refactor(desktop): 使用预分配端口替代 stdout 解析获取服务器端口

apps/desktop/AGENTS.md

@@ -62,8 +62,9 @@ The desktop build is orchestrated by Turbo. It depends on the server's productio
 ### Server Lifecycle
 In production, the main process manages the embedded server:
 - **Spawn**: Spawns server from `server-output/server/index.mjs` using `Bun.spawn`.
-- **Port Allocation**: Server is started with `PORT=0` and `HOST=127.0.0.1`.
-- **Port Detection**: The main process parses the server's `stdout` using a regex to find the dynamically assigned port.
+- **Port Allocation**: A free port is pre-allocated via `node:net` (`createServer` on `127.0.0.1:0`), then passed to the server as the `PORT` environment variable.
+- **Readiness Check**: The main process polls the server URL with `fetch` until it responds, rather than parsing stdout.
+- **Retry**: If the server fails to become ready (timeout or early exit), the process is killed and a new attempt is made with a fresh port (up to 3 retries).
 - **Lifecycle**: The server process is tied to the app; it is killed on `SIGTERM`, `SIGINT`, or app exit. If the server process crashes, the app exits with an error.
 
 ## Environment Detection
@@ -119,7 +120,7 @@ const serverEntryPath = join(PATHS.VIEWS_FOLDER, '..', 'server-output', 'server'
 **DO:**
 - Use arrow functions for all components and utility functions.
 - Ensure `apps/server` is built before building `apps/desktop` (handled by Turbo).
-- Parse the server's stdout for the port instead of hardcoding ports in production.
+- Pre-allocate a free port and pass it via `PORT` env var instead of parsing stdout.
 - Handle server process termination to avoid orphan processes.
 - Use `catalog:` for all dependency versions in `package.json`.
 

apps/desktop/src/bun/index.ts

@@ -1,9 +1,10 @@
+import { createServer } from 'node:net'
 import { dirname, join } from 'node:path'
 import { BrowserWindow, PATHS } from 'electrobun/bun'
 
 const DEV_SERVER_URL = 'http://localhost:3000'
-const SERVER_READY_TIMEOUT_MS = 30_000
-const PORT_PATTERN = /Listening on:?\s*https?:\/\/[^\s:]+:(\d+)/
+const SERVER_READY_TIMEOUT_MS = 5_000
+const MAX_SPAWN_RETRIES = 3
 
 const isDev = (): boolean => {
   const env = process.env.ELECTROBUN_BUILD_ENV
@@ -14,6 +15,23 @@ const getServerEntryPath = (): string => {
   return join(PATHS.VIEWS_FOLDER, '..', 'server-output', 'server', 'index.mjs')
 }
 
+const getFreePort = (): Promise<number> => {
+  return new Promise((resolve, reject) => {
+    const srv = createServer()
+    srv.unref()
+    srv.once('error', reject)
+    srv.listen({ port: 0, host: '127.0.0.1', exclusive: true }, () => {
+      const addr = srv.address()
+      if (addr && typeof addr === 'object') {
+        const port = addr.port
+        srv.close((err) => (err ? reject(err) : resolve(port)))
+      } else {
+        srv.close(() => reject(new Error('Unexpected address() result')))
+      }
+    })
+  })
+}
+
 const waitForServer = async (
   url: string,
   timeoutMs = SERVER_READY_TIMEOUT_MS,
@@ -38,64 +56,39 @@ const spawnServer = async (): Promise<{
   const serverEntryPath = getServerEntryPath()
   const serverDir = dirname(serverEntryPath)
 
-  const serverProc = Bun.spawn([process.execPath, serverEntryPath], {
-    cwd: serverDir,
-    env: {
-      ...process.env,
-      PORT: '0',
-      HOST: '127.0.0.1',
-    },
-    stdout: 'pipe',
-    stderr: 'pipe',
-  })
+  for (let attempt = 1; attempt <= MAX_SPAWN_RETRIES; attempt++) {
+    const port = await getFreePort()
+    const url = `http://127.0.0.1:${port}`
 
-  const port = await new Promise<string>((resolve, reject) => {
-    const timeout = setTimeout(() => {
-      serverProc.kill()
-      reject(
-        new Error(`Server did not start within ${SERVER_READY_TIMEOUT_MS}ms`),
-      )
-    }, SERVER_READY_TIMEOUT_MS)
-
-    const reader = serverProc.stdout.getReader()
-    let buffer = ''
-
-    const read = async () => {
-      try {
-        while (true) {
-          const { done, value } = await reader.read()
-          if (done) {
-            clearTimeout(timeout)
-            reject(new Error('Server process exited before reporting port'))
-            return
-          }
-
-          const text = new TextDecoder().decode(value)
-          buffer += text
-          process.stdout.write(text)
-
-          const match = PORT_PATTERN.exec(buffer)
-          if (match?.[1]) {
-            clearTimeout(timeout)
-            resolve(match[1])
-            return
-          }
-        }
-      } catch (err) {
-        clearTimeout(timeout)
-        reject(err)
-      }
-    }
-
-    serverProc.exited.then((code) => {
-      clearTimeout(timeout)
-      reject(new Error(`Server exited with code ${code} before becoming ready`))
+    const serverProc = Bun.spawn([process.execPath, serverEntryPath], {
+      cwd: serverDir,
+      env: {
+        ...process.env,
+        PORT: String(port),
+        HOST: '127.0.0.1',
+      },
+      stdio: ['ignore', 'inherit', 'inherit'],
     })
 
-    read()
-  })
+    const ready = await Promise.race([
+      waitForServer(url),
+      serverProc.exited.then((code) => {
+        throw new Error(`Server exited with code ${code} before becoming ready`)
+      }),
+    ])
 
-  return { process: serverProc, url: `http://127.0.0.1:${port}` }
+    if (ready) {
+      return { process: serverProc, url }
+    }
+
+    serverProc.kill()
+    await serverProc.exited
+    console.warn(
+      `Server failed to become ready on port ${port} (attempt ${attempt}/${MAX_SPAWN_RETRIES})`,
+    )
+  }
+
+  throw new Error(`Server failed to start after ${MAX_SPAWN_RETRIES} attempts`)
 }
 
 const main = async () => {