Golang Timestamp.Sub方法代码示例

// eval evaluates the rule expression and then creates pending alerts and fires
// or removes previously pending alerts accordingly.
func (rule *AlertingRule) eval(timestamp clientmodel.Timestamp, engine *promql.Engine) (promql.Vector, error) {
	query, err := engine.NewInstantQuery(rule.vector.String(), timestamp)
	if err != nil {
		return nil, err
	}
	exprResult, err := query.Exec().Vector()
	if err != nil {
		return nil, err
	}

	rule.mutex.Lock()
	defer rule.mutex.Unlock()

	// Create pending alerts for any new vector elements in the alert expression
	// or update the expression value for existing elements.
	resultFPs := map[clientmodel.Fingerprint]struct{}{}
	for _, sample := range exprResult {
		fp := sample.Metric.Metric.Fingerprint()
		resultFPs[fp] = struct{}{}

		if alert, ok := rule.activeAlerts[fp]; !ok {
			labels := clientmodel.LabelSet{}
			labels.MergeFromMetric(sample.Metric.Metric)
			labels = labels.Merge(rule.labels)
			if _, ok := labels[clientmodel.MetricNameLabel]; ok {
				delete(labels, clientmodel.MetricNameLabel)
			}
			rule.activeAlerts[fp] = &Alert{
				Name:        rule.name,
				Labels:      labels,
				State:       StatePending,
				ActiveSince: timestamp,
				Value:       sample.Value,
			}
		} else {
			alert.Value = sample.Value
		}
	}

	vector := promql.Vector{}

	// Check if any pending alerts should be removed or fire now. Write out alert timeseries.
	for fp, activeAlert := range rule.activeAlerts {
		if _, ok := resultFPs[fp]; !ok {
			vector = append(vector, activeAlert.sample(timestamp, 0))
			delete(rule.activeAlerts, fp)
			continue
		}

		if activeAlert.State == StatePending && timestamp.Sub(activeAlert.ActiveSince) >= rule.holdDuration {
			vector = append(vector, activeAlert.sample(timestamp, 0))
			activeAlert.State = StateFiring
		}

		vector = append(vector, activeAlert.sample(timestamp, 1))
	}

	return vector, nil
}

func (rule *AlertingRule) Eval(timestamp clientmodel.Timestamp, storage metric.PreloadingPersistence) (ast.Vector, error) {
	// Get the raw value of the rule expression.
	exprResult, err := rule.EvalRaw(timestamp, storage)
	if err != nil {
		return nil, err
	}

	rule.mutex.Lock()
	defer rule.mutex.Unlock()

	// Create pending alerts for any new vector elements in the alert expression
	// or update the expression value for existing elements.
	resultFingerprints := utility.Set{}
	for _, sample := range exprResult {
		fp := new(clientmodel.Fingerprint)
		fp.LoadFromMetric(sample.Metric)
		resultFingerprints.Add(*fp)

		if alert, ok := rule.activeAlerts[*fp]; !ok {
			labels := clientmodel.LabelSet{}
			labels.MergeFromMetric(sample.Metric)
			labels = labels.Merge(rule.Labels)
			if _, ok := labels[clientmodel.MetricNameLabel]; ok {
				delete(labels, clientmodel.MetricNameLabel)
			}
			rule.activeAlerts[*fp] = &Alert{
				Name:        rule.name,
				Labels:      labels,
				State:       PENDING,
				ActiveSince: timestamp,
				Value:       sample.Value,
			}
		} else {
			alert.Value = sample.Value
		}
	}

	vector := ast.Vector{}

	// Check if any pending alerts should be removed or fire now. Write out alert timeseries.
	for fp, activeAlert := range rule.activeAlerts {
		if !resultFingerprints.Has(fp) {
			vector = append(vector, activeAlert.sample(timestamp, 0))
			delete(rule.activeAlerts, fp)
			continue
		}

		if activeAlert.State == PENDING && timestamp.Sub(activeAlert.ActiveSince) >= rule.holdDuration {
			vector = append(vector, activeAlert.sample(timestamp, 0))
			activeAlert.State = FIRING
		}

		vector = append(vector, activeAlert.sample(timestamp, 1))
	}

	return vector, nil
}

// interpolateSamples interpolates a value at a target time between two
// provided sample pairs.
func interpolateSamples(first, second *metric.SamplePair, timestamp clientmodel.Timestamp) *metric.SamplePair {
	dv := second.Value - first.Value
	dt := second.Timestamp.Sub(first.Timestamp)

	dDt := dv / clientmodel.SampleValue(dt)
	offset := clientmodel.SampleValue(timestamp.Sub(first.Timestamp))

	return &metric.SamplePair{
		Value:     first.Value + (offset * dDt),
		Timestamp: timestamp,
	}
}