add dev command

Author: sommeeeer

packages/open-next/src/build.ts

@@ -1,3 +1,5 @@
+import { spawnSync } from "node:child_process";
+import path from "node:path";
 import url from "node:url";
 
 import {
@@ -25,6 +27,7 @@ export type PublicFiles = {
 export async function build(
   openNextConfigPath?: string,
   nodeExternals?: string,
+  dev = false,
 ) {
   showWarningOnWindows();
 
@@ -35,6 +38,7 @@ export async function build(
     baseDir,
     openNextConfigPath,
     { nodeExternals },
+    dev,
   );
 
   // Initialize options
@@ -80,4 +84,24 @@ export async function build(
   await createWarmerBundle(options);
   await generateOutput(options);
   logger.info("OpenNext build complete.");
+
+  if (dev) {
+    printHeader("Starting development server");
+    spawnSync(
+      "node",
+      [
+        path.join(
+          options.outputDir,
+          "server-functions",
+          "default",
+          "index.mjs",
+        ),
+      ],
+      {
+        stdio: "inherit",
+        shell: process.platform === "win32",
+      },
+    );
+    process.exit(0);
+  }
 }

packages/open-next/src/build/compileConfig.ts

@@ -6,6 +6,7 @@ import { buildSync } from "esbuild";
 import type { OpenNextConfig } from "types/open-next.js";
 
 import logger from "../logger.js";
+import { buildDevConfig } from "./helper.js";
 import { validateConfig } from "./validateConfig.js";
 
 /**
@@ -23,6 +24,7 @@ export async function compileOpenNextConfig(
   baseDir: string,
   openNextConfigPath?: string,
   { nodeExternals = "", compileEdge = false } = {},
+  dev = false,
 ) {
   const sourcePath = path.join(
     baseDir,
@@ -34,6 +36,7 @@ export async function compileOpenNextConfig(
     sourcePath,
     buildDir,
     nodeExternals.split(","),
+    dev,
   );
 
   // On Windows, we need to use file:// protocol to load the config file using import()
@@ -69,10 +72,16 @@ export function compileOpenNextConfigNode(
   sourcePath: string,
   outputDir: string,
   externals: string[],
+  dev = false,
 ) {
   const outputPath = path.join(outputDir, "open-next.config.mjs");
   logger.debug("Compiling open-next.config.ts for Node.", outputPath);
 
+  if (dev) {
+    buildDevConfig(outputPath, externals);
+    return outputPath;
+  }
+
   //Check if open-next.config.ts exists
   if (!fs.existsSync(sourcePath)) {
     //Create a simple open-next.config.mjs file

packages/open-next/src/build/constant.ts

@@ -1,3 +1,29 @@
 //TODO: Move all other manifest path here as well
 export const MIDDLEWARE_TRACE_FILE = "server/middleware.js.nft.json";
 export const INSTRUMENTATION_TRACE_FILE = "server/instrumentation.js.nft.json";
+
+// This is an OpenNext config to run the default server function locally
+// https://opennext.js.org/aws/contribute/local_run
+export const DEV_CONFIG = `
+export default {
+  default: {
+    override: {
+      wrapper: "express-dev",
+      converter: "node",
+      incrementalCache: "fs-dev",
+      queue: "direct",
+      tagCache: "fs-dev",
+    },
+  },
+  imageOptimization: {
+    override: {
+      wrapper: "dummy",
+      converter: "dummy",
+    },
+    loader: "fs-dev",
+    install: {
+      arch: "x64",
+      packages: ["sharp"],
+    },
+  },
+}`;

packages/open-next/src/build/helper.ts

@@ -11,6 +11,7 @@ import type {
 } from "types/open-next.js";
 
 import logger from "../logger.js";
+import { DEV_CONFIG } from "./constant.js";
 
 const require = createRequire(import.meta.url);
 const __dirname = url.fileURLToPath(new URL(".", import.meta.url));
@@ -440,3 +441,28 @@ export async function isEdgeRuntime(
 export function getPackagePath(options: BuildOptions) {
   return path.relative(options.monorepoRoot, options.appBuildOutputPath);
 }
+
+export function buildDevConfig(outputPath: string, externals: string[]) {
+  buildSync({
+    stdin: {
+      contents: DEV_CONFIG,
+      resolveDir: process.cwd(),
+      loader: "ts",
+      sourcefile: "open-next.config.ts",
+    },
+    outfile: outputPath,
+    bundle: true,
+    format: "esm",
+    target: ["node18"],
+    external: externals,
+    platform: "node",
+    banner: {
+      js: [
+        "import { createRequire as topLevelCreateRequire } from 'module';",
+        "const require = topLevelCreateRequire(import.meta.url);",
+        "import bannerUrl from 'url';",
+        "const __dirname = bannerUrl.fileURLToPath(new URL('.', import.meta.url));",
+      ].join(""),
+    },
+  });
+}

packages/open-next/src/index.ts

@@ -3,12 +3,16 @@
 import { build } from "./build.js";
 
 const command = process.argv[2];
-if (command !== "build") printHelp();
+if (command !== "build" && command !== "dev") printHelp();
 
 const args = parseArgs();
 if (Object.keys(args).includes("--help")) printHelp();
 
-await build(args["--config-path"], args["--node-externals"]);
+if (command === "dev") {
+  await build(undefined, args["--node-externals"], true);
+} else if (command === "build") {
+  await build(args["--config-path"], args["--node-externals"]);
+}
 
 function parseArgs() {
   return process.argv.slice(2).reduce(