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/* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2009 Sun Microsystems, Inc.
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
*
* Defines the implementation of a simple replicator that can filter
* events based on a schema or table name.
*
* @details
*
* This is a very simple implementation. All we do is maintain two
* std::vectors:
*
* 1) contains all the schema names to filter
* 2) contains all the table names to filter
*
* If an event is on a schema or table in the vectors described above, then
* the event will not be passed along to the applier.
*/
#include <config.h>
#include <drizzled/gettext.h>
#include <drizzled/plugin/transaction_applier.h>
#include <drizzled/message/transaction.pb.h>
#include <drizzled/plugin.h>
#include <drizzled/item/string.h>
#include "filtered_replicator.h"
#include <boost/program_options.hpp>
#include <drizzled/module/option_map.h>
#include <vector>
#include <string>
namespace po= boost::program_options;
using namespace std;
using namespace drizzled;
namespace drizzle_plugin
{
static string sysvar_filtered_replicator_sch_filters;
static string sysvar_filtered_replicator_tab_filters;
FilteredReplicator::FilteredReplicator(string name_arg,
const std::string &sch_filter,
const std::string &tab_filter,
const std::string &sch_regex,
const std::string &tab_regex) :
plugin::TransactionReplicator(name_arg),
schemas_to_filter(),
tables_to_filter(),
_sch_filter(sch_filter),
_tab_filter(tab_filter),
_sch_regex(sch_regex),
_tab_regex(tab_regex),
sch_re(NULL),
tab_re(NULL)
{
/*
* Add each of the specified schemas to the vector of schemas
* to filter.
*/
if (not _sch_filter.empty())
{
populateFilter(_sch_filter, schemas_to_filter);
}
/*
* Add each of the specified tables to the vector of tables
* to filter.
*/
if (not _tab_filter.empty())
{
populateFilter(_tab_filter, tables_to_filter);
}
/*
* Compile the regular expression for schema's to filter
* if one is specified.
*/
if (not _sch_regex.empty())
{
const char *error= NULL;
int32_t error_offset= 0;
sch_re= pcre_compile(_sch_regex.c_str(),
0,
&error,
&error_offset,
NULL);
}
/*
* Compile the regular expression for table's to filter
* if one is specified.
*/
if (not _tab_regex.empty())
{
const char *error= NULL;
int32_t error_offset= 0;
tab_re= pcre_compile(_tab_regex.c_str(),
0,
&error,
&error_offset,
NULL);
}
pthread_mutex_init(&sch_vector_lock, NULL);
pthread_mutex_init(&tab_vector_lock, NULL);
pthread_mutex_init(&sysvar_sch_lock, NULL);
pthread_mutex_init(&sysvar_tab_lock, NULL);
}
FilteredReplicator::~FilteredReplicator()
{
if (sch_re)
{
pcre_free(sch_re);
}
if (tab_re)
{
pcre_free(tab_re);
}
pthread_mutex_destroy(&sch_vector_lock);
pthread_mutex_destroy(&tab_vector_lock);
pthread_mutex_destroy(&sysvar_sch_lock);
pthread_mutex_destroy(&sysvar_tab_lock);
}
void FilteredReplicator::parseStatementTableMetadata(const message::Statement &in_statement,
string &in_schema_name,
string &in_table_name) const
{
switch (in_statement.type())
{
case message::Statement::INSERT:
{
const message::TableMetadata &metadata= in_statement.insert_header().table_metadata();
in_schema_name= metadata.schema_name();
in_table_name= metadata.table_name();
break;
}
case message::Statement::UPDATE:
{
const message::TableMetadata &metadata= in_statement.update_header().table_metadata();
in_schema_name= metadata.schema_name();
in_table_name= metadata.table_name();
break;
}
case message::Statement::DELETE:
{
const message::TableMetadata &metadata= in_statement.delete_header().table_metadata();
in_schema_name= metadata.schema_name();
in_table_name= metadata.table_name();
break;
}
case message::Statement::CREATE_SCHEMA:
{
in_schema_name= in_statement.create_schema_statement().schema().name();
in_table_name.clear();
break;
}
case message::Statement::ALTER_SCHEMA:
{
in_schema_name= in_statement.alter_schema_statement().after().name();
in_table_name.clear();
break;
}
case message::Statement::DROP_SCHEMA:
{
in_schema_name= in_statement.drop_schema_statement().schema_name();
in_table_name.clear();
break;
}
case message::Statement::CREATE_TABLE:
{
in_schema_name= in_statement.create_table_statement().table().schema();
in_table_name= in_statement.create_table_statement().table().name();
break;
}
case message::Statement::ALTER_TABLE:
{
in_schema_name= in_statement.alter_table_statement().after().schema();
in_table_name= in_statement.alter_table_statement().after().name();
break;
}
case message::Statement::DROP_TABLE:
{
const message::TableMetadata &metadata= in_statement.drop_table_statement().table_metadata();
in_schema_name= metadata.schema_name();
in_table_name= metadata.table_name();
break;
}
default:
{
/* All other types have no schema and table information */
in_schema_name.clear();
in_table_name.clear();
break;
}
}
}
plugin::ReplicationReturnCode
FilteredReplicator::replicate(plugin::TransactionApplier *in_applier,
Session &in_session,
message::Transaction &to_replicate)
{
string schema_name;
string table_name;
size_t num_statements= to_replicate.statement_size();
/*
* We build a new transaction message containing only Statement
* messages that have not been filtered.
*
* @todo A more efficient method would be to rework the pointers
* that the to_replicate.statement() vector contains and remove
* the statement pointers that are filtered...
*/
message::Transaction filtered_transaction;
for (size_t x= 0; x < num_statements; ++x)
{
schema_name.clear();
table_name.clear();
const message::Statement &statement= to_replicate.statement(x);
/*
* First, we check to see if the command consists of raw SQL. If so,
* we need to parse this SQL and determine whether to filter the event
* based on the information we obtain from the parsed SQL.
* If not raw SQL, check if this event should be filtered or not
* based on the schema and table names in the command message.
*
* The schema and table names are stored in TableMetadata headers
* for most types of Statement messages.
*/
if (statement.type() == message::Statement::RAW_SQL)
{
parseQuery(statement.sql(), schema_name, table_name);
}
else
{
parseStatementTableMetadata(statement, schema_name, table_name);
}
/*
* Convert the schema name and table name strings to lowercase so that it
* does not matter what case the table or schema name was specified in. We
* also keep all entries in the vectors of schemas and tables to filter in
* lowercase.
*/
boost::to_lower(schema_name);
boost::to_lower(table_name);
if (! isSchemaFiltered(schema_name) && ! isTableFiltered(table_name))
{
message::Statement *s= filtered_transaction.add_statement();
*s= statement; /* copy contruct */
}
}
if (filtered_transaction.statement_size() > 0)
{
/*
* We can now simply call the applier's apply() method, passing
* along the supplied command.
*/
message::TransactionContext *tc= filtered_transaction.mutable_transaction_context();
*tc= to_replicate.transaction_context(); /* copy construct */
return in_applier->apply(in_session, filtered_transaction);
}
return plugin::SUCCESS;
}
void FilteredReplicator::populateFilter(std::string input,
std::vector<string> &filter)
{
/*
* Convert the input string to lowercase so that all entries in the vector
* will be in lowercase.
*/
boost::to_lower(input);
string::size_type last_pos= input.find_first_not_of(',', 0);
string::size_type pos= input.find_first_of(',', last_pos);
while (pos != string::npos || last_pos != string::npos)
{
filter.push_back(input.substr(last_pos, pos - last_pos));
last_pos= input.find_first_not_of(',', pos);
pos= input.find_first_of(',', last_pos);
}
}
bool FilteredReplicator::isSchemaFiltered(const string &schema_name)
{
pthread_mutex_lock(&sch_vector_lock);
std::vector<string>::iterator it= find(schemas_to_filter.begin(), schemas_to_filter.end(), schema_name);
if (it != schemas_to_filter.end())
{
pthread_mutex_unlock(&sch_vector_lock);
return true;
}
pthread_mutex_unlock(&sch_vector_lock);
/*
* If regular expression matching is enabled for schemas to filter, then
* we check to see if this schema name matches the regular expression that
* has been specified.
*/
if (not _sch_regex.empty())
{
int32_t result= pcre_exec(sch_re, NULL, schema_name.c_str(), schema_name.length(), 0, 0, NULL, 0);
if (result >= 0)
return true;
}
return false;
}
bool FilteredReplicator::isTableFiltered(const string &table_name)
{
pthread_mutex_lock(&tab_vector_lock);
std::vector<string>::iterator it= find(tables_to_filter.begin(), tables_to_filter.end(), table_name);
if (it != tables_to_filter.end())
{
pthread_mutex_unlock(&tab_vector_lock);
return true;
}
pthread_mutex_unlock(&tab_vector_lock);
/*
* If regular expression matching is enabled for tables to filter, then
* we check to see if this table name matches the regular expression that
* has been specified.
*/
if (not _tab_regex.empty())
{
int32_t result= pcre_exec(tab_re, NULL, table_name.c_str(), table_name.length(), 0, 0, NULL, 0);
if (result >= 0)
return true;
}
return false;
}
void FilteredReplicator::parseQuery(const string &sql,
string &schema_name,
string &table_name)
{
/*
* Determine what type of SQL we are dealing with e.g. create table,
* drop table, etc.
*/
string::size_type pos= sql.find_first_of(' ', 0);
string type= sql.substr(0, pos);
/*
* Convert the type string to uppercase here so that it doesn't
* matter what case the user entered the statement in.
*/
boost::to_upper(type);
if (type.compare("DROP") == 0)
{
/*
* The schema and table name can be either the third word
* or the fifth word in a DROP TABLE statement...so we extract
* the third word from the SQL and see whether it is and IF or
* not.
*/
pos= sql.find_first_of(' ', 11);
string cmp_str= sql.substr(11, pos - 11);
string target_name("");
if (cmp_str.compare("IF") == 0)
{
/* the name must be the fifth word */
pos= sql.find_first_of(' ', 21);
target_name= sql.substr(21, pos - 21);
}
else
{
target_name= cmp_str;
}
/*
* Determine whether the name is a concatenation of the schema
* name and table name i.e. schema.table or just the table name
* on its own.
*/
pos= target_name.find_first_of('.', 0);
if (pos != string::npos)
{
/*
* There is a schema name here...
*/
schema_name= target_name.substr(0, pos);
/*
* The rest of the name string is the table name.
*/
table_name= target_name.substr(pos + 1);
}
else
{
table_name= target_name;
}
}
else if (type.compare("CREATE") == 0)
{
/*
* The schema and table name are always the third word
* in a CREATE TABLE statement...always (unless there is
* some crazy syntax I am unaware of).
*/
pos= sql.find_first_of(' ', 13);
string target_name= sql.substr(13, pos - 13);
/*
* Determine whether the name is a concatenation of the schema
* name and table name i.e. schema.table or just the table name
* on its own.
*/
pos= target_name.find_first_of('.', 0);
if (pos != string::npos)
{
/*
* There is a schema name here...
*/
schema_name= target_name.substr(0, pos);
/*
* The rest of the name string is the table name.
*/
table_name= target_name.substr(pos + 1);
}
else
{
table_name= target_name;
}
}
else
{
/* we only deal with DROP and CREATE table for the moment */
return;
}
}
void FilteredReplicator::setSchemaFilter(const string &input)
{
pthread_mutex_lock(&sch_vector_lock);
pthread_mutex_lock(&sysvar_sch_lock);
_sch_filter= input;
schemas_to_filter.clear();
populateFilter(_sch_filter, schemas_to_filter);
pthread_mutex_unlock(&sysvar_sch_lock);
pthread_mutex_unlock(&sch_vector_lock);
}
void FilteredReplicator::setTableFilter(const string &input)
{
pthread_mutex_lock(&tab_vector_lock);
pthread_mutex_lock(&sysvar_tab_lock);
_tab_filter= input;
tables_to_filter.clear();
populateFilter(_tab_filter, tables_to_filter);
pthread_mutex_unlock(&sysvar_tab_lock);
pthread_mutex_unlock(&tab_vector_lock);
}
static FilteredReplicator *filtered_replicator= NULL; /* The singleton replicator */
static int filtered_schemas_validate(Session*, set_var *var)
{
const char *input= var->value->str_value.ptr();
if (input && filtered_replicator)
{
filtered_replicator->setSchemaFilter(input);
return 0;
}
return 1;
}
static int filtered_tables_validate(Session*, set_var *var)
{
const char *input= var->value->str_value.ptr();
if (input && filtered_replicator)
{
filtered_replicator->setTableFilter(input);
return 0;
}
return 1;
}
static int init(module::Context &context)
{
const module::option_map &vm= context.getOptions();
filtered_replicator= new FilteredReplicator("filtered_replicator",
vm["filteredschemas"].as<string>(),
vm["filteredtables"].as<string>(),
vm["schemaregex"].as<string>(),
vm["tableregex"].as<string>());
context.add(filtered_replicator);
context.registerVariable(new sys_var_std_string("filteredschemas",
sysvar_filtered_replicator_sch_filters,
filtered_schemas_validate));
context.registerVariable(new sys_var_std_string("filteredtables",
sysvar_filtered_replicator_tab_filters,
filtered_tables_validate));
context.registerVariable(new sys_var_const_string_val("schemaregex",
vm["schemaregex"].as<string>()));
context.registerVariable(new sys_var_const_string_val("tableregex",
vm["tableregex"].as<string>()));
return 0;
}
static void init_options(drizzled::module::option_context &context)
{
context("filteredschemas",
po::value<string>(&sysvar_filtered_replicator_sch_filters)->default_value(""),
N_("Comma-separated list of schemas to exclude"));
context("filteredtables",
po::value<string>(&sysvar_filtered_replicator_tab_filters)->default_value(""),
N_("Comma-separated list of tables to exclude"));
context("schemaregex",
po::value<string>()->default_value(""),
N_("Regular expression to apply to schemas to exclude"));
context("tableregex",
po::value<string>()->default_value(""),
N_("Regular expression to apply to tables to exclude"));
}
} /* namespace drizzle_plugin */
DRIZZLE_PLUGIN(drizzle_plugin::init, NULL, drizzle_plugin::init_options);
|