3]![0].message).toMatch(/^Saying hello/);
     spy.mockReset();
 
     await appTest.post("/hello").send({ name: "John", age: 20 }).expect(201);
diff --git a/tests/nestjs-fastify/app.ts b/tests/nestjs-fastify/app.ts
@@ -31,6 +31,7 @@ export async function getApp() {
       logRequestBody: true,
       logResponseHeaders: true,
       logResponseBody: true,
+      captureLogs: true,
     },
   });
 

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`import { Module } from "@nestjs/common";`
	`2`	`+`
`2`	`3`	`import { AppController } from "./app.controller.js";`
`3`	`4`
`4`	`5`	`@Module({`