pr fixes - control reporting interval for tests, don't start metrics if app launched standalone, remove socket writer

Author: steveslayden

README.md

@@ -92,16 +92,20 @@ Usage: nodejs-dashboard [options] -- [node] [script] [arguments]
 ```
 Options:
 
-  -h, --help               output usage information
-  -V, --version            output the version number
-  -p, --port [port]        Socket listener port
-  -e, --eventdelay [ms]    Minimum threshold for event loop reporting, default 10ms
-  -s, --scrollback [count] Maximum scroll history for log windows
+  -h, --help                 output usage information
+  -V, --version              output the version number
+  -p, --port [port]          Socket listener port
+  -r, --refreshinterval [ms] Metrics refresh interval, default 1000ms
+  -e, --eventdelay [ms]      Minimum threshold for event loop reporting, default 10ms
+  -s, --scrollback [count]   Maximum scroll history for log windows
 ```
 
 #####`--port`
 Under the hood the dashboard utilizes SocketIO with a default port of `9838`. If this conflicts with an existing service you can optionally change this value.
 
+#####`--refreshinterval`
+Specifies the interval in milliseconds that the metrics should be refreshed. The default is 1000 ms (1 second).
+
 #####`--eventdelay`
 This tunes the minimum threshold for reporting event loop delays. The default value is `10ms`. Any delay below this value will be reported at `0`.
 

bin/nodejs-dashboard.js

@@ -16,6 +16,7 @@ var program = new commander.Command(pkg.name);
 
 program.version(pkg.version);
 program.option("-p, --port [port]", "Socket listener port");
+program.option("-r, --refreshinterval [ms]", "Metrics refresh interval, default 1000ms");
 program.option("-e, --eventdelay [ms]", "Minimum threshold for event loop reporting, default 10ms");
 program.option("-s, --scrollback [count]", "Maximum scroll history for log windows");
 program.usage("[options] -- [node] [script] [arguments]");
@@ -30,10 +31,12 @@ var command = program.args[0];
 var args = program.args.slice(1);
 
 var port = program.port || config.PORT;
+var refreshInterval = program.refreshinterval || config.REFRESH_INTERVAL;
 var eventDelay = program.eventdelay || config.BLOCKED_THRESHOLD;
 var scrollback = program.scrollback || config.SCROLLBACK;
 
 process.env[config.PORT_KEY] = port;
+process.env[config.REFRESH_INTERVAL_KEY] = refreshInterval;
 process.env[config.BLOCKED_THRESHOLD_KEY] = eventDelay;
 
 var child = spawn(command, args, {

lib/config.js

@@ -5,6 +5,8 @@ var pkg = require("../package.json");
 module.exports = {
   PORT: 9838,
   PORT_KEY: pkg.name + "_PORT",
+  REFRESH_INTERVAL: 1000,
+  REFRESH_INTERVAL_KEY: pkg.name + "_REFRESH_INTERVAL",
   BLOCKED_THRESHOLD: 10,
   BLOCKED_THRESHOLD_KEY: pkg.name + "_BLOCKED_THRESHOLD",
   SCROLLBACK: 1000

lib/dashboard-agent.js

@@ -1,6 +1,6 @@
 "use strict";
 
-var socketWriterFactory = require("./socket-writer");
+var SocketIO = require("socket.io-client");
 var blocked = require("blocked");
 var pusage = require("pidusage");
 var os = require("os");
@@ -11,11 +11,15 @@ var dashboardAgent = function () {
 
   var options = {
     port: process.env[config.PORT_KEY],
-    blockedThreshold: process.env[config.BLOCKED_THRESHOLD_KEY],
-    refreshInterval: 1000
+    refreshInterval: process.env[config.REFRESH_INTERVAL_KEY],
+    blockedThreshold: process.env[config.BLOCKED_THRESHOLD_KEY]
   };
 
-  var socketWriter = socketWriterFactory(options);
+  // check if the app was launched w/o the dashboard
+  // if so, don't start any of the monitoring
+  var enabled = options.port && options.refreshInterval && options.blockedThreshold;
+
+  var socket;
 
   var metrics = {
     eventLoop: {
@@ -35,8 +39,6 @@ var dashboardAgent = function () {
     metrics.eventLoop.delay = delay;
   };
 
-  blocked(_delayed, { threshold: options.blockedThreshold });
-
   var _getStats = function (cb) {
     _.merge(metrics.mem, process.memoryUsage());
 
@@ -61,9 +63,11 @@ var dashboardAgent = function () {
     _getStats(function (err, newMetrics) {
       if (err) {
         console.error("Failed to load metrics: ", err); //eslint-disable-line
-        socketWriter.write("error", JSON.stringify(err));
-      } else {
-        socketWriter.write("metrics", JSON.stringify(newMetrics));
+        if (socket && socket.connected) {
+          socket.emit("error", JSON.stringify(err));
+        }
+      } else if (socket && socket.connected) {
+        socket.emit("metrics", JSON.stringify(newMetrics));
       }
 
       resetEventMetrics();
@@ -72,12 +76,22 @@ var dashboardAgent = function () {
   };
 
   var startPump = function () {
-    options.intervalId = setInterval(_emitStats, options.refreshInterval);
+    if (enabled) {
+      socket = new SocketIO("http://localhost:" + options.port);
+      blocked(_delayed, { threshold: options.blockedThreshold });
+      options.intervalId = setInterval(_emitStats, options.refreshInterval);
+    }
   };
 
   var destroy = function () {
-    socketWriter.close();
-    clearInterval(options.intervalId);
+    if (socket) {
+      socket.close();
+      socket = null;
+    }
+    if (options.intervalId) {
+      clearInterval(options.intervalId);
+      options.intervalId = null;
+    }
   };
 
   startPump();

lib/socket-writer.js

@@ -18,6 +18,7 @@ describe("dashboard-agent", function () {
   before(function () {
     process.env[config.PORT_KEY] = TEST_PORT;
     process.env[config.BLOCKED_THRESHOLD_KEY] = 1;
+    process.env[config.REFRESH_INTERVAL_KEY] = 10;
   });
 
   beforeEach(function () {