CartoDB-SQL-API/lib/services/throttler-stream.js
2019-11-19 16:45:52 +01:00

51 lines
1.5 KiB
JavaScript

'use strict';
const { Transform } = require('stream');
module.exports = class Throttler extends Transform {
constructor (pgstream, ...args) {
super(...args);
this.pgstream = pgstream;
this.sampleLength = global.settings.copy_from_maximum_slow_input_speed_interval || 15;
this.minimunBytesPerSecondThershold = global.settings.copy_from_minimum_input_speed || 0;
this.byteCount = 0;
this.bytesPerSecondHistory = [];
this._interval = setInterval(this._updateMetrics.bind(this), 1000);
}
_updateMetrics () {
this.bytesPerSecondHistory.push(this.byteCount);
this.byteCount = 0;
if (this.bytesPerSecondHistory.length > this.sampleLength) {
this.bytesPerSecondHistory.shift();
}
const doesNotReachThreshold = [];
for (const bytesPerSecond of this.bytesPerSecondHistory) {
if (bytesPerSecond <= this.minimunBytesPerSecondThershold) {
doesNotReachThreshold.push(true);
}
}
if (doesNotReachThreshold.length >= this.sampleLength) {
clearInterval(this._interval);
this.pgstream.emit('error', new Error('Connection closed by server: input data too slow'));
}
}
_transform (chunk, encoding, callback) {
this.byteCount += chunk.length;
callback(null, chunk);
}
_flush (callback) {
clearInterval(this._interval);
callback();
}
};