(GH-274) Remove random port detection

This commit removes the code that detects and uses a random port for the
LanguageServer to run on. It instead parses the STDOUT message from the
LanguageServer for the port it is running on and uses that to connect.
If the user sets a port in the config, that is used instead of reading
the port from the LanguageServer.

Author: jpogran

src/configuration.ts

@@ -161,7 +161,9 @@ export class ConnectionConfiguration implements IConnectionConfiguration {
         } else {
           args.push('--ip=' + this.host);
         }
-        args.push('--port=' + this.port);
+        if (this.port !== 0) {
+          args.push('--port=' + this.port);
+        }
         break;
       default:
         break;

src/connection.ts

@@ -127,8 +127,14 @@ export class ConnectionManager implements IConnectionManager {
           this.logger.debug('OUTPUT: ' + data.toString());
 
           // If the language client isn't already running and it's sent the trigger text, start up a client
-          if (this.languageServerClient === undefined && data.toString().match('LANGUAGE SERVER RUNNING') !== null) {
-            this.languageServerClient = this.createLanguageClient();
+          if (this.languageServerClient === undefined && /LANGUAGE SERVER RUNNING/.test(data.toString())) {
+            if(this.connectionConfiguration.port){            
+              this.languageServerClient = this.createLanguageClient();
+            }else{
+              var p = data.toString().match(/LANGUAGE SERVER RUNNING.*:(\d+)/);
+              this.connectionConfiguration.port = +p[1];
+              this.languageServerClient = this.createLanguageClient();
+            }
             this.extensionContext.subscriptions.push(this.languageServerClient.start());
           }
         });
@@ -184,26 +190,8 @@ export class ConnectionManager implements IConnectionManager {
     if(this.connectionConfiguration.protocol === ProtocolType.TCP){
       if(this.connectionConfiguration.port){
         this.logger.debug(logPrefix + 'Selected port for local language server: ' + this.connectionConfiguration.port);
-        connMgr.startLanguageServerProcess(localServer.command, localServer.args, localServer.options, callback);
-      }else{
-        // Start a server to get a random port
-        this.logger.debug(logPrefix + 'Creating server process to identify random port');
-        const server = net
-          .createServer()
-          .on('close', () => {
-            this.logger.debug(logPrefix + 'Server process to identify random port disconnected');
-            connMgr.startLanguageServerProcess(localServer.command, localServer.args, localServer.options, callback);
-          })
-          .on('error', err => {
-            throw err;
-          });
-
-        // Listen on random port
-        server.listen(0);
-        this.logger.debug(logPrefix + 'Selected port for local language server: ' + server.address().port);
-        connMgr.connectionConfiguration.port = server.address().port;
-        server.close();
       }
+      connMgr.startLanguageServerProcess(localServer.command, localServer.args, localServer.options, callback);
     }else{
       this.logger.debug(logPrefix + 'STDIO Server process starting');
       connMgr.startLanguageServerProcess(localServer.command, localServer.args, localServer.options, callback);