prom::MetricBase< Derived > Class Template Reference

CRTP base shared by every metric type. More...

#include <metric_base.hpp>

Collaboration diagram for prom::MetricBase< Derived >:

Classes
struct	Binding
	A resolved (adapter, handle) snapshot — the result of bind(). More...

Public Member Functions
std::string_view	name () const noexcept
	The metric's fully-qualified name.
MetricType	type () const noexcept
	The metric kind.

Protected Member Functions
	MetricBase (const MetricType type, const std::string_view name, const std::string_view help)
	Standalone, unbound construction from a name and help string.
	MetricBase (std::shared_ptr< MetricCore > core)
	Adopt an already-populated core (registered metrics and children).
	MetricBase (const MetricBase &)=default
MetricBase &	operator= (const MetricBase &)=default
	MetricBase (MetricBase &&)=default
MetricBase &	operator= (MetricBase &&)=default
	~MetricBase ()=default
Binding	bind () const noexcept
	Resolve the adapter and backend handle this metric should record against.
const std::shared_ptr< MetricCore > &	core () const noexcept
Derived	make_child (const Labels &dynamic) const noexcept
	Resolve a labeled child of the same metric type.
bool	reconcile_unit (const Unit &observed, Adapter &adapter) const noexcept
	Reconcile an observed unit against the family's known unit.
bool	check_finite (const double value, std::string_view op) const noexcept
	Drop-and-log guard for a non-finite sample.

Static Protected Member Functions
static spdlog::logger *	logger () noexcept
	The shared per-process metrics logger.

Protected Attributes
std::shared_ptr< MetricCore >	core_

Detailed Description

template<class Derived>
class prom::MetricBase< Derived >

CRTP base shared by every metric type.

Provides the binding machinery and the protected helpers (record_*, make_child, reconcile_unit) the concrete types build their public surface from.

Constructor & Destructor Documentation

MetricBase() [1/4]

template<class Derived >

prom::MetricBase< Derived >::MetricBase ( const MetricType  type, const std::string_view  name, const std::string_view  help  )

inlineprotected

Standalone, unbound construction from a name and help string.

Reads its adapter from the process-wide cell and binds lazily on first use. It also follows the process-wide global decoration, so a prefix / labels installed via Registry::global() reach standalone metrics too; with the default (empty) decoration the effective name and labels are unchanged.

MetricBase() [2/4]

template<class Derived >

prom::MetricBase< Derived >::MetricBase ( std::shared_ptr< MetricCore >  core )

inlineexplicitprotected

Adopt an already-populated core (registered metrics and children).

MetricBase() [3/4]

template<class Derived >

prom::MetricBase< Derived >::MetricBase ( const MetricBase< Derived > &  )

protecteddefault

MetricBase() [4/4]

template<class Derived >

prom::MetricBase< Derived >::MetricBase ( MetricBase< Derived > &&  )

protecteddefault

~MetricBase()

template<class Derived >

prom::MetricBase< Derived >::~MetricBase ( )

protecteddefault

Member Function Documentation

bind()

template<class Derived >

Binding prom::MetricBase< Derived >::bind ( ) const

inlineprotectednoexcept

Resolve the adapter and backend handle this metric should record against.

Fast path: load the published binding. A pinned binding (a labeled child) is returned as-is — children never migrate. Otherwise the binding is reused while it matches the source's adapter version() and, for a scoped metric, the scope's config version().

Slow path (rebind): resolve the current adapter from the source, recompute the name / labels / display from the live scope (if scoped), register the family, and publish a fresh binding. This fires on first use of a standalone/scoped metric, on an adapter swap (live migration to the new backend — the previous backend's series are left behind), and on a scope reconfiguration.

check_finite()

template<class Derived >

bool prom::MetricBase< Derived >::check_finite ( const double  value, std::string_view  op  ) const

inlineprotectednoexcept

Drop-and-log guard for a non-finite sample.

Returns true when the value is safe to record.

core()

template<class Derived >

const std::shared_ptr< MetricCore > & prom::MetricBase< Derived >::core ( ) const

inlineprotectednoexcept

logger()

template<class Derived >

static spdlog::logger * prom::MetricBase< Derived >::logger ( )

inlinestaticprotectednoexcept

The shared per-process metrics logger.

make_child()

template<class Derived >

Derived prom::MetricBase< Derived >::make_child ( const Labels &  dynamic ) const

inlineprotectednoexcept

Resolve a labeled child of the same metric type.

The child carries the backend's resolved child handle and points back at this family for unit reconciliation. The child is pinned: it snapshots the adapter and the scope-decorated state in effect at the time of the labels() call and never migrates, even if the source adapter or scope later changes.

name()

template<class Derived >

std::string_view prom::MetricBase< Derived >::name ( ) const

inlinenoexcept

The metric's fully-qualified name.

operator=() [1/2]

template<class Derived >

MetricBase & prom::MetricBase< Derived >::operator= ( const MetricBase< Derived > &  )

protecteddefault

operator=() [2/2]

template<class Derived >

MetricBase & prom::MetricBase< Derived >::operator= ( MetricBase< Derived > &&  )

protecteddefault

reconcile_unit()

template<class Derived >

bool prom::MetricBase< Derived >::reconcile_unit ( const Unit &  observed, Adapter &  adapter  ) const

inlineprotectednoexcept

Reconcile an observed unit against the family's known unit.

Returns false (and logs) when a dimensional sample's kind contradicts the latched kind, signalling the caller to drop the sample. A unitless sample always passes. The first dimensional sample latches the unit.

type()

template<class Derived >

MetricType prom::MetricBase< Derived >::type ( ) const

inlinenoexcept

The metric kind.

Member Data Documentation

core_

template<class Derived >

std::shared_ptr<MetricCore> prom::MetricBase< Derived >::core_

protected

---

The documentation for this class was generated from the following files:

• include/prom/fwd.hpp
• include/prom/metric_base.hpp