overleaf/libraries/metrics/prom_wrapper.js
2020-07-17 16:01:58 +01:00

148 lines
3.4 KiB
JavaScript

/*
* decaffeinate suggestions:
* DS101: Remove unnecessary use of Array.from
* DS102: Remove unnecessary code created because of implicit returns
* DS205: Consider reworking code to avoid use of IIFEs
* Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
*/
const prom = require('prom-client');
const registry = require('prom-client').register;
const metrics = new Map();
const optsKey = function(opts) {
let keys = Object.keys(opts);
if (keys.length === 0) { return ''; }
keys = keys.sort();
let hash = '';
for (let key of Array.from(keys)) {
if (hash.length) { hash += ","; }
hash += `${key}:${opts[key]}`;
}
return hash;
};
const extendOpts = function(opts, labelNames) {
for (let label of Array.from(labelNames)) {
if (!opts[label]) { opts[label] = ''; }
}
return opts;
};
const optsAsArgs = function(opts, labelNames) {
const args = [];
for (let label of Array.from(labelNames)) {
args.push(opts[label] || '');
}
return args;
};
const PromWrapper = {
ttlInMinutes: 0,
registry,
metric(type, name) {
return metrics.get(name) || new MetricWrapper(type, name);
},
collectDefaultMetrics: prom.collectDefaultMetrics
};
class MetricWrapper {
constructor(type, name) {
metrics.set(name, this);
this.name = name;
this.instances = new Map();
this.lastAccess = new Date();
this.metric = (() => { switch (type) {
case "counter":
return new prom.Counter({
name,
help: name,
labelNames: ['app','host','status','method', 'path']
});
case "summary":
return new prom.Summary({
name,
help: name,
maxAgeSeconds: 60,
ageBuckets: 10,
labelNames: ['app', 'host', 'path', 'status_code', 'method', 'collection', 'query']
});
case "gauge":
return new prom.Gauge({
name,
help: name,
labelNames: ['app','host', 'status']
});
} })();
}
inc(opts, value) {
return this._execMethod('inc', opts, value);
}
observe(opts, value) {
return this._execMethod('observe', opts, value);
}
set(opts, value) {
return this._execMethod('set', opts, value);
}
sweep() {
const thresh = new Date(Date.now() - (1000 * 60 * PromWrapper.ttlInMinutes));
this.instances.forEach((instance, key) => {
if (thresh > instance.time) {
if (process.env['DEBUG_METRICS']) {
console.log("Sweeping stale metric instance", this.name, {opts: instance.opts}, key);
}
return this.metric.remove(...Array.from(optsAsArgs(instance.opts, this.metric.labelNames) || []));
}
});
if (thresh > this.lastAccess) {
if (process.env['DEBUG_METRICS']) {
console.log("Sweeping stale metric", this.name, thresh, this.lastAccess);
}
metrics.delete(this.name);
return registry.removeSingleMetric(this.name);
}
}
_execMethod(method, opts, value) {
opts = extendOpts(opts, this.metric.labelNames);
const key = optsKey(opts);
if (key !== '') { this.instances.set(key, { time: new Date(), opts }); }
this.lastAccess = new Date();
return this.metric[method](opts, value);
}
}
if (!PromWrapper.sweepRegistered) {
if (process.env['DEBUG_METRICS']) {
console.log("Registering sweep method");
}
PromWrapper.sweepRegistered = true;
setInterval(
function() {
if (PromWrapper.ttlInMinutes) {
if (process.env['DEBUG_METRICS']) {
console.log("Sweeping metrics");
}
return metrics.forEach((metric, key) => {
return metric.sweep();
});
}
},
60000);
}
module.exports = PromWrapper;