component.hpp

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#pragma once
 
/// @file userver/ydb/component.hpp
/// @brief @copybrief ydb::YdbComponent
 
#include <memory>
#include <string>
#include <unordered_map>
 
#include <userver/components/component_base.hpp>
#include <userver/dynamic_config/source.hpp>
#include <userver/formats/json.hpp>
#include <userver/utils/statistics/fwd.hpp>
#include <userver/utils/statistics/storage.hpp>
 
#include <userver/ydb/fwd.hpp>
 
#include <ydb-cpp-sdk/client/driver/fwd.h>
 
USERVER_NAMESPACE_BEGIN
 
namespace ydb {
 
namespace impl {
class Driver;
}  // namespace impl
 
// clang-format off
 
/// @ingroup userver_components
///
/// @brief YDB client component
///
/// Provides access to ydb::TableClient, ydb::TopicClient, ydb::CoordinationClient.
///
/// ## Static options:
/// Name | Description | Default value
/// ---- | ----------- | -------------
/// `credentials-provider` | name of credentials provider component | -
/// `operation-settings.retries` | default retries count for an operation | 3
/// `operation-settings.operation-timeout` | default operation timeout in utils::StringToDuration() format | 1s
/// `operation-settings.cancel-after` | cancel operation after specified string in utils::StringToDuration() format | 1s
/// `operation-settings.client-timeout` | default client timeout in utils::StringToDuration() format | 1s
/// `operation-settings.get-session-timeout` | default session timeout in milliseconds | 5s
/// `databases.<dbname>.endpoint` | gRPC endpoint URL, e.g. grpc://localhost:1234 | -
/// `databases.<dbname>.database` | full database path, e.g. /ru/service/production/database | -
/// `databases.<dbname>.credentials` | credentials config passed to credentials provider component | -
/// `databases.<dbname>.min_pool_size` | minimum pool size for database with name `<dbname>` | 10
/// `databases.<dbname>.max_pool_size` | maximum pool size for database with name `<dbname>` | 50
/// `databases.<dbname>.get_session_retry_limit` | retries count to get session, every attempt with a get-session-timeout | 5
/// `databases.<dbname>.keep-in-query-cache` | whether to use query cache | true
/// `databases.<dbname>.prefer_local_dc` | prefer making requests to local DataCenter | false
/// `databases.<dbname>.aliases` | list of alias names for this database | []
/// `databases.<dbname>.sync_start` | fail on boot time if YDB is not accessible | true
/// `databases.<dbname>.by-database-timings-buckets-ms` | histogram bounds for by-database timing metrics | 40 buckets with +20% increment per step
/// `databases.<dbname>.by-query-timings-buckets-ms` | histogram bounds for by-query timing metrics | 15 buckets with +100% increment per step
 
// clang-format on
 
class YdbComponent final : public components::ComponentBase {
public:
    /// @ingroup userver_component_names
    /// @brief The default name of ydb::YdbComponent component
    static constexpr std::string_view kName = "ydb";
 
    YdbComponent(const components::ComponentConfig&, const components::ComponentContext&);
 
    ~YdbComponent();
 
    /// Get table client
    /// @param dbname database name from static config key
    std::shared_ptr<TableClient> GetTableClient(const std::string& dbname) const;
 
    /// Get topic client
    /// @param dbname database name from static config key
    std::shared_ptr<TopicClient> GetTopicClient(const std::string& dbname) const;
 
    /// Get coordination client
    /// @param dbname database name from static config key
    std::shared_ptr<CoordinationClient> GetCoordinationClient(const std::string& dbname) const;
 
    /// Get native driver
    /// @param dbname database name from static config key
    /// @warning Use with care! Facilities from
    /// `<core/include/userver/drivers/subscribable_futures.hpp>` can help with
    /// non-blocking wait operations.
    const NYdb::TDriver& GetNativeDriver(const std::string& dbname) const;
 
    /// Get database path
    /// @param dbname database name from static config key
    const std::string& GetDatabasePath(const std::string& dbname) const;
 
    static yaml_config::Schema GetStaticConfigSchema();
 
private:
    struct DatabaseUtils;
 
    struct Database {
        std::shared_ptr<impl::Driver> driver;
        std::shared_ptr<TableClient> table_client;
        std::shared_ptr<TopicClient> topic_client;
        std::shared_ptr<CoordinationClient> coordination_client;
    };
 
    void OnConfigUpdate(const dynamic_config::Snapshot& cfg);
    void WriteStatistics(utils::statistics::Writer& writer) const;
    const Database& FindDatabase(const std::string& dbname) const;
 
    std::unordered_map<std::string, Database> databases_;
 
    dynamic_config::Source config_;
 
    // These fields must be the last ones
    concurrent::AsyncEventSubscriberScope config_subscription_;
    utils::statistics::Entry statistic_holder_;
};
 
}  // namespace ydb
 
template <>
inline constexpr bool components::kHasValidate<ydb::YdbComponent> = true;
 
USERVER_NAMESPACE_END