stats-beat

Node.js performance statistics emitter

Install

npm install --save stats-beat

Note: requires node v4 or higher.

Usage

const statsBeat = require('stats-beat')();
 
var app = express();
//...
var server = app.listen(PORT);
statsBeat.start({ server });

export STATS_BEAT=all
npm start

Then all performance metrics will be prtinted on the console each 5 seconds

{"sysload%":18,"freememMB":3661,"cpu%":112,"rssMB":152,"heapMB":64,"rps":3149,"resTime_ms":20.887753158529616,"reqBytes":116,"resBytes":114849,"rxKBs":365,"txKBs":361653,"numconn":80,"evloop_us":6646}

To report only CPU and memory ech 2s, use this command:

export STATS_BEAT='period=2&cpu&rss'
npm start

You can register a listener to process the performance metrics in a custom way, e.g. write them in a csv file or send them to a central service.

const statsBeat = require('stats-beat')();
 
var app = express();
//...
var server = app.listen(PORT);
statsBeat.start({ server });
statsBeat.on('stats', (stats) => {
  // process stats
});

Reference

Stats

Selector	Property	Description
sysload	sysload%	1 minute system load average as %. See os.loadavg()
freemem	frememMB	Free system memory in MB. See os.freemem()
cpu	cpu%	Process CPU usage as % of one logical core. Requires node v6.1. See process.cpuUsage()
rss	rssMB	Process memory (resident set size) in MB. See process.memoryUsage()
heap	heapMB	V8 heap used. See process.memoryUsage()
rps	rps	Completed requests per second.
restime	resTime_ms	Response time in ms.
reqbytes	reqBytes	Total request size in bytes.
resbytes	resBytes	Total response size in bytes.
rxrate	rxKBs	KB received per second
txrate	txKBs	KB sent per second
numconn	numconn	Number of concurrent connections on the server. See server.getConnections()
evloop	evloop_us	Node event loop latency in microseconds