refactor(child-process): IPC via stdio

examples/child-process/src/lib/vite/bridge-client.js

@@ -1,6 +1,9 @@
 // @ts-check
 
 import assert from "node:assert";
+import fs from "node:fs";
+import readline from "node:readline";
+import { Writable } from "node:stream";
 import { ESModulesEvaluator, ModuleRunner } from "vite/module-runner";
 
 /**
@@ -22,12 +25,39 @@ export function createBridgeClient(options) {
     return result;
   }
 
+  // TODO: birpc
+  const childIn = readline.createInterface(process.stdin);
+  const childOut = new Writable({
+    write(chunk, _encoding, callback) {
+      fs.write(3, chunk, callback);
+    },
+  });
+
   const runner = new ModuleRunner(
     {
       root: options.root,
       sourcemapInterceptor: "prepareStackTrace",
       transport: {
-        fetchModule: (...args) => rpc("fetchModule", ...args),
+        fetchModule: async (...args) => {
+          const id = Math.random().toString(36).slice(2);
+          const promise = new Promise((resolve, _reject) => {
+            /**
+             * @param {string} line
+             */
+            function handler(line) {
+              const event = JSON.parse(line);
+              if (event.id === id) {
+                childIn.off("line", handler);
+                resolve(event.result);
+              }
+            }
+            childIn.on("line", handler);
+          });
+          childOut.write(
+            JSON.stringify({ type: "fetchModule", id, args }) + "\n",
+          );
+          return promise;
+        },
       },
       hmr: false,
     },

examples/child-process/src/lib/vite/environment.ts

@@ -3,7 +3,7 @@ import childProcess from "node:child_process";
 import http from "node:http";
 import { join } from "node:path";
 import readline from "node:readline";
-import { Readable } from "node:stream";
+import { Readable, Writable } from "node:stream";
 import { webToNodeHandler } from "@hiogawa/utils-node";
 import { DevEnvironment, type DevEnvironmentOptions } from "vite";
 import type { BridgeClientOptions } from "./types";
@@ -101,11 +101,13 @@ export class ChildProcessFetchDevEnvironment extends DevEnvironment {
         // 4th stdio to ease startup communication
         // TODO: use 1st stdio to make bidirection?
         // https://github.com/cloudflare/workers-sdk/blob/e5037b92ac13b1b8a94434e1f9bfa70d4abf791a/packages/miniflare/src/runtime/index.ts#L141
-        stdio: ["ignore", "inherit", "inherit", "pipe"],
+        stdio: ["pipe", "inherit", "inherit", "pipe"],
       },
     );
     this.child = child;
+    assert(child.stdio[0] instanceof Writable);
     assert(child.stdio[3] instanceof Readable);
+    const childIn = child.stdio[0];
     this.childIO = readline.createInterface(child.stdio[3]);
     await new Promise<void>((resolve, reject) => {
       const timeout = setTimeout(
@@ -128,6 +130,14 @@ export class ChildProcessFetchDevEnvironment extends DevEnvironment {
         }
       });
     });
+    this.childIO.on("line", async (line) => {
+      const event = JSON.parse(line);
+      if (event.type === "fetchModule") {
+        const { id, args } = event;
+        const result = await this.fetchModule(...(args as [any]));
+        childIn.write(JSON.stringify({ id, result }) + "\n");
+      }
+    });
     console.log("[environment.init]", {
       bridgeUrl: this.bridgeUrl,
       childUrl: this.childUrl,