prom::CompositeAdapter Class Reference

A backend that forwards every call to a fixed set of child adapters. More...

#include <composite_adapter.hpp>

Inheritance diagram for prom::CompositeAdapter:

Collaboration diagram for prom::CompositeAdapter:

Public Member Functions
	CompositeAdapter (std::vector< AdapterPtr > adapters)
	Construct from an explicit list of adapters. Null entries are ignored.
	CompositeAdapter (const std::initializer_list< AdapterPtr > adapters)
	Convenience constructor: CompositeAdapter{a, b, c}.
std::span< const AdapterPtr >	adapters () const noexcept
	The wrapped adapters, in dispatch order (nulls already removed).
std::string_view	backend_name () const noexcept override
	Stable identifier of the backend (e.g. "null", "prometheus-cpp").
MetricHandle	register_metric (const MetricMeta &meta) noexcept override
	Register a metric family.
MetricHandle	resolve (const MetricHandle &family, const Labels &dynamic) noexcept override
	Resolve the labeled child of family for the given dynamic labels, creating it on first request.
void	inc (const MetricHandle &handle, const double amount) noexcept override
	Increase the series behind handle by amount (counter/gauge).
void	dec (const MetricHandle &handle, const double amount) noexcept override
	Decrease the series behind handle by amount (gauge).
void	set (const MetricHandle &handle, const double value) noexcept override
	Set the series behind handle to value (gauge/untyped).
void	observe (const MetricHandle &handle, const double value) noexcept override
	Record an observation against handle (histogram/summary).
void	set_info (const MetricHandle &handle, const std::span< const Label > labels) noexcept override
	Replace the label set carried by an info metric.
void	set_state (const MetricHandle &handle, const std::string_view state, const bool active) noexcept override
	Set the boolean value of one member of a state set.
void	set_unit (const MetricHandle &handle, const Unit &unit) noexcept override
	Late unit inference hook.
Public Member Functions inherited from prom::Adapter
	Adapter ()=default
	Adapter (const Adapter &)=delete
Adapter &	operator= (const Adapter &)=delete
	Adapter (Adapter &&)=delete
Adapter &	operator= (Adapter &&)=delete
virtual	~Adapter ()=default

Detailed Description

A backend that forwards every call to a fixed set of child adapters.

The adapter list is captured at construction and never mutated afterwards, so — given that each child honours the Adapter threading contract — the composite itself needs no locking and is safe to call from any thread. Null entries in the supplied list are dropped so child indices stay dense.

Constructor & Destructor Documentation

CompositeAdapter() [1/2]

prom::CompositeAdapter::CompositeAdapter ( std::vector< AdapterPtr >  adapters )

inlineexplicit

Construct from an explicit list of adapters. Null entries are ignored.

CompositeAdapter() [2/2]

prom::CompositeAdapter::CompositeAdapter ( const std::initializer_list< AdapterPtr >  adapters )

inline

Convenience constructor: CompositeAdapter{a, b, c}.

Member Function Documentation

adapters()

std::span< const AdapterPtr > prom::CompositeAdapter::adapters ( ) const

inlinenoexcept

The wrapped adapters, in dispatch order (nulls already removed).

backend_name()

std::string_view prom::CompositeAdapter::backend_name ( ) const

inlineoverridevirtualnoexcept

Stable identifier of the backend (e.g. "null", "prometheus-cpp").

Implements prom::Adapter.

dec()

void prom::CompositeAdapter::dec ( const MetricHandle &  handle, const double  amount  )

inlineoverridevirtualnoexcept

Decrease the series behind handle by amount (gauge).

Implements prom::Adapter.

inc()

void prom::CompositeAdapter::inc ( const MetricHandle &  handle, const double  amount  )

inlineoverridevirtualnoexcept

Increase the series behind handle by amount (counter/gauge).

Implements prom::Adapter.

observe()

void prom::CompositeAdapter::observe ( const MetricHandle &  handle, const double  value  )

inlineoverridevirtualnoexcept

Record an observation against handle (histogram/summary).

Implements prom::Adapter.

register_metric()

MetricHandle prom::CompositeAdapter::register_metric ( const MetricMeta &  meta )

inlineoverridevirtualnoexcept

Register a metric family.

Must return a non-null handle even on failure (fall back to an inert handle) so callers never have to null-check.

Implements prom::Adapter.

resolve()

MetricHandle prom::CompositeAdapter::resolve ( const MetricHandle &  family, const Labels &  dynamic  )

inlineoverridevirtualnoexcept

Resolve the labeled child of family for the given dynamic labels, creating it on first request.

The backend owns the child cache. Must return a non-null handle.

Implements prom::Adapter.

set()

void prom::CompositeAdapter::set ( const MetricHandle &  handle, const double  value  )

inlineoverridevirtualnoexcept

Set the series behind handle to value (gauge/untyped).

Implements prom::Adapter.

set_info()

void prom::CompositeAdapter::set_info ( const MetricHandle &  handle, const std::span< const Label >  labels  )

inlineoverridevirtualnoexcept

Replace the label set carried by an info metric.

Implements prom::Adapter.

set_state()

void prom::CompositeAdapter::set_state ( const MetricHandle &  handle, const std::string_view  state, const bool  active  )

inlineoverridevirtualnoexcept

Set the boolean value of one member of a state set.

Implements prom::Adapter.

set_unit()

void prom::CompositeAdapter::set_unit ( const MetricHandle &  , const Unit &    )

inlineoverridevirtualnoexcept

Late unit inference hook.

Called when a metric that declared no unit latches the unit of its first dimensional observation. Optional — backends that cannot rename a registered series may ignore it.

Reimplemented from prom::Adapter.

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

• include/prom/composite_adapter.hpp