エンジンが使うポートが割り当てできなければ、他の空いているポートで起動してユーザーに通知する

src/background/engineManager.ts

@@ -5,10 +5,11 @@ import treeKill from "tree-kill";
 import Store from "electron-store";
 import shlex from "shlex";
 
-import { BrowserWindow, dialog } from "electron";
+import { app, BrowserWindow, dialog } from "electron";
 
 import log from "electron-log";
 import { z } from "zod";
+import { PortManager } from "./portManager";
 import { ipcMainSend } from "@/electron/ipc";
 
 import {
@@ -209,6 +210,7 @@ export class EngineManager {
     const engineInfo = engineInfos.find(
       (engineInfo) => engineInfo.uuid === engineId
     );
+
     if (!engineInfo)
       throw new Error(`No such engineInfo registered: engineId == ${engineId}`);
 
@@ -224,6 +226,50 @@ export class EngineManager {
       return;
     }
 
+    const engineInfoUrl = new URL(engineInfo.host);
+    const portManager = new PortManager(
+      engineInfoUrl.hostname,
+      parseInt(engineInfoUrl.port)
+    );
+
+    log.info(
+      `ENGINE ${engineId}: Checking whether port ${engineInfoUrl.port} is assignable...`
+    );
+
+    // ポートを既に割り当てられているプロセスidの取得: undefined → ポートが空いている
+    const processId = await portManager.getProcessIdFromPort();
+
+    if (processId !== undefined) {
+      const processName = await portManager.getProcessNameFromPid(processId);
+      log.warn(
+        `ENGINE ${engineId}: Port ${engineInfoUrl.port} has already been assigned by ${processName} (pid=${processId})`
+      );
+
+      const altPort = await portManager.findAltPort();
+
+      // TODO: エディターでトースト通知を出す:
+      // > XXXXX番ポートが使用中であるため、〇〇はYYYYY番ポートで起動しました
+
+      // 代替ポートが見つからないとき
+      if (!altPort) {
+        dialog.showErrorBox(
+          `${engineInfo.name} の起動に失敗しました`,
+          `${engineInfoUrl.port}番ポートの代わりに利用可能なポートが見つかりませんでした。PCを再起動してください。`
+        );
+        app.exit(1);
+        throw new Error("No Alternative Port Found");
+      }
+
+      // 代替ポートを設定
+      engineInfo.host = new PortManager(
+        engineInfoUrl.hostname,
+        altPort
+      ).getUrl();
+      log.warn(
+        `ENGINE ${engineId}: Applied Alternative Port: ${engineInfoUrl.port} -> ${altPort}`
+      );
+    }
+
     log.info(`ENGINE ${engineId}: Starting process`);
 
     if (!(engineId in this.engineProcessContainers)) {
@@ -244,7 +290,12 @@ export class EngineManager {
 
     // エンジンプロセスの起動
     const enginePath = engineInfo.executionFilePath;
-    const args = engineInfo.executionArgs.concat(useGpu ? ["--use_gpu"] : []);
+    const args = engineInfo.executionArgs.concat(useGpu ? ["--use_gpu"] : [], [
+      "--host",
+      new URL(engineInfo.host).hostname,
+      "--port",
+      new URL(engineInfo.host).port,
+    ]);
 
     log.info(`ENGINE ${engineId} path: ${enginePath}`);
     log.info(`ENGINE ${engineId} args: ${JSON.stringify(args)}`);

src/background/portManager.ts

@@ -0,0 +1,137 @@
+import { execFileSync } from "child_process";
+import log from "electron-log";
+
+const isWindows = process.platform === "win32";
+
+export class PortManager {
+  constructor(private hostname: string, private port: number) {}
+
+  /**
+   * ex) url: `http://localhost:50021`
+   *  host -> `localhost`
+   *  port -> `50021`
+   */
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  portLog = (...message: any) => log.info(`PORT ${this.port}: ${message}`);
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  portWarn = (...message: any) => log.warn(`PORT ${this.port}: ${message}`);
+
+  public getUrl(isHttps = false): string {
+    return `${isHttps ? "https" : "http"}://${this.hostname}:${this.port}`;
+  }
+
+  /**
+   * "netstat -ano" の stdout から, 指定したポートを使用しているプロセスの process id を取得する
+   *
+   * ex) stdout:
+   * ``` cmd
+   * TCP  127.0.0.1:5173   127.0.0.1:50170  TIME_WAIT  0
+   * TCP  127.0.0.1:6463   0.0.0.0:0        LISTENING  18692
+   * TCP  127.0.0.1:50021  0.0.0.0:0        LISTENING  17320
+   * ```
+   * -> `17320`
+   *
+   * @param stdout netstat の stdout
+   * @returns `process id` or `undefined` (ポートが使用されていないとき)
+   */
+  private stdout2processId(stdout: string): number | undefined {
+    const lines = stdout.split("\n");
+    for (const line of lines) {
+      if (line.includes(`${this.hostname}:${this.port}`)) {
+        const parts = line.trim().split(/\s+/);
+        return parseInt(parts[parts.length - 1], 10);
+      }
+    }
+    return undefined;
+  }
+
+  async getProcessIdFromPort(): Promise<number | undefined> {
+    this.portLog("Getting process id...");
+    const exec = isWindows
+      ? {
+          cmd: "netstat",
+          args: ["-ano"],
+        }
+      : {
+          cmd: "lsof",
+          args: ["-i", `:${this.port}`, "-t", "-sTCP:LISTEN"],
+        };
+
+    this.portLog(`Running command: "${exec.cmd} ${exec.args.join(" ")}"`);
+
+    let stdout = execFileSync(exec.cmd, exec.args, {
+      shell: true,
+    }).toString();
+
+    // windows
+    if (isWindows) {
+      stdout = this.stdout2processId(stdout)?.toString() ?? "";
+    }
+
+    // bash
+    if (!stdout || !stdout.length) {
+      this.portLog("Assignable; Nobody uses this port!");
+      return undefined;
+    }
+    this.portWarn(`Nonassignable; pid=${stdout} uses this port!`);
+    return parseInt(stdout);
+  }
+
+  async getProcessNameFromPid(pid: number): Promise<string> {
+    this.portLog(`Getting process name from pid=${pid}...`);
+    const exec = isWindows
+      ? // TODO: `TCPポートの除外範囲` というものがあって, そこに該当しているかを確認する
+        {
+          cmd: "wmic",
+          args: ["process", "where", `"ProcessID=${pid}"`, "get", "name"],
+        }
+      : // TODO: MacOS だとroot権限が必要かも？  場合によって, 代替コマンド `ss` や `fuser` を使うかも
+        {
+          cmd: "ps",
+          args: ["-p", pid.toString(), "-o", "comm="],
+        };
+
+    let stdout = execFileSync(exec.cmd, exec.args, { shell: true }).toString();
+
+    if (isWindows) {
+      /*
+       * ex) stdout:
+       * ```
+       * Name
+       * node.exe
+       * ```
+       * -> `node.exe`
+       */
+      stdout = stdout.split("\r\n")[1];
+    }
+
+    this.portLog(`Found process name: ${stdout}`);
+
+    return stdout.trim();
+  }
+
+  /**
+   * 割り当て可能な他のポートを探します
+   *
+   * @returns 割り当て可能なポート番号 or `undefined` (割り当て可能なポートが見つからなかったとき)
+   */
+  async findAltPort(): Promise<number | undefined> {
+    this.portLog(`Find another assignable port from ${this.port}...`);
+    const altPortMax = 50100;
+
+    for (let altPort = this.port + 1; altPort <= altPortMax; altPort++) {
+      this.portLog(`Trying whether port ${altPort} is assignable...`);
+      const altPid = await new PortManager(
+        this.hostname,
+        altPort
+      ).getProcessIdFromPort();
+
+      // ポートを既に割り当てられているプロセスidの取得: undefined → ポートが空いている
+      if (altPid === undefined) return altPort;
+    }
+
+    this.portWarn(`No alternative port found! ${this.port}...${altPortMax}`);
+    return undefined;
+  }
+}