mirror of
https://github.com/OpenNebula/one.git
synced 2024-12-22 13:33:52 +03:00
398 lines
11 KiB
C++
398 lines
11 KiB
C++
/* -------------------------------------------------------------------------- */
|
|
/* Copyright 2002-2018, OpenNebula Project, OpenNebula Systems */
|
|
/* */
|
|
/* Licensed under the Apache License, Version 2.0 (the "License"); you may */
|
|
/* not use this file except in compliance with the License. You may obtain */
|
|
/* a copy of the License at */
|
|
/* */
|
|
/* http://www.apache.org/licenses/LICENSE-2.0 */
|
|
/* */
|
|
/* Unless required by applicable law or agreed to in writing, software */
|
|
/* distributed under the License is distributed on an "AS IS" BASIS, */
|
|
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
|
|
/* See the License for the specific language governing permissions and */
|
|
/* limitations under the License. */
|
|
/* -------------------------------------------------------------------------- */
|
|
|
|
#ifndef LOG_DB_H_
|
|
#define LOG_DB_H_
|
|
|
|
#include <string>
|
|
#include <sstream>
|
|
#include <set>
|
|
|
|
#include "SqlDB.h"
|
|
|
|
/**
|
|
* This class represents a log record
|
|
*/
|
|
class LogDBRecord : public Callbackable
|
|
{
|
|
public:
|
|
/**
|
|
* Index for this log entry (and previous)
|
|
*/
|
|
unsigned int index;
|
|
|
|
unsigned int prev_index;
|
|
|
|
/**
|
|
* Term where this log (and previous) entry was generated
|
|
*/
|
|
unsigned int term;
|
|
|
|
unsigned int prev_term;
|
|
|
|
/**
|
|
* SQL command to exec in the DB to update (INSERT, REPLACE, DROP)
|
|
*/
|
|
std::string sql;
|
|
|
|
/**
|
|
* Time when the record has been applied to DB. 0 if not applied
|
|
*/
|
|
time_t timestamp;
|
|
|
|
/**
|
|
* The index in the federation, -1 if the log entry is not federated.
|
|
* At master fed_index is equal to index.
|
|
*/
|
|
int fed_index;
|
|
|
|
/**
|
|
* Sets callback to load register from DB
|
|
*/
|
|
void set_callback()
|
|
{
|
|
Callbackable::set_callback(
|
|
static_cast<Callbackable::Callback>(&LogDBRecord::select_cb));
|
|
}
|
|
|
|
private:
|
|
/**
|
|
* SQL callback to load logDBRecord from DB (SELECT commands)
|
|
*/
|
|
int select_cb(void *nil, int num, char **values, char **names);
|
|
};
|
|
|
|
/**
|
|
* This class implements a generic DB interface with replication. The associated
|
|
* DB stores a log to replicate on followers.
|
|
*/
|
|
class LogDB : public SqlDB, Callbackable
|
|
{
|
|
public:
|
|
LogDB(SqlDB * _db, bool solo, unsigned int log_retention);
|
|
|
|
virtual ~LogDB();
|
|
|
|
// -------------------------------------------------------------------------
|
|
// Interface to access Log records
|
|
// -------------------------------------------------------------------------
|
|
/**
|
|
* Loads a log record from the database. Memory is allocated by this class
|
|
* and needs to be freed.
|
|
* @param index of the associated logDB entry
|
|
* @param lr logDBrecored to load from the DB
|
|
* @return 0 on success -1 otherwise
|
|
*/
|
|
int get_log_record(unsigned int index, LogDBRecord& lr);
|
|
|
|
/**
|
|
* Applies the SQL command of the given record to the database. The
|
|
* timestamp of the record is updated.
|
|
* @param index of the log record
|
|
*/
|
|
int apply_log_records(unsigned int commit_index);
|
|
|
|
/**
|
|
* Deletes the record in start_index and all that follow it
|
|
* @param start_index first log record to delete
|
|
*/
|
|
int delete_log_records(unsigned int start_index);
|
|
|
|
/**
|
|
* Inserts a new log record in the database. This method should be used
|
|
* in FOLLOWER mode to replicate leader log.
|
|
* @param index for the record
|
|
* @param term for the record
|
|
* @param sql command of the record
|
|
* @param timestamp associated to this record
|
|
* @param fed_index index in the federation -1 if not federated
|
|
*
|
|
* @return -1 on failure, index of the inserted record on success
|
|
*/
|
|
int insert_log_record(unsigned int index, unsigned int term,
|
|
std::ostringstream& sql, time_t timestamp, int fed_index);
|
|
|
|
//--------------------------------------------------------------------------
|
|
// Functions to manage the Raft state. Log record 0, term -1
|
|
// -------------------------------------------------------------------------
|
|
/**
|
|
* Stores the raft state in the log
|
|
* @param raft attributes in XML format
|
|
* @return 0 on success
|
|
*/
|
|
int update_raft_state(std::string& raft_xml);
|
|
|
|
/**
|
|
* Returns the raft state attributes as stored in the log
|
|
* @param raft_xml attributes in xml
|
|
* @return 0 on success
|
|
*/
|
|
int get_raft_state(std::string &raft_xml);
|
|
|
|
/**
|
|
* Purge log records. Delete old records applied to database upto the
|
|
* LOG_RETENTION configuration variable.
|
|
* @return 0 on success
|
|
*/
|
|
int purge_log();
|
|
|
|
// -------------------------------------------------------------------------
|
|
// SQL interface
|
|
// -------------------------------------------------------------------------
|
|
/**
|
|
* This function replicates the DB changes on followers before updating
|
|
* the DB state
|
|
*/
|
|
int exec_wr(ostringstream& cmd)
|
|
{
|
|
return _exec_wr(cmd, -1);
|
|
}
|
|
|
|
int exec_federated_wr(ostringstream& cmd)
|
|
{
|
|
return _exec_wr(cmd, 0);
|
|
}
|
|
|
|
int exec_federated_wr(ostringstream& cmd, int index)
|
|
{
|
|
return _exec_wr(cmd, index);
|
|
}
|
|
|
|
int exec_local_wr(ostringstream& cmd)
|
|
{
|
|
return db->exec_local_wr(cmd);
|
|
}
|
|
|
|
int exec_rd(ostringstream& cmd, Callbackable* obj)
|
|
{
|
|
return db->exec_rd(cmd, obj);
|
|
}
|
|
|
|
char * escape_str(const string& str)
|
|
{
|
|
return db->escape_str(str);
|
|
}
|
|
|
|
void free_str(char * str)
|
|
{
|
|
db->free_str(str);
|
|
}
|
|
|
|
bool multiple_values_support()
|
|
{
|
|
return db->multiple_values_support();
|
|
}
|
|
|
|
// -------------------------------------------------------------------------
|
|
// Database methods
|
|
// -------------------------------------------------------------------------
|
|
static int bootstrap(SqlDB *_db);
|
|
|
|
/**
|
|
* This function gets and initialize log related index
|
|
* @param last_applied, highest index applied to the DB
|
|
* @param last_index
|
|
*
|
|
* @return 0 on success
|
|
*/
|
|
int setup_index(int& last_applied, int& last_index);
|
|
|
|
/**
|
|
* Gets the index & term of the last record in the log
|
|
* @param _i the index
|
|
* @param _t the term
|
|
*/
|
|
void get_last_record_index(unsigned int& _i, unsigned int& _t);
|
|
|
|
// -------------------------------------------------------------------------
|
|
// Federate log methods
|
|
// -------------------------------------------------------------------------
|
|
/**
|
|
* Get last federated index, and previous
|
|
*/
|
|
int last_federated();
|
|
|
|
int previous_federated(int index);
|
|
|
|
int next_federated(int index);
|
|
|
|
protected:
|
|
int exec(std::ostringstream& cmd, Callbackable* obj, bool quiet)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
private:
|
|
pthread_mutex_t mutex;
|
|
|
|
/**
|
|
* The Database was started in solo mode (no server_id defined)
|
|
*/
|
|
bool solo;
|
|
|
|
/**
|
|
* Pointer to the underlying DB store
|
|
*/
|
|
SqlDB * db;
|
|
|
|
/**
|
|
* Index to be used by the next logDB record
|
|
*/
|
|
unsigned int next_index;
|
|
|
|
/**
|
|
* Index of the last log entry applied to the DB state
|
|
*/
|
|
unsigned int last_applied;
|
|
|
|
/**
|
|
* Index of the last (highest) log entry
|
|
*/
|
|
unsigned int last_index;
|
|
|
|
/**
|
|
* term of the last (highest) log entry
|
|
*/
|
|
unsigned int last_term;
|
|
|
|
/**
|
|
* Max number of records to keep in the database
|
|
*/
|
|
unsigned int log_retention;
|
|
|
|
// -------------------------------------------------------------------------
|
|
// Federated Log
|
|
// -------------------------------------------------------------------------
|
|
/**
|
|
* The federated log stores a map with the federated log index and its
|
|
* corresponding local index. For the master both are the same
|
|
*/
|
|
std::set<int> fed_log;
|
|
|
|
/**
|
|
* Generates the federated index, it should be called whenever a server
|
|
* takes leadership.
|
|
*/
|
|
void build_federated_index();
|
|
|
|
// -------------------------------------------------------------------------
|
|
// DataBase implementation
|
|
// -------------------------------------------------------------------------
|
|
static const char * table;
|
|
|
|
static const char * db_names;
|
|
|
|
static const char * db_bootstrap;
|
|
|
|
/**
|
|
* Replicates writes in the followers and apply changes to DB state once
|
|
* it is safe to do so.
|
|
*
|
|
* @param federated -1 not federated (fed_index = -1), 0 generate fed index
|
|
* (fed_index = index), > 0 set (fed_index = federated)
|
|
*/
|
|
int _exec_wr(ostringstream& cmd, int federated);
|
|
|
|
/**
|
|
* Callback to store the IDs of federated records in the federated log.
|
|
*/
|
|
int index_cb(void *null, int num, char **values, char **names);
|
|
|
|
/**
|
|
* Applies the SQL command of the given record to the database. The
|
|
* timestamp of the record is updated.
|
|
* @param lr the log record
|
|
*/
|
|
int apply_log_record(LogDBRecord * lr);
|
|
|
|
/**
|
|
* Inserts or update a log record in the database
|
|
* @param index of the log entry
|
|
* @param term for the log entry
|
|
* @param sql command to modify DB state
|
|
* @param ts timestamp of record application to DB state
|
|
* @param fi the federated index -1 if none
|
|
*
|
|
* @return 0 on success
|
|
*/
|
|
int insert(int index, int term, const std::string& sql, time_t ts, int fi);
|
|
|
|
/**
|
|
* Inserts a new log record in the database. If the record is successfully
|
|
* inserted the index is incremented
|
|
* @param term for the record
|
|
* @param sql command of the record
|
|
* @param timestamp associated to this record
|
|
* @param federated, if true it will set fed_index == index, -1 otherwise
|
|
*
|
|
* @return -1 on failure, index of the inserted record on success
|
|
*/
|
|
int insert_log_record(unsigned int term, std::ostringstream& sql,
|
|
time_t timestamp, int federated);
|
|
};
|
|
|
|
// -----------------------------------------------------------------------------
|
|
// This is a LogDB decoration, it replicates the DB write commands on slaves
|
|
// It should be passed as DB for federated pools.
|
|
// -----------------------------------------------------------------------------
|
|
class FedLogDB: public SqlDB
|
|
{
|
|
public:
|
|
FedLogDB(LogDB *db):_logdb(db){};
|
|
|
|
virtual ~FedLogDB(){};
|
|
|
|
int exec_wr(ostringstream& cmd);
|
|
|
|
int exec_local_wr(ostringstream& cmd)
|
|
{
|
|
return _logdb->exec_local_wr(cmd);
|
|
}
|
|
|
|
int exec_rd(ostringstream& cmd, Callbackable* obj)
|
|
{
|
|
return _logdb->exec_rd(cmd, obj);
|
|
}
|
|
|
|
char * escape_str(const string& str)
|
|
{
|
|
return _logdb->escape_str(str);
|
|
}
|
|
|
|
void free_str(char * str)
|
|
{
|
|
_logdb->free_str(str);
|
|
}
|
|
|
|
bool multiple_values_support()
|
|
{
|
|
return _logdb->multiple_values_support();
|
|
}
|
|
|
|
protected:
|
|
int exec(std::ostringstream& cmd, Callbackable* obj, bool quiet)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
private:
|
|
|
|
LogDB * _logdb;
|
|
};
|
|
|
|
#endif /*LOG_DB_H_*/
|
|
|