component.hpp

Go to the documentation of this file.

#pragma once
 
/// @file userver/storages/mysql/component.hpp
/// @brief @copybrief storages::mysql::Component
 
#include <memory>
 
#include <userver/components/component_base.hpp>
#include <userver/utils/statistics/entry.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace clients::dns {
class Component;
}
 
namespace storages::mysql {
class Cluster;
}
 
namespace storages::mysql {
 
// clang-format off
/// @ingroup userver_components
///
/// @brief MySQL/MariaDB client component
///
/// Provides access to a MySQL/MariaDB cluster.
///
/// ## Static configuration example:
///
/// @snippet samples/mysql_service/static_config.yaml  MySQL service sample - static config
///
/// The component will lookup connection data in secdist.json via its name.
///
/// ## Secdist format:
///
/// Connection settings are described as a JSON object `mysql_settings`,
/// containing descriptions of MySQL/MariaDB clusters.
///
/// @snippet samples/mysql_service/tests/conftest.py  Mysql service sample - secdist
///
/// **Important note**: the uMySQL driver does **NOT** perform an automatic
/// primary detection and always considers the first host in `hosts` list
/// an only primary node in the cluster.
///
/// ## Static options (more to come)
/// Name                     | Description                                 | Default value
/// -------------------------|---------------------------------------------|---------------
/// initial_pool_size        | initial connection pool size (per host)     | 5
/// max_pool_size            | maximum connection pool size (per host)     | 10
///
// clang-format on
class Component final : public components::ComponentBase {
public:
    /// Component constructor
    Component(const components::ComponentConfig& config, const components::ComponentContext& context);
 
    /// Component destructor
    ~Component() override;
 
    /// Cluster accessor
    std::shared_ptr<storages::mysql::Cluster> GetCluster() const;
 
    static yaml_config::Schema GetStaticConfigSchema();
 
private:
    clients::dns::Component& dns_;
 
    const std::shared_ptr<storages::mysql::Cluster> cluster_;
    utils::statistics::Entry statistics_holder_;
};
 
}  // namespace storages::mysql
 
USERVER_NAMESPACE_END