make Kardia singleton, so that it is accessible from all files in an …

…uniform way

index.js

@@ -1,3 +1,37 @@
 "use strict";
 
-module.exports = require('./lib/kardia');
+var currentStatus = null,
+	cluster = require("cluster"),
+	Status = require(__dirname + "/lib/status.js");
+
+// if running on a cluster worker, we assume the master already has Kardia started, thus we
+// instantiate a wrapper instance right-away
+if (!cluster.isMaster) {
+	currentStatus = new Status({});
+	module.exports = currentStatus;
+} else {
+	var startHandler = function(config) {
+		if (currentStatus === null) {
+			currentStatus = new Status(config);
+
+			if (!currentStatus._instanceId) {
+				currentStatus._instanceId = Date.now()+'.'+Math.round(Math.random()*1000);
+			}
+
+			currentStatus.on("serverStopped", function() {
+				currentStatus = null;
+				module.exports = { start: startHandler };
+			});
+
+			if (cluster.isMaster) {
+				currentStatus.startServer();
+			}
+
+			module.exports = currentStatus;
+		}
+		return currentStatus;
+	}
+
+	// otherwise only expose the .start() command, which in turn returns the currentStatus.
+	module.exports.start = startHandler;
+}

lib/status.js

@@ -4,28 +4,28 @@ var http = require("http"),
 	os = require("os"),
 	cluster = require("cluster"),
 	url = require("url"),
-	Worker = require('./worker.js'),
+	Worker = require(__dirname + "/worker.js"),
 	formatTime = require(__dirname + "/formatTime.js"),
 	formatMemory = require(__dirname + "/formatMemory.js");
 
 function Status(config) {
-	if (!config) {
+	if (cluster.isMaster && !config) {
 		this.log("error", "Kardia cannot start - configuration not supplied");
 		return false;
 	}
-	if (!config.name) {
+	if (cluster.isMaster && !config.name) {
 		this.log("error", "Kardia cannot start - service name must be supplied");
 		return false;
 	}
 
 	this.config = config;
 	config.debug = !!config.debug;
 
-	if (!config.port) {
+	if (cluster.isMaster && !config.port) {
 		this.log("info", "Kardia starting on default port (12900)");
 		config.port = 12900;
 	}
-	if (!config.host) {
+	if (cluster.isMaster && !config.host) {
 		this.log("info", "Kardia starting on default host (0.0.0.0)");
 		config.host = '0.0.0.0';
 	}
@@ -46,7 +46,7 @@ function Status(config) {
 
 	this.measureFallBehind();
 
-	if (config.healthcheck) {
+	if (cluster.isMaster && config.healthcheck) {
 		this.registerHealthcheck(config.healthcheck);
 	}
 
@@ -227,14 +227,20 @@ Status.prototype.getConsulHealthcheck = function(options) {
 	return consulParams;
 };
 
+Status.prototype._onClusterFork = function() {
+	this.addWorker(worker);
+}
+
+Status.prototype._onClusterExit = function() {
+	this.removeWorker(worker.process.pid);
+}
+
 Status.prototype.startServer = function() {
-	cluster.on("fork", (function(worker) {
-		this.addWorker(worker);
-	}).bind(this));
+	this.onClusterFork = this._onClusterFork.bind(this);
+	this.onClusterExit = this._onClusterExit.bind(this);
 
-	cluster.on("exit", (function(worker) {
-		this.removeWorker(worker.process.pid);
-	}).bind(this));
+	cluster.on("fork", this.onClusterFork);
+	cluster.on("exit", this.onClusterExit);
 
 	this.server = http.createServer((function (req, res) {
 		this.emit('serverRequest', { req: req });
@@ -318,7 +324,13 @@ Status.prototype.stopServer = function() {
 	if (!cluster.isMaster) {
 		return false;
 	}
-	this.server.close();
+
+	try {
+		this.server.close();
+		cluster.removeListener("fork", this.onClusterFork);
+		cluster.removeListener("exit", this.onClusterExit);
+	} catch (e) {}
+
 	this.emit("serverStopped");
 
 	return true;
@@ -406,4 +418,8 @@ Status.prototype.removeListener = function(eventName, handler) {
 	return true;
 };
 
+Status.prototype.start = function() {
+	// dummy wrapper for catching subsequent start calls made by the underlying service using Kardia.
+}
+
 module.exports = Status;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "kardia",
-  "version": "0.4.2",
+  "version": "0.5.0",
   "description": "A humane process status API module to expose any operational/internal indicators of any Node.js process for status aggregation and monitoring. JSON format over HTTP protocol.",
   "main": "index.js",
   "scripts": {

test/tests/test_that_name_must_be_supplied.js

@@ -3,6 +3,7 @@ var fail = require(__dirname + "/../lib/fail.js");
 module.exports = function(next) {
 	var errStr = "Kardia cannot start - service name must be supplied";
 	console.log("Expecting "+errStr);
+
 	try {
 		var Kardia = require("../..");
 		Kardia.start({});