precis-error/lib/handler.js

Error endpoint monitor for Precis UI.

const DEFAULT_THRESHOLD = 40;
const DEFAULT_RETAIN_COUNT = 100;
const TIME_TO_BUCKET = 1000 * 60 * 15;
var noop = function(){};

var Handler = function(options){
  this.threshold = options.threshold || DEFAULT_THRESHOLD;
  this.retain = options.retainCount || DEFAULT_RETAIN_COUNT;
  this.event = options.event;
  this.statsEvent = options.statsEvent;
  this.sockets = options.sockets;
  this.logger = options.logger;
  this.store = options.store;
  this.records = [];
  this.buckets = [];
};

Handler.prototype.getBucket = function(time){
  var i = this.buckets.length-1;
  var bkt = new Date(Date.parse(time));
  bkt.setMilliseconds(0);
  bkt.setSeconds(Math.floor(bkt.getSeconds()/15)*15);
  var tim = bkt.getTime();
  var key = 'error_'+tim;
  this.checkTrimBuckets(tim);
  while(i>-1){
    if(this.buckets[i] && (this.buckets[i].key===key)){
      return this.buckets[i];
    }
    i--;
  }
  var bucket = {
    key: key,
    time: bkt,
    stamp: tim,
    stats: {
      error: 0
    }
  };
  this.buckets.push(bucket);
  return bucket;
};

Handler.prototype.checkTrimBuckets = function(time){
  var eol = (time || ((new Date()).getTime()))-(TIME_TO_BUCKET);
  this.buckets = this.buckets.filter((bucket)=>bucket && (bucket.stamp >= eol));
  /*
  while(this.buckets && this.buckets.length && (this.buckets[0].stamp<eol)){
    this.buckets.shift();
  }
  //*/
};

Handler.prototype.enqueueStatsUpdate = function(bucket){
  var tmr = bucket.enqueueTimer;
  if(!tmr){
    bucket.enqueueTimer = setTimeout(function(){
      bucket.enqueueTimer = false;
      this.sockets.emit(this.statsEvent, {
        _id: bucket.key,
        key: bucket.key,
        time: bucket.time,
        stamp: bucket.stamp,
        stats: {
          error: bucket.stats.error
        }
      });
    }.bind(this), 1000);
  }
};

Handler.prototype.enqueueErrorRecord = function(record){
  var tmr = this._errorRecordTimer;
  if(!tmr){
    this._errorRecords = [record];
    return this._errorRecordTimer = setTimeout(function(){
      this.sockets.emit(this.event, this._errorRecords);
      this._errorRecordTimer = false;
    }.bind(this));
  }
  this._errorRecords.push(record);
};

var getValue = function(from, key, def){
  var o = from;
  var path = key.split('.');
  var segment;
  while(o && path.length){
    segment = path.shift();
    o = o[segment];
  }
  if(o){
    return o;
  }
  return def;
};

Handler.prototype.push = function(data){
  if(data.level < this.threshold){
    return;
  }
  if(getValue(data, 'data.0.data.code')==='ECONNRESET'){
    return;
  }
  var bucket = this.getBucket(data.time||data.dateTime);
  bucket.stats.error++;
  this.records.push(data);
  //this.sockets.emit(this.event, data);
  this.enqueueErrorRecord(data);
  this.store.insert(data, noop);
  if(this.records.length>this.retain){
    this.records = this.records.slice(this.records.length-this.retain);
  }
  this.enqueueStatsUpdate(bucket);
};

module.exports = {Handler};