Client should throw when server unexpectedly closes the connection

Reviewed By: @natthu

Differential Revision: D2425357

react-packager/src/Server/index.js

@@ -157,6 +157,7 @@ class Server {
   }
 
   buildBundle(options) {
+    return Promise.resolve().then(() => {
       const opts = bundleOpts(options);
       return this._bundler.bundle(
         opts.entryFile,
@@ -165,6 +166,7 @@ class Server {
         opts.dev,
         opts.platform
       );
+    });
   }
 
   buildBundleFromUrl(reqUrl) {

react-packager/src/SocketInterface/SocketClient.js

@@ -33,10 +33,7 @@ class SocketClient {
       this._sock.on('error', (e) => {
         e.message = `Error connecting to server on ${sockPath} ` +
                     `with error: ${e.message}`;
-
+        e.message += getServerLogs();
-        if (fs.existsSync(LOG_PATH)) {
-          e.message += '\nServer logs:\n' + fs.readFileSync(LOG_PATH, 'utf8');
-        }
 
         reject(e);
       });
@@ -45,8 +42,13 @@ class SocketClient {
     this._resolvers = Object.create(null);
     const bunser = new bser.BunserBuf();
     this._sock.on('data', (buf) => bunser.append(buf));
-
     bunser.on('value', (message) => this._handleMessage(message));
+
+    this._sock.on('close', () => {
+      if (!this._closing) {
+        throw new Error('Server closed unexpectedly' + getServerLogs());
+      }
+    });
   }
 
   onReady() {
@@ -105,6 +107,7 @@ class SocketClient {
 
   close() {
     debug('closing connection');
+    this._closing = true;
     this._sock.end();
   }
 }
@@ -115,3 +118,11 @@ function uid(len) {
   len = len || 7;
   return Math.random().toString(35).substr(2, len);
 }
+
+function getServerLogs() {
+  if (fs.existsSync(LOG_PATH)) {
+    return '\nServer logs:\n' + fs.readFileSync(LOG_PATH, 'utf8');
+  }
+
+  return '';
+}

react-packager/src/SocketInterface/SocketServer.js

@@ -59,7 +59,12 @@ class SocketServer {
     const bunser = new bser.BunserBuf();
     sock.on('data', (buf) => bunser.append(buf));
     bunser.on('value', (m) => this._handleMessage(sock, m));
-    bunser.on('error', (e) => console.error(e));
+    bunser.on('error', (e) => {
+      e.message = 'Unhandled error from the bser buffer. ' +
+                  'Either error on encoding or message handling: \n' +
+                  e.message;
+      throw e;
+    });
   }
 
   _handleMessage(sock, m) {