feat(shutdown): do not error if you try to shutdown a server which is…

… already off (#162)

When scripting, you might want to defensively run a `shutdown` command.  If the shutdown fails because the server is already off, you don't care.  If it fails for another reason, you do care.
So I made trying to shutdown a server which is already off just a warning.  I added a flag in case you want the old behavior though.

lib/cmds/opts.ts

@@ -36,6 +36,7 @@ export const SIGNAL_VIA_IPC = 'signal-via-ipc';
 export const DETACH = 'detach';
 export const QUIET = 'quiet';
 export const VERBOSE = 'verbose';
+export const ALREADY_OFF_ERROR = 'already-off-error';
 
 /**
  * The options used by the commands.
@@ -112,5 +113,9 @@ opts[DETACH] = new Option(
     'boolean', false);
 opts[VERBOSE] = new Option(VERBOSE, 'Extra console output', 'boolean', false);
 opts[QUIET] = new Option(QUIET, 'Minimal console output', 'boolean', false);
+opts[ALREADY_OFF_ERROR] = new Option(
+    ALREADY_OFF_ERROR,
+    'Normally if you try to shut down a selenium which is not running, you will get a warning.  This turns it into an error',
+    'boolean', false);
 
 export var Opts = opts;

lib/cmds/shutdown.ts

@@ -11,7 +11,8 @@ let logger = new Logger('shutdown');
 let prog = new Program()
                .command('shutdown', 'shut down the selenium server')
                .action(shutdown)
-               .addOption(Opts[Opt.SELENIUM_PORT]);
+               .addOption(Opts[Opt.SELENIUM_PORT])
+               .addOption(Opts[Opt.ALREADY_OFF_ERROR]);
 
 export var program = prog;
 
@@ -30,6 +31,18 @@ if (argv._[0] === 'shutdown-run') {
 function shutdown(options: Options) {
   logger.info('Attempting to shut down selenium nicely');
   http.get(
-      'http://localhost:' + options[Opt.SELENIUM_PORT].getString() +
-      '/selenium-server/driver/?cmd=shutDownSeleniumServer');
+          'http://localhost:' + options[Opt.SELENIUM_PORT].getString() +
+          '/selenium-server/driver/?cmd=shutDownSeleniumServer')
+      .on('error', (e: NodeJS.ErrnoException) => {
+        if ((e.code == 'ECONNREFUSED') && (e.syscall == 'connect')) {
+          if (!options[Opt.ALREADY_OFF_ERROR].getBoolean()) {
+            logger.warn('Server does not appear to be on');
+          } else {
+            logger.error('Server unreachable, probably not running');
+            throw e;
+          }
+        } else {
+          throw e;
+        }
+      });
 }