use npid for pid file support

defaults/config.js

@@ -34,6 +34,19 @@ module.exports = {
 	//
 	bind: undefined,
 
+	//
+	// Enable or disable pid file creation
+	//
+	// string values specify the file path to use
+	// boolean values result in the default file path being used
+	//
+	// paths are relative to the 'HOME' folder
+	//
+	// @type     string | boolean
+	// @default  true
+	//
+	pidFile: true,
+
 	//
 	// Set the default theme.
 	//

package.json

@@ -35,6 +35,7 @@
     "lodash": "~2.4.1",
     "mkdirp": "^0.5.0",
     "moment": "~2.7.0",
+    "npid": "^0.4.0",
     "read": "^1.0.5",
     "request": "^2.51.0",
     "slate-irc": "~0.7.3",

src/command-line/start.js

@@ -2,19 +2,59 @@ var ClientManager = new require("../clientManager");
 var program = require("commander");
 var shout = require("../server");
 var Helper = require("../helper");
+var path = require("path");
 
 program
 	.option("-H, --host <ip>"   , "host")
 	.option("-P, --port <port>" , "port")
 	.option("-B, --bind <ip>"   , "bind")
 	.option("    --public"      , "mode")
 	.option("    --private"     , "mode")
+	.option("    --silent"      , "suppress errors about pid file creation")
 	.command("start")
 	.description("Start the server")
 	.action(function() {
 		var users = new ClientManager().getUsers();
 		var config = Helper.getConfig();
 		var mode = config.public;
+
+		if (config.pidFile) {
+			// setup exception handler to cleanup pid file and log errors
+			process.on("uncaughtException", function(e) {
+				console.log("uncaughtException: " + e.stack || e);
+				process.exit(1);
+			});
+
+			// setup signal handlers to cleanly exit process
+			// which allows the pid file to be removed
+			process.on("SIGINT", process.exit.bind(process, 0));
+			process.on("SIGTERM", process.exit.bind(process, 0));
+
+			// use the default pid file name if the configuration
+			// variable is not a string
+			if (typeof config.pidFile !== "string") {
+				config.pidFile = "shout.pid";
+			}
+
+			// get the absolute path of the pid file to use
+			var pidFilePath = path.resolve(Helper.HOME, config.pidFile);
+
+			// attempt to create the pid file or die trying
+			try {
+				var pid = require("npid").create(pidFilePath);
+				pid.removeOnExit();
+			} catch (e) {
+				// spit out an error message about pid file creation
+				if (!program.silent) {
+					console.log("unable to create pid file: " + pidFilePath);
+					console.log(e.stack || e);
+				}
+
+				// process is already running, so bail out now
+				process.exit(1);
+			}
+		}
+
 		if (program.public) {
 			mode = true;
 		} else if (program.private) {