feat: built-in tracing channel support

examples/tracing/nitro.config.ts

@@ -0,0 +1,6 @@
+import { defineConfig } from "nitro";
+
+export default defineConfig({
+  serverDir: "./server",
+  tracing: true,
+});

examples/tracing/package.json

@@ -0,0 +1,11 @@
+{
+  "type": "module",
+  "scripts": {
+    "build": "nitro build",
+    "dev": "nitro dev",
+    "preview": "node .output/server/index.mjs"
+  },
+  "devDependencies": {
+    "nitro": "latest"
+  }
+}

examples/tracing/server/middleware/test.ts

@@ -0,0 +1 @@
+export default () => {};

examples/tracing/server/plugins/tracing.ts

@@ -0,0 +1,37 @@
+import { definePlugin } from "nitro";
+
+export default definePlugin(() => {});
+
+// --- debug tracing channels ---
+
+debugChannel("srvx.middleware");
+debugChannel("srvx.fetch");
+debugChannel("h3.fetch");
+
+function debugChannel(name: string) {
+  const { tracingChannel } = process.getBuiltinModule("node:diagnostics_channel");
+
+  const log = (...args: unknown[]) => console.log(`[tracing:${name}]`, ...args);
+  const noop = () => {};
+  const serializeData = (data: any) =>
+    Object.entries(data)
+      .map(([key, value]) => {
+        if (!value) {
+          value = String(value);
+        } else if (value instanceof Response) {
+          value = `Response(${value.status} ${value.statusText})`;
+        } else if (typeof value === "object") {
+          value = `{${Object.keys(value).join(",")}}`;
+        }
+        return `${key}=${value}`;
+      })
+      .join(", ");
+
+  tracingChannel(name).subscribe({
+    start: noop,
+    end: noop,
+    asyncStart: (data) => log("asyncStart", serializeData(data)),
+    asyncEnd: (data) => log("asyncEnd", serializeData(data)),
+    error: (data) => log("error", serializeData(data)),
+  });
+}

examples/tracing/server/routes/index.ts

@@ -0,0 +1 @@
+export default () => "Index Page";

examples/tracing/tsconfig.json

@@ -0,0 +1,3 @@
+{
+  "extends": "nitro/tsconfig"
+}

examples/tracing/vite.config.ts

@@ -0,0 +1,4 @@
+import { defineConfig } from "vite";
+import { nitro } from "nitro/vite";
+
+export default defineConfig({ plugins: [nitro()] });

src/build/virtual/_all.ts

@@ -13,6 +13,7 @@ import runtimeConfig from "./runtime-config.ts";
 import serverAssets from "./server-assets.ts";
 import storage from "./storage.ts";
 import tasks from "./tasks.ts";
+import tracing from "./tracing.ts";
 
 type VirtualTemplate = {
   id: string;
@@ -34,6 +35,7 @@ export function virtualTemplates(nitro: Nitro, _polyfills: string[]): VirtualTem
     serverAssets,
     storage,
     tasks,
+    tracing,
   ].flatMap((t) => t(nitro, _polyfills));
 
   const customTemplates = Object.entries(nitro.options.virtual).map(([id, template]) => ({

src/build/virtual/tracing.ts

@@ -0,0 +1,19 @@
+import type { Nitro } from "nitro/types";
+
+export default function tracing(nitro: Nitro) {
+  return {
+    id: "#nitro/virtual/tracing",
+    template: () => {
+      return /* js */ `
+        import { tracingPlugin as h3Tracing } from "h3/tracing";
+        import { tracingPlugin as srvxTracing } from 'srvx/tracing'
+
+        export const tracingSrvxPlugins = ${nitro.options.tracing!.srvx ? "[srvxTracing()]" : "[]"};
+
+        export default function tracing(nitroApp) {
+          h3Tracing()(nitroApp.h3);
+        };
+      `;
+    },
+  };
+}

src/config/loader.ts

@@ -24,6 +24,7 @@ import { resolveURLOptions } from "./resolvers/url.ts";
 import { resolveErrorOptions } from "./resolvers/error.ts";
 import { resolveUnenv } from "./resolvers/unenv.ts";
 import { resolveBuilder } from "./resolvers/builder.ts";
+import { resolveTracingOptions } from "./resolvers/tracing.ts";
 
 const configResolvers = [
   resolveCompatibilityOptions,
@@ -41,6 +42,7 @@ const configResolvers = [
   resolveErrorOptions,
   resolveUnenv,
   resolveBuilder,
+  resolveTracingOptions,
 ] as const;
 
 export async function loadOptions(

src/config/resolvers/tracing.ts

@@ -0,0 +1,12 @@
+import type { NitroOptions } from "nitro/types";
+
+export async function resolveTracingOptions(options: NitroOptions) {
+  if (!options.tracing) return;
+  options.tracing = {
+    srvx: true,
+    h3: true,
+    ...(typeof options.tracing === "object" ? options.tracing : {}),
+  };
+  options.plugins = options.plugins || [];
+  options.plugins.push("#nitro/virtual/tracing");
+}

src/presets/node/runtime/node-server.ts

@@ -6,6 +6,7 @@ import { useNitroApp } from "nitro/app";
 import { startScheduleRunner } from "#nitro/runtime/task";
 import { trapUnhandledErrors } from "#nitro/runtime/error/hooks";
 import { resolveWebsocketHooks } from "#nitro/runtime/app";
+import { tracingSrvxPlugins } from "#nitro/virtual/tracing";
 
 const _parsedPort = Number.parseInt(process.env.NITRO_PORT ?? process.env.PORT ?? "");
 const port = Number.isNaN(_parsedPort) ? 3000 : _parsedPort;
@@ -22,6 +23,7 @@ const server = serve({
   hostname: host,
   tls: cert && key ? { cert, key } : undefined,
   fetch: nitroApp.fetch,
+  plugins: [...tracingSrvxPlugins],
 });
 
 if (import.meta._websocket) {

src/presets/standard/preset.ts

@@ -16,6 +16,7 @@ const standard = defineNitroPreset(
       "srvx/deno": "srvx/deno",
       "srvx/node": "srvx/node",
       "srvx/generic": "srvx/generic",
+      "srvx/tracing": "srvx/tracing",
     },
   },
   {

src/runtime/virtual/tracing.ts

@@ -0,0 +1,8 @@
+import "./_runtime_warn.ts";
+
+import type { NitroAppPlugin } from "nitro/types";
+
+declare const plugin: NitroAppPlugin;
+export default plugin;
+
+export declare const tracingSrvxPlugins: Array<() => any>;

src/types/config.ts

@@ -78,6 +78,7 @@ export interface NitroOptions extends PresetOptions {
   ssrRoutes: string[];
   serveStatic: boolean | "node" | "deno" | "inline";
   noPublicDir: boolean;
+  tracing?: undefined | TracingOptions;
   manifest?: {
     deploymentId?: string;
   };
@@ -291,6 +292,7 @@ export interface NitroConfig
         | "serverEntry"
         | "renderer"
         | "output"
+        | "tracing"
       >
     >,
     C12InputConfig<NitroConfig> {
@@ -304,6 +306,7 @@ export interface NitroConfig
   serverEntry?: string | NitroOptions["serverEntry"];
   renderer?: false | NitroOptions["renderer"];
   output?: Partial<NitroOptions["output"]>;
+  tracing?: boolean | TracingOptions;
 }
 
 // ------------------------------------------------------------
@@ -349,6 +352,11 @@ export interface ServerAssetDir {
   ignore?: string[];
 }
 
+export interface TracingOptions {
+  srvx?: boolean;
+  h3?: boolean;
+}
+
 // Storage mounts
 type CustomDriverName = string & { _custom?: any };
 export interface StorageMounts {