overleaf/services/real-time/app/coffee/HealthCheckManager.js

85 lines
2.8 KiB
JavaScript

/* eslint-disable
no-return-assign,
no-unused-vars,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
* decaffeinate suggestions:
* DS102: Remove unnecessary code created because of implicit returns
* DS207: Consider shorter variations of null checks
* Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
*/
let HealthCheckManager;
const metrics = require("metrics-sharelatex");
const logger = require("logger-sharelatex");
const os = require("os");
const HOST = os.hostname();
const PID = process.pid;
let COUNT = 0;
const CHANNEL_MANAGER = {}; // hash of event checkers by channel name
const CHANNEL_ERROR = {}; // error status by channel name
module.exports = (HealthCheckManager = class HealthCheckManager {
// create an instance of this class which checks that an event with a unique
// id is received only once within a timeout
constructor(channel, timeout) {
// unique event string
this.channel = channel;
if (timeout == null) { timeout = 1000; }
this.id = `host=${HOST}:pid=${PID}:count=${COUNT++}`;
// count of number of times the event is received
this.count = 0;
// after a timeout check the status of the count
this.handler = setTimeout(() => {
return this.setStatus();
}
, timeout);
// use a timer to record the latency of the channel
this.timer = new metrics.Timer(`event.${this.channel}.latency`);
// keep a record of these objects to dispatch on
CHANNEL_MANAGER[this.channel] = this;
}
processEvent(id) {
// if this is our event record it
if (id === this.id) {
this.count++;
if (this.timer != null) {
this.timer.done();
}
return this.timer = null; // only time the latency of the first event
}
}
setStatus() {
// if we saw the event anything other than a single time that is an error
if (this.count !== 1) {
logger.err({channel:this.channel, count:this.count, id:this.id}, "redis channel health check error");
}
const error = (this.count !== 1);
return CHANNEL_ERROR[this.channel] = error;
}
// class methods
static check(channel, id) {
// dispatch event to manager for channel
return (CHANNEL_MANAGER[channel] != null ? CHANNEL_MANAGER[channel].processEvent(id) : undefined);
}
static status() {
// return status of all channels for logging
return CHANNEL_ERROR;
}
static isFailing() {
// check if any channel status is bad
for (const channel in CHANNEL_ERROR) {
const error = CHANNEL_ERROR[channel];
if (error === true) { return true; }
}
return false;
}
});