cluster_types.hpp

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#pragma once
 
/// @file userver/storages/postgres/cluster_types.hpp
/// @brief Cluster properties
 
#include <string>
 
#include <userver/utils/flags.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace logging {
class LogHelper;
}  // namespace logging
 
namespace storages::postgres {
 
enum class ClusterHostType {
    /// @name Cluster roles
    /// @{
    /// No host role detected yet.
    kNone = 0x00,
    /// Connect to cluster's master. Only this connection may be
    /// used for read-write transactions.
    kMaster = 0x01,
    /// Connect to cluster's sync slave. May fallback to master. Can be used only
    /// for read only transactions.
    /// @warning Not available for clusters with quorum commit,
    /// prefer kSlave or kMaster.
    kSyncSlave = 0x02,
    /// Connect to one of cluster's slaves. May fallback to master. Can be used
    /// only for read only transactions.
    kSlave = 0x04,
    /// Connect to either a master or to a slave, whatever the host selection
    /// strategy chooses. Can be used only for read only transactions.
    kSlaveOrMaster = kMaster | kSlave,
    /// @}
 
    /// @name Host selection strategies
    /// @{
 
    /// Chooses a host using the round-robin algorithm
    kRoundRobin = 0x08,
 
    /// Chooses a host with the lowest RTT
    kNearest = 0x10,
    /// @}
};
 
using ClusterHostTypeFlags = USERVER_NAMESPACE::utils::Flags<ClusterHostType>;
 
constexpr ClusterHostTypeFlags
    kClusterHostRolesMask{ClusterHostType::kMaster, ClusterHostType::kSyncSlave, ClusterHostType::kSlave};
 
constexpr ClusterHostTypeFlags kClusterHostStrategyMask{ClusterHostType::kRoundRobin, ClusterHostType::kNearest};
 
std::string ToString(ClusterHostType);
std::string ToString(ClusterHostTypeFlags);
logging::LogHelper& operator<<(logging::LogHelper&, ClusterHostType);
logging::LogHelper& operator<<(logging::LogHelper&, ClusterHostTypeFlags);
 
struct ClusterHostTypeHash {
    size_t operator()(ClusterHostType ht) const noexcept { return static_cast<size_t>(ht); }
};
 
}  // namespace storages::postgres
 
USERVER_NAMESPACE_END