DP_S/include/spdlog/sinks/kafka_sink.h

// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

//
// Custom sink for kafka
// Building and using requires librdkafka library.
// For building librdkafka library check the url below
// https://github.com/confluentinc/librdkafka
//

#include "spdlog/async.h"
#include "spdlog/details/log_msg.h"
#include "spdlog/details/null_mutex.h"
#include "spdlog/details/synchronous_factory.h"
#include "spdlog/sinks/base_sink.h"
#include <mutex>
#include <spdlog/common.h>

// kafka header
#include <librdkafka/rdkafkacpp.h>

namespace spdlog {
namespace sinks {

struct kafka_sink_config {
    std::string server_addr;
    std::string produce_topic;
    int32_t flush_timeout_ms = 1000;

    kafka_sink_config(std::string addr, std::string topic, int flush_timeout_ms = 1000)
        : server_addr{std::move(addr)},
          produce_topic{std::move(topic)},
          flush_timeout_ms(flush_timeout_ms) {}
};

template <typename Mutex>
class kafka_sink : public base_sink<Mutex> {
public:
    kafka_sink(kafka_sink_config config)
        : config_{std::move(config)} {
        try {
            std::string errstr;
            conf_.reset(RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL));
            RdKafka::Conf::ConfResult confRes =
                conf_->set("bootstrap.servers", config_.server_addr, errstr);
            if (confRes != RdKafka::Conf::CONF_OK) {
                throw_spdlog_ex(
                    fmt_lib::format("conf set bootstrap.servers failed err:{}", errstr));
            }

            tconf_.reset(RdKafka::Conf::create(RdKafka::Conf::CONF_TOPIC));
            if (tconf_ == nullptr) {
                throw_spdlog_ex(fmt_lib::format("create topic config failed"));
            }

            producer_.reset(RdKafka::Producer::create(conf_.get(), errstr));
            if (producer_ == nullptr) {
                throw_spdlog_ex(fmt_lib::format("create producer failed err:{}", errstr));
            }
            topic_.reset(RdKafka::Topic::create(producer_.get(), config_.produce_topic,
                                                tconf_.get(), errstr));
            if (topic_ == nullptr) {
                throw_spdlog_ex(fmt_lib::format("create topic failed err:{}", errstr));
            }
        } catch (const std::exception &e) {
            throw_spdlog_ex(fmt_lib::format("error create kafka instance: {}", e.what()));
        }
    }

    ~kafka_sink() { producer_->flush(config_.flush_timeout_ms); }

protected:
    void sink_it_(const details::log_msg &msg) override {
        producer_->produce(topic_.get(), 0, RdKafka::Producer::RK_MSG_COPY,
                           (void *)msg.payload.data(), msg.payload.size(), NULL, NULL);
    }

    void flush_() override { producer_->flush(config_.flush_timeout_ms); }

private:
    kafka_sink_config config_;
    std::unique_ptr<RdKafka::Producer> producer_ = nullptr;
    std::unique_ptr<RdKafka::Conf> conf_ = nullptr;
    std::unique_ptr<RdKafka::Conf> tconf_ = nullptr;
    std::unique_ptr<RdKafka::Topic> topic_ = nullptr;
};

using kafka_sink_mt = kafka_sink<std::mutex>;
using kafka_sink_st = kafka_sink<spdlog::details::null_mutex>;

}  // namespace sinks

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> kafka_logger_mt(const std::string &logger_name,
                                               spdlog::sinks::kafka_sink_config config) {
    return Factory::template create<sinks::kafka_sink_mt>(logger_name, config);
}

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> kafka_logger_st(const std::string &logger_name,
                                               spdlog::sinks::kafka_sink_config config) {
    return Factory::template create<sinks::kafka_sink_st>(logger_name, config);
}

template <typename Factory = spdlog::async_factory>
inline std::shared_ptr<spdlog::logger> kafka_logger_async_mt(
    std::string logger_name, spdlog::sinks::kafka_sink_config config) {
    return Factory::template create<sinks::kafka_sink_mt>(logger_name, config);
}

template <typename Factory = spdlog::async_factory>
inline std::shared_ptr<spdlog::logger> kafka_logger_async_st(
    std::string logger_name, spdlog::sinks::kafka_sink_config config) {
    return Factory::template create<sinks::kafka_sink_st>(logger_name, config);
}

}  // namespace spdlog