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 |