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| -rw-r--r-- | wsrep-lib/include/wsrep/server_service.hpp | 264 |
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diff --git a/wsrep-lib/include/wsrep/server_service.hpp b/wsrep-lib/include/wsrep/server_service.hpp new file mode 100644 index 00000000..7701bc63 --- /dev/null +++ b/wsrep-lib/include/wsrep/server_service.hpp @@ -0,0 +1,264 @@ +/* + * Copyright (C) 2018 Codership Oy <info@codership.com> + * + * This file is part of wsrep-lib. + * + * Wsrep-lib is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * Wsrep-lib is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with wsrep-lib. If not, see <https://www.gnu.org/licenses/>. + */ + + +/** @file server_service.hpp + * + * An abstract interface for a DBMS server services. + * The interface will define methods which will be called from + * the wsrep-lib. + */ + +#ifndef WSREP_SERVER_SERVICE_HPP +#define WSREP_SERVER_SERVICE_HPP + +#include "logger.hpp" +#include "server_state.hpp" + +#include <string> + +namespace wsrep +{ + class client_service; + class storage_service; + class high_priority_service; + class ws_meta; + class gtid; + class view; + class server_service + { + public: + + virtual ~server_service() { } + virtual wsrep::storage_service* storage_service( + wsrep::client_service&) = 0; + virtual wsrep::storage_service* storage_service( + wsrep::high_priority_service&) = 0; + virtual void release_storage_service(wsrep::storage_service*) = 0; + + /** + * Create an applier state for streaming transaction applying. + * + * @param orig_cs Reference to client service which is + * requesting a new streaming applier service + * instance. + * + * @return Pointer to streaming applier client state. + */ + virtual wsrep::high_priority_service* + streaming_applier_service(wsrep::client_service& orig_cs) = 0; + + /** + * Create an applier state for streaming transaction applying. + * + * @param orig_hps Reference to high priority service which is + * requesting a new streaming applier service + * instance. + * + * @return Pointer to streaming applier client state. + */ + virtual wsrep::high_priority_service* + streaming_applier_service(wsrep::high_priority_service& orig_hps) = 0; + + /** + * Release a client state allocated by either local_client_state() + * or streaming_applier_client_state(). + */ + virtual void release_high_priority_service( + wsrep::high_priority_service*) = 0; + + /** + * Perform a background rollback for a transaction. + * + * @param lock Lock protecting client state. + * @param client_state Client session to do background rollback + * for. + */ + virtual void background_rollback(wsrep::unique_lock<wsrep::mutex>& lock, + wsrep::client_state& client_state) + = 0; + + /** + * Bootstrap a DBMS state for a new cluster. + * + * This method is called by the wsrep lib after the + * new cluster is bootstrapped and the server has reached + * initialized state. From this call the DBMS should initialize + * environment for the new cluster. + */ + virtual void bootstrap() = 0; + + /** + * Log message + * + * @param level Requested logging level + * @param message Message + */ + virtual void log_message(enum wsrep::log::level level, + const char* message) = 0; + /** + * Log a dummy write set. A dummy write set is usually either + * a remotely generated write set which failed certification in + * provider and had a GTID assigned or a streaming replication + * rollback write set. If the DBMS implements logging for + * applied transactions, logging dummy write sets which do not + * commit any transaction is neeeded to keep the GTID sequence + * continuous in the server. + */ + virtual void log_dummy_write_set(wsrep::client_state& client_state, + const wsrep::ws_meta& ws_meta) = 0; + + /** + * Log a cluster view change event. The method takes + * as an argument a pointer to high priority service associated + * to an applier thread if one is available. + * + * @param high_priority_service Pointer to high priority service + * @param view Reference to view object + */ + virtual void log_view( + wsrep::high_priority_service* high_priority_service, + const wsrep::view& view) = 0; + + /** + * Recover streaming appliers from the streaming log. + * The implementation must scan through log of stored streaming + * fragments and reconstruct the streaming applier service + * objects. + * + * This is overload for calls which are done from client context, + * e.g. after SST has been received. + * + * @param client_service Reference to client service object + */ + virtual void recover_streaming_appliers( + wsrep::client_service& client_service) = 0; + + /** + * Recover streaming appliers from the streaming log. + * The implementation must scan through log of stored streaming + * fragments and reconstruct the streaming applier service + * objects. + * + * This is overload for calls which are done from high priority + * context, e.g. when handling cluster view change events. + * + * @param high_priority_service Reference to high priority service + * object. + */ + virtual void recover_streaming_appliers( + wsrep::high_priority_service& high_priority_service) = 0; + + /** + * Recover a cluster view change event. + * The method takes own node ID. + * + * @param client_service Reference to client_service + * @param own_id this node ID obtained on connection to cluster + */ + virtual wsrep::view get_view( + wsrep::client_service& client_service, + const wsrep::id& own_id) = 0; + + /** + * Get the current replication position from the server + * storage. + * + * @param client_service Reference to client_service + * + * @return Current position GTID. + */ + virtual wsrep::gtid get_position( + wsrep::client_service& client_service) = 0; + + /** + * Set the current replication position of the server + * storage. + * + * @param client_service Reference to client_service + * @param gtid Reference to position to be set + */ + virtual void set_position( + wsrep::client_service& client_service, + const wsrep::gtid& gtid) = 0; + + /** + * Log a state change event. + * + * Note that this method may be called with server_state + * mutex locked, so calling server_state public methods + * should be avoided from within this call. + * + * @param prev_state Previous state server was in + * @param current_state Current state + */ + virtual void log_state_change( + enum wsrep::server_state::state prev_state, + enum wsrep::server_state::state current_state) = 0; + + /** + * Determine if the configured SST method requires SST to be + * performed before DBMS storage engine initialization. + * + * @return True if the SST must happen before storage engine init, + * otherwise false. + */ + virtual bool sst_before_init() const = 0; + + /** + * Return SST request which provides the donor server enough + * information how to donate the snapshot. + * + * @return A string containing a SST request. + */ + virtual std::string sst_request() = 0; + + /** + * Start a SST process. + * + * @param sst_request A string containing the SST request from + * the joiner + * @param gtid A GTID denoting the current replication position + * @param bypass Boolean bypass flag. + * + * @return Zero if the SST transfer was successfully started, + * non-zero otherwise. + */ + virtual int start_sst(const std::string& sst_request, + const wsrep::gtid& gtid, + bool bypass) = 0; + + + /** + * Wait until committing transactions have completed. + * Prior calling this method the server should have been + * desynced from the group to disallow further transactions + * to start committing. + */ + virtual int wait_committing_transactions(int timeout) = 0; + + /** + * Provide a server level debug sync point for a caller. + */ + virtual void debug_sync(const char* sync_point) = 0; + + }; +} + +#endif // WSREP_SERVER_SERVICE_HPP |