Interface Gatherer

prometheus/registry.go:140–161

Gatherer is the interface for the part of a registry in charge of gathering the collected metrics into a number of MetricFamilies. The Gatherer interface comes with the same general implication as described for the Registerer interface.

// comes with the same general implication as described for the Registerer
// interface.
type Gatherer interface {
	// Gather calls the Collect method of the registered Collectors and then
	// gathers the collected metrics into a lexicographically sorted slice
	// of uniquely named MetricFamily protobufs. Gather ensures that the
	// returned slice is valid and self-consistent so that it can be used
	// for valid exposition. As an exception to the strict consistency
	// requirements described for metric.Desc, Gather will tolerate
	// different sets of label names for metrics of the same metric family.
	//
	// Even if an error occurs, Gather attempts to gather as many metrics as
	// possible. Hence, if a non-nil error is returned, the returned
	// MetricFamily slice could be nil (in case of a fatal error that
	// prevented any meaningful metric collection) or contain a number of
	// MetricFamily protobufs, some of which might be incomplete, and some
	// might be missing altogether. The returned error (which might be a
	// MultiError) explains the details. Note that this is mostly useful for
	// debugging purposes. If the gathered protobufs are to be used for
	// exposition in actual monitoring, it is almost always better to not
	// expose an incomplete result and instead disregard the returned
	// MetricFamily protobufs in case the returned error is non-nil.
	Gather() ([]*dto.MetricFamily, error)
}

// Register registers the provided Collector with the DefaultRegisterer.
//