Replace existing running instance, if any

Summary:
Replace an existing running instance, if any.

This is useful for:
- Applying updates
- Ensuring freshness of server

Reviewed By: passy

Differential Revision: D46146814

fbshipit-source-id: bfb760f3ab26b7632510773609f1c6ca3a97c4ec

desktop/flipper-server/package.json

@@ -17,12 +17,14 @@
     "flipper-pkg-lib": "0.0.0",
     "flipper-server-companion": "0.0.0",
     "flipper-server-core": "0.0.0",
+    "flipper-server-client": "0.0.0",
     "fs-extra": "^11.1.0",
     "http-proxy": "^1.18.1",
     "metro": "^0.70.2",
     "open": "^8.3.0",
     "p-filter": "^2.1.0",
-    "ws": "^8.5.0",
+    "ws": "8.8.0",
+    "reconnecting-websocket": "^4.4.0",
     "xdg-basedir": "^4",
     "yargs": "^17.6.2"
   },

desktop/flipper-server/src/index.tsx

@@ -28,6 +28,12 @@ import {isTest} from 'flipper-common';
 import exitHook from 'exit-hook';
 import {getAuthToken} from 'flipper-server-core';
 import {findInstallation} from './findInstallation';
+import ReconnectingWebSocket from 'reconnecting-websocket';
+import {
+  createFlipperServerWithSocket,
+  FlipperServerState,
+} from 'flipper-server-client';
+import WS from 'ws';
 
 const argv = yargs
   .usage('yarn flipper-server [args]')
@@ -71,6 +77,11 @@ const argv = yargs
       type: 'boolean',
       default: true,
     },
+    replace: {
+      describe: 'Replaces any running instance, if any.',
+      type: 'boolean',
+      default: true,
+    },
   })
   .version('DEV')
   .help()
@@ -87,6 +98,41 @@ const rootPath = argv.bundler
   : path.resolve(__dirname, '..'); // in pre packaged versions of the server, static is copied inside the package
 const staticPath = path.join(rootPath, 'static');
 
+async function connectToRunningServer(url: URL) {
+  console.info(`[flipper-server] Obtain connection to existing server.`);
+  console.info(`[flipper-server] URL: ${url}`);
+  const options = {
+    WebSocket: class WSWithUnixDomainSocketSupport extends WS {
+      constructor(url: string, protocols: string | string[]) {
+        // Flipper exports could be large, and we snd them over the wire
+        // Setting this limit fairly high (1GB) to allow any reasonable Flipper export to be loaded
+        super(url, protocols, {maxPayload: 1024 * 1024 * 1024});
+      }
+    },
+  };
+  const socket = new ReconnectingWebSocket(url.toString(), [], options);
+  const server = await createFlipperServerWithSocket(
+    socket as WebSocket,
+    (_state: FlipperServerState) => {},
+  );
+  return server;
+}
+
+async function shutdown() {
+  console.info('[flipper-server] Attempt to shutdown.');
+
+  const tokenPath = path.resolve(staticPath, 'auth.token');
+  const token = await fs.readFile(tokenPath, 'utf-8');
+
+  const searchParams = new URLSearchParams({token: token ?? ''});
+  const url = new URL(`ws://localhost:${argv.port}?${searchParams}`);
+  const server = await connectToRunningServer(url);
+  await server.exec('shutdown').catch(() => {
+    /** shutdown will ultimately make this request fail, ignore error. */
+    console.info('[flipper-server] Shutdown may have succeeded');
+  });
+}
+
 async function start() {
   const enhanceLogger = await initializeLogger(staticPath);
 
@@ -119,8 +165,14 @@ async function start() {
   );
 
   if (await checkPortInUse(argv.port)) {
-    console.warn(`[flipper-server] Port ${argv.port} is already in use`);
+    console.warn(`[flipper-server] Port ${argv.port} is already in use.`);
-    return;
+    if (!argv.replace) {
+      console.info(
+        `[flipper-server] Not replacing existing instance, exiting.`,
+      );
+      return;
+    }
+    await shutdown();
   }
 
   const {app, server, socket, readyForIncomingConnections} = await startServer({

desktop/flipper-server/tsconfig.json

@@ -3,7 +3,7 @@
   "compilerOptions": {
     "outDir": "lib",
     "rootDir": "src",
-    "lib": ["ES2019"],
+    "lib": ["DOM", "ES2019"],
     "types": ["../types/flipperGlobals", "../types/metro-resolver", "../types/metro"]
   },
   "include": ["./src/*"],
@@ -17,6 +17,9 @@
     {
       "path": "../flipper-server-companion"
     },
+    {
+      "path": "../flipper-server-client"
+    },
     {
       "path": "../pkg-lib"
     }

desktop/scripts/build-flipper-server-release.tsx

@@ -252,6 +252,7 @@ async function linkLocalDeps(buildFolder: string) {
     'flipper-common': `file:${rootDir}/flipper-common`,
     'flipper-frontend-core': `file:${rootDir}/flipper-frontend-core`,
     'flipper-plugin-core': `file:${rootDir}/flipper-plugin-core`,
+    'flipper-server-client': `file:${rootDir}/flipper-server-client`,
     'flipper-server-companion': `file:${rootDir}/flipper-server-companion`,
     'flipper-server-core': `file:${rootDir}/flipper-server-core`,
     'flipper-pkg-lib': `file:${rootDir}/pkg-lib`,

desktop/yarn.lock

@@ -15434,7 +15434,7 @@ ws@^7.0.0, ws@^7.4.5, ws@^7.5.1:
   resolved "https://registry.yarnpkg.com/ws/-/ws-7.5.7.tgz#9e0ac77ee50af70d58326ecff7e85eb3fa375e67"
   integrity sha512-KMvVuFzpKBuiIXW3E4u3mySRO2/mCHSyZDJQM5NQ9Q9KHWHWh0NHgfbRMLLrceUK5qAL4ytALJbpRMjixFZh8A==
 
-ws@^8.5.0, ws@^8.6.0:
+ws@^8.6.0:
   version "8.6.0"
   resolved "https://registry.yarnpkg.com/ws/-/ws-8.6.0.tgz#e5e9f1d9e7ff88083d0c0dd8281ea662a42c9c23"
   integrity sha512-AzmM3aH3gk0aX7/rZLYvjdvZooofDu3fFOzGqcSnQ1tOcTWwhM/o+q++E8mAyVVIyUdajrkzWUGftaVSDLn1bw==