예제 #1
0
// Save metric and index into db.
func (d *Detector) save(m *models.Metric, idx *models.Index) error {
	// Save index.
	if err := d.db.Index.Put(idx); err != nil {
		return err
	}
	// Save metric.
	m.LinkTo(idx) // Important
	if err := d.db.Metric.Put(m); err != nil {
		return err
	}
	return nil
}
예제 #2
0
// analyze given metric with 3sigma, returns the new index.
// Steps:
//	1. Get index.
//	2. Get history values.
//	3. Do 3sigma calculation.
//	4. Move the index next.
func (d *Detector) analyze(idx *models.Index, m *models.Metric, rules []*models.Rule) *models.Index {
	fz := idx != nil && d.shouldFill0(m, rules)
	if idx != nil {
		m.LinkTo(idx)
	}
	vals, err := d.values(m, fz)
	if err != nil {
		return nil
	}
	d.div3Sigma(m, vals)
	return d.nextIdx(idx, m, d.pickTrendingFactor(rules))
}
예제 #3
0
// div3Sigma sets given metric score and average via 3-sigma.
//	states that nearly all values (99.7%) lie within the 3 standard deviations
//	of the mean in a normal distribution.
func (d *Detector) div3Sigma(m *models.Metric, vals []float64) {
	if len(vals) == 0 {
		m.Score = 0
		m.Average = m.Value
		return
	}
	// Values average and standard deviation.
	avg := mathutil.Average(vals)
	std := mathutil.StdDev(vals, avg)
	// Set metric average
	m.Average = avg
	// Set metric score
	if len(vals) <= int(d.cfg.Detector.LeastCount) { // Number of values not enough
		m.Score = 0
		return
	}
	last := m.Value
	if std == 0 { // Eadger
		switch {
		case last == avg:
			m.Score = 0
		case last > avg:
			m.Score = 1
		case last < avg:
			m.Score = -1
		}
		return
	}
	m.Score = (last - avg) / (3 * std) // 3-sigma
}
예제 #4
0
파일: detector.go 프로젝트: hit9/banshee
// Test metric and index with rules.
// The following function will fill the m.TestedRules.
func (d *Detector) test(m *models.Metric, idx *models.Index, rules []*models.Rule) {
	for _, rule := range rules {
		if rule.Test(m, idx, d.cfg) {
			// Add tested ok rules.
			m.TestedRules = append(m.TestedRules, rule)
		}
	}
}
예제 #5
0
// decodeKey decodes db key into metric, this will fill metric name and metric
// stamp.
func decodeKey(key []byte, m *models.Metric) error {
	s := string(key)
	if len(s) <= stampLen {
		return ErrCorrupted
	}
	// First substring is Name.
	idx := len(s) - stampLen
	m.Name = s[:idx]
	// Last substring is Stamp.
	str := s[idx:]
	n, err := strconv.ParseUint(str, convBase, 32)
	if err != nil {
		return err
	}
	m.Stamp = horizon + uint32(n)
	return nil
}