Method checkWriteRequest

storage/diskmetricstore.go:349–396

checkWriteRequest return if applying the provided WriteRequest will result in a consistent state of metrics. The dms is not modified by the check. However, the WriteRequest _will_ be sanitized: the MetricFamilies are ensured to contain the grouping Labels after the check. If false is returned, the c

(wr WriteRequest)

// consistency check is skipped. The WriteRequest is still sanitized, and the
// presence of timestamps still results in returning false.
func (dms *DiskMetricStore) checkWriteRequest(wr WriteRequest) bool {
	if wr.MetricFamilies == nil {
		// Delete request cannot create inconsistencies, and nothing has
		// to be sanitized.
		return true
	}

	var err error
	defer func() {
		if err != nil && wr.Done != nil {
			wr.Done <- err
		}
	}()

	if timestampsPresent(wr.MetricFamilies) {
		err = errTimestamp
		return false
	}
	for _, mf := range wr.MetricFamilies {
		sanitizeLabels(mf, wr.Labels)
	}

	// Without Done channel, don't do the expensive consistency check.
	if wr.Done == nil {
		return true
	}

	// Construct a test dms, acting on a copy of the metrics, to test the
	// WriteRequest with.
	tdms := &DiskMetricStore{
		metricGroups:   dms.GetMetricFamiliesMap(),
		predefinedHelp: dms.predefinedHelp,
		logger:         promslog.NewNopLogger(),
	}
	tdms.processWriteRequest(wr)

	// Construct a test Gatherer to check if consistent gathering is possible.
	tg := prometheus.Gatherers{
		prometheus.DefaultGatherer,
		prometheus.GathererFunc(func() ([]*dto.MetricFamily, error) {
			return tdms.GetMetricFamilies(), nil
		}),
	}
	if _, err = tg.Gather(); err != nil {
		return false
	}
	return true
}

func (dms *DiskMetricStore) persist() error {
	// Check (again) if persistence is configured because some code paths