feat(dev): add STRICT_PORT environment variable for port availability check (#12921)

Author: sorrycc

docs/docs/docs/guides/env-variables.en-US.md

@@ -157,6 +157,14 @@ Specifies the socket server for HMR. For example:
 $ SOCKET_SERVER=http://localhost:8000/ umi dev
 ```
 
+### STRICT_PORT
+
+If set, when the port is occupied, it will prompt the user to use another port and exit the process.
+
+```bash
+$ STRICT_PORT=8000 umi dev
+```
+
 ### SPEED_MEASURE
 
 Analyzes the Webpack compile time, supports `CONSOLE` and `JSON` formats, the default is `CONSOLE`.

docs/docs/docs/guides/env-variables.md

@@ -156,6 +156,14 @@ $ ANALYZE=1 umi build
 $ SOCKET_SERVER=http://localhost:8000/ umi dev
 ```
 
+### STRICT_PORT
+
+如果设置，当端口被占用时，会提示用户使用其他端口，并退出进程。
+
+```bash
+$ STRICT_PORT=8000 umi dev
+```
+
 ### SPEED_MEASURE
 
 分析 Webpack 编译时间，支持 `CONSOLE` 和 `JSON` 两种格式，默认是 `CONSOLE`。

packages/preset-umi/src/commands/dev/dev.ts

@@ -78,6 +78,24 @@ PORT=8888 umi dev
       // clear tmp
       rimraf.sync(api.paths.absTmpPath);
 
+      // check strict port
+      if (process.env.STRICT_PORT) {
+        logger.info(
+          `Checking port ${process.env.STRICT_PORT} since STRICT_PORT is set...`,
+        );
+        const port = parseInt(String(process.env.STRICT_PORT), 10);
+        const isPortAvailableResult = await isPortAvailable(port);
+        if (!isPortAvailableResult) {
+          logger.error(
+            `Port ${port} is not available, please use another port.`,
+          );
+          logger.info(
+            `If you don't want to exit when the port is not available, use PORT instead.`,
+          );
+          process.exit(1);
+        }
+      }
+
       // check package.json
       await api.applyPlugins({
         key: 'onCheckPkgJSON',
@@ -488,3 +506,11 @@ PORT=8888 umi dev
     return viteConfig;
   });
 };
+
+async function isPortAvailable(port: number) {
+  const foundPort = await portfinder.getPortPromise({
+    port,
+  });
+  return foundPort === port;
+}
+