Collects system metrics and exports them to the text-based Prometheus format. More...

#include <prometheus.hpp>

Public Types
using	char_buffer = std::vector<char>
	A buffer for storing UTF-8 characters.

Public Member Functions
timespan	min_scrape_interval () const noexcept
	Returns the minimum scrape interval, i.e., the minimum time that needs to pass before `collect_from` iterates the registry to re-fill the buffer.

void	min_scrape_interval (timespan value) noexcept
	Sets the minimum scrape interval to `value`.

timestamp	last_scrape () const noexcept
	Returns the time point of the last scrape.

std::string_view	str () const noexcept
	Returns a string view into the internal buffer.

void	reset ()
	Reverts the collector back to its initial state, clearing all buffers.

bool	begin_scrape (timestamp now=make_timestamp())
	Begins a new scrape if `last_scape() + min_scrape_interval() <= now`.

void	end_scrape ()
	Cleans up any temporary state before accessing `str()` for obtaining the scrape result.

template<class T >
void	append_counter (const metric_family family, const metric instance, T value)

template<class T >
void	append_gauge (const metric_family family, const metric instance, T value)

void	append_histogram (const metric_family family, const metric instance, span< const int_histogram::bucket_type > buckets, int64_t sum)

void	append_histogram (const metric_family family, const metric instance, span< const dbl_histogram::bucket_type > buckets, double sum)

std::string_view	collect_from (const metric_registry &registry, timestamp now=make_timestamp())
	Applies this collector to the registry, filling the character buffer while collecting metrics.

void	operator() (const metric_family family, const metric instance, const dbl_counter *counter)

void	operator() (const metric_family family, const metric instance, const int_counter *counter)

void	operator() (const metric_family family, const metric instance, const dbl_gauge *gauge)

void	operator() (const metric_family family, const metric instance, const int_gauge *gauge)

void	operator() (const metric_family family, const metric instance, const dbl_histogram *val)

void	operator() (const metric_family family, const metric instance, const int_histogram *val)

Detailed Description

Collects system metrics and exports them to the text-based Prometheus format.

For a documentation of the format, see: https://git.io/fjgDD.

Member Typedef Documentation

◆ char_buffer

using caf::telemetry::collector::prometheus::char_buffer = std::vector<char>

A buffer for storing UTF-8 characters.

Using a vector instead of a std::string has slight performance benefits, since the vector does not have to maintain a null-terminator.

Member Function Documentation

◆ begin_scrape()

bool caf::telemetry::collector::prometheus::begin_scrape ( timestamp now = make_timestamp() )

nodiscard

Begins a new scrape if last_scape() + min_scrape_interval() <= now.

Returns: true if the collector started a new scrape or false to signal that the caller shall use the last result via str() since it has not expired yet.

◆ collect_from()

std::string_view caf::telemetry::collector::prometheus::collect_from	(	const metric_registry &	registry,
		timestamp	now = make_timestamp() )

Applies this collector to the registry, filling the character buffer while collecting metrics.

Automatically calls begin_scrape and end_scrape as needed.

Parameters

registry	Source for the metrics.
now	Current system time.

Returns: a view into the filled buffer.

◆ str()

std::string_view caf::telemetry::collector::prometheus::str ( ) const

nodiscardnoexcept

Returns a string view into the internal buffer.

Warning: This view may become invalid when calling any non-const member function on the collector object.

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

libcaf_core/caf/telemetry/collector/prometheus.hpp
libcaf_core/caf/telemetry/collector/prometheus.cpp

Public Types