Prometheus.hpp

//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2023, the clio developers.
 
    Permission to use, copy, modify, and distribute this software for any
    purpose with or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#pragma once
 
#include "util/log/Logger.hpp"
#include "util/prometheus/Bool.hpp"
#include "util/prometheus/Counter.hpp"
#include "util/prometheus/Gauge.hpp"
#include "util/prometheus/Histogram.hpp"
#include "util/prometheus/Label.hpp"
#include "util/prometheus/MetricBase.hpp"
#include "util/prometheus/MetricsFamily.hpp"
 
#include <concepts>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <unordered_map>
#include <vector>
 
namespace util::prometheus {

class PrometheusInterface {
public:
    PrometheusInterface(bool isEnabled, bool compressReply)
        : isEnabled_(isEnabled), compressReplyEnabled_(compressReply)
    {
    }
 
    virtual ~PrometheusInterface() = default;

    virtual Bool
    boolMetric(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual CounterInt&
    counterInt(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual CounterDouble&
    counterDouble(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual GaugeInt&
    gaugeInt(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual GaugeDouble&
    gaugeDouble(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual HistogramInt&
    histogramInt(
        std::string name,
        Labels labels,
        std::vector<std::int64_t> const& buckets,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual HistogramDouble&
    histogramDouble(
        std::string name,
        Labels labels,
        std::vector<double> const& buckets,
        std::optional<std::string> description = std::nullopt
    ) = 0;

    virtual std::string
    collectMetrics() = 0;

    bool
    isEnabled() const
    {
        return isEnabled_;
    }

    bool
    compressReplyEnabled() const
    {
        return compressReplyEnabled_;
    }
 
private:
    bool isEnabled_;
    bool compressReplyEnabled_;
};

class PrometheusImpl : public PrometheusInterface {
public:
    using PrometheusInterface::PrometheusInterface;
 
    Bool
    boolMetric(
        std::string name,
        Labels labels,
        std::optional<std::string> description = std::nullopt
    ) override;
 
    CounterInt&
    counterInt(std::string name, Labels labels, std::optional<std::string> description) override;
 
    CounterDouble&
    counterDouble(std::string name, Labels labels, std::optional<std::string> description) override;
 
    GaugeInt&
    gaugeInt(std::string name, Labels labels, std::optional<std::string> description) override;
 
    GaugeDouble&
    gaugeDouble(std::string name, Labels labels, std::optional<std::string> description) override;
 
    HistogramInt&
    histogramInt(
        std::string name,
        Labels labels,
        std::vector<std::int64_t> const& buckets,
        std::optional<std::string> description = std::nullopt
    ) override;
 
    HistogramDouble&
    histogramDouble(
        std::string name,
        Labels labels,
        std::vector<double> const& buckets,
        std::optional<std::string> description = std::nullopt
    ) override;
 
    std::string
    collectMetrics() override;
 
private:
    MetricsFamily&
    getMetricsFamily(std::string name, std::optional<std::string> description, MetricType type);
 
    MetricBase&
    getMetric(
        std::string name,
        Labels labels,
        std::optional<std::string> description,
        MetricType type
    );
 
    template <typename ValueType>
        requires std::same_as<ValueType, std::int64_t> || std::same_as<ValueType, double>
    MetricBase&
    getMetric(
        std::string name,
        Labels labels,
        std::optional<std::string> description,
        MetricType type,
        std::vector<ValueType> const& buckets
    );
 
    std::unordered_map<std::string, MetricsFamily> metrics_;
};
 
}  // namespace util::prometheus

class PrometheusService {
public:
    static void
    init(util::config::ClioConfigDefinition const& config);

    static bool
    isInitialised();

    static util::prometheus::Bool
    boolMetric(
        std::string name,
        util::prometheus::Labels labels,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::CounterInt&
    counterInt(
        std::string name,
        util::prometheus::Labels labels,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::CounterDouble&
    counterDouble(
        std::string name,
        util::prometheus::Labels labels,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::GaugeInt&
    gaugeInt(
        std::string name,
        util::prometheus::Labels labels,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::GaugeDouble&
    gaugeDouble(
        std::string name,
        util::prometheus::Labels labels,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::HistogramInt&
    histogramInt(
        std::string name,
        util::prometheus::Labels labels,
        std::vector<std::int64_t> const& buckets,
        std::optional<std::string> description = std::nullopt
    );

    static util::prometheus::HistogramDouble&
    histogramDouble(
        std::string name,
        util::prometheus::Labels labels,
        std::vector<double> const& buckets,
        std::optional<std::string> description = std::nullopt
    );

    static std::string
    collectMetrics();

    static bool
    isEnabled();

    static bool
    compressReplyEnabled();

    static void
    replaceInstance(std::unique_ptr<util::prometheus::PrometheusInterface> inst);

    static util::prometheus::PrometheusInterface&
    instance();
 
private:
    static std::unique_ptr<util::prometheus::PrometheusInterface> impl;
};