index.js
3.88 KB
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(function () {
'use strict';
const fs = require('fs');
const path = require('path');
const os = require('os');
const onHeaders = require('on-headers');
const pidusage = require('pidusage');
let io;
const defaultConfig = {
title: 'Express Status',
path: '/status',
spans: [{
interval: 1,
retention: 60
}, {
interval: 5,
retention: 60
}, {
interval: 15,
retention: 60
}]
};
Array.prototype.last = function() {
return this[this.length - 1];
};
const gatherOsMetrics = (io, span) => {
const defaultResponse = {
'2': 0,
'3': 0,
'4': 0,
'5': 0,
count: 0,
mean: 0,
timestamp: Date.now()
};
pidusage.stat(process.pid, (err, stat) => {
// Convert from B to MB
stat.memory = stat.memory / 1024 / 1024;
stat.load = os.loadavg();
stat.timestamp = Date.now();
span.os.push(stat);
if (!span.responses[0] || span.responses.last().timestamp + (span.interval * 1000) < Date.now()) span.responses.push(defaultResponse);
if (span.os.length >= span.retention) span.os.shift();
if (span.responses[0] && span.responses.length > span.retention) span.responses.shift();
sendMetrics(io, span);
});
};
const sendMetrics = (io, span) => {
io.emit('stats', {
os: span.os[span.os.length - 2],
responses: span.responses[span.responses.length - 2],
interval: span.interval,
retention: span.retention
});
};
const middlewareWrapper = (config) => {
if (config === null || config === undefined) {
config = defaultConfig;
}
if (config.path === undefined || !config instanceof String) {
config.path = defaultConfig.path;
}
if (config.spans === undefined || !config instanceof Array) {
config.spans = defaultConfig.spans;
}
return (req, res, next) => {
if (io === null || io === undefined) {
io = require('socket.io')(req.socket.server);
io.on('connection', (socket) => {
socket.emit('start', config.spans);
socket.on('change', function() { socket.emit('start', config.spans); });
});
config.spans.forEach((span) => {
span.os = [];
span.responses = [];
setInterval(() => gatherOsMetrics(io, span), span.interval * 1000);
});
}
const startTime = process.hrtime();
if (req.path === config.path) {
fs.readFile(path.join(__dirname + '/index.html'), function(err, content) {
content = content.toString().replace(new RegExp(defaultConfig.title, 'g'), config.title);
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(content);
res.end();
});
} else {
onHeaders(res, () => {
const diff = process.hrtime(startTime);
const responseTime = diff[0] * 1e3 + diff[1] * 1e-6;
const category = Math.floor(res.statusCode / 100);
config.spans.forEach((span) => {
const last = span.responses[span.responses.length - 1];
if (last !== undefined &&
span.responses.last().timestamp / 1000 + span.interval > Date.now() / 1000) {
span.responses.last()[category]++;
span.responses.last().count++;
span.responses.last().mean = span.responses.last().mean + ((responseTime - span.responses.last().mean) / span.responses.last().count);
} else {
span.responses.push({
'2': category === 2 ? 1 : 0,
'3': category === 3 ? 1 : 0,
'4': category === 4 ? 1 : 0,
'5': category === 5 ? 1 : 0,
count: 1,
mean: responseTime,
timestamp: Date.now()
});
}
});
});
next();
}
};
};
module.exports = middlewareWrapper;
}());