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MXS-2785: Add rewrite_src and rewrite_dest parameters

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The parameters allow rudimentary database rewriting in the replication
stream. This is still very limited as the replacement must have the same
length as the original. In theory it could be shorter without causing
problems but making it longer is not easy.
This commit is contained in:
Markus Mäkelä 2019-12-03 13:58:04 +02:00
parent c480a44852
commit e829cae8b1
No known key found for this signature in database
GPG Key ID: 72D48FCE664F7B19
4 changed files with 55 additions and 12 deletions
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25
server/modules/filter/binlogfilter/binlogfilter.cc
View File

@ -34,8 +34,10 @@ extern "C" MXS_MODULE* MXS_CREATE_MODULE()
NULL,
NULL,
{
{"match", MXS_MODULE_PARAM_REGEX },
{"exclude", MXS_MODULE_PARAM_REGEX },
{"match", MXS_MODULE_PARAM_REGEX },
{"exclude", MXS_MODULE_PARAM_REGEX },
{REWRITE_SRC, MXS_MODULE_PARAM_STRING },
{REWRITE_DEST, MXS_MODULE_PARAM_STRING },
{MXS_END_MODULE_PARAMS}
}
};
@ -58,7 +60,24 @@ BinlogFilter::~BinlogFilter()
BinlogFilter* BinlogFilter::create(const char* zName,
MXS_CONFIG_PARAMETER* pParams)
{
return new BinlogFilter(pParams);
BinlogFilter* rval = nullptr;
auto src = pParams->get_string(REWRITE_SRC);
auto dest = pParams->get_string(REWRITE_DEST);
if (src.empty() != dest.empty())
{
MXS_ERROR("Both '%s' and '%s' must be defined", REWRITE_SRC, REWRITE_DEST);
}
else if (src.length() != dest.length())
{
MXS_ERROR("Both '%s' and '%s' must have the same length", REWRITE_SRC, REWRITE_DEST);
}
else
{
rval = new BinlogFilter(pParams);
}
return rval;
}
// BinlogFilterSession create routine

7
server/modules/filter/binlogfilter/binlogfilter.hh
View File

@ -18,6 +18,9 @@
#include <maxscale/pcre2.hh>
#include "binlogfiltersession.hh"
static constexpr const char REWRITE_SRC[] = "rewrite_src";
static constexpr const char REWRITE_DEST[] = "rewrite_dest";
// Binlog Filter configuration
struct BinlogConfig
{
@ -26,6 +29,8 @@ struct BinlogConfig
, md_match(match ? pcre2_match_data_create_from_pattern(match, nullptr) : nullptr)
, exclude(pParams->get_compiled_regex("exclude", 0, nullptr).release())
, md_exclude(exclude ? pcre2_match_data_create_from_pattern(exclude, nullptr) : nullptr)
, rewrite_src(pParams->get_string(REWRITE_SRC))
, rewrite_dest(pParams->get_string(REWRITE_DEST))
{
}
@ -33,6 +38,8 @@ struct BinlogConfig
pcre2_match_data* md_match;
pcre2_code* exclude;
pcre2_match_data* md_exclude;
std::string rewrite_src;
std::string rewrite_dest;
};
class BinlogFilter : public maxscale::Filter<BinlogFilter, BinlogFilterSession>

32
server/modules/filter/binlogfilter/binlogfiltersession.cc
View File

@ -305,11 +305,9 @@ bool BinlogFilterSession::checkEvent(GWBUF* buffer,
case QUERY_EVENT:
// Handle the SQL statement: DDL, DML, BEGIN, COMMIT
// If statement is COMMIT, then continue with next case.
if (checkStatement(body, body_size))
{
break;
}
checkStatement(body, body_size);
fixEvent(event + MYSQL_HEADER_LEN + 1, hdr.event_size, hdr);
break;
case XID_EVENT:
/** Note: This case is reached when event_type is
@ -792,7 +790,7 @@ void BinlogFilterSession::handleEventData(uint32_t len)
* @param event_size The binlog event size
* @return False for COMMIT, true otherwise
*/
bool BinlogFilterSession::checkStatement(const uint8_t* event, const uint32_t event_size)
bool BinlogFilterSession::checkStatement(uint8_t* event, const uint32_t event_size)
{
int db_name_len = event[4 + 4];
int var_block_len_offset = 4 + 4 + 1 + 2;
@ -803,9 +801,29 @@ bool BinlogFilterSession::checkStatement(const uint8_t* event, const uint32_t ev
std::string db((char*)event + static_size + var_block_len, db_name_len);
std::string sql((char*)event + static_size + var_block_len + db_name_len + 1, statement_len);
m_skip = should_skip_query(m_filter.getConfig(), sql, db);
const auto& config = m_filter.getConfig();
m_skip = should_skip_query(config, sql, db);
MXS_INFO("[%s] (%s) %s", m_skip ? "SKIP" : " ", db.c_str(), sql.c_str());
if (!m_skip && !config.rewrite_src.empty())
{
if (db == config.rewrite_src)
{
db = config.rewrite_dest;
}
while (char* p = strstr(&sql[0], config.rewrite_src.c_str()))
{
memcpy(p, config.rewrite_dest.c_str(), config.rewrite_dest.length());
}
mxb_assert(db.length() == (size_t)db_name_len);
mxb_assert(sql.length() == (size_t)statement_len);
memcpy(event + static_size + var_block_len, db.c_str(), db_name_len);
memcpy(event + static_size + var_block_len + db_name_len + 1, sql.c_str(), statement_len);
MXS_INFO("Rename: (%s) %s", db.c_str(), sql.c_str());
}
return true;
}

3
server/modules/filter/binlogfilter/binlogfiltersession.hh
View File

@ -100,8 +100,7 @@ private:
void handleEventData(uint32_t len);
// Check SQL statement in QUERY_EVENT
bool checkStatement(const uint8_t* event,
const uint32_t event_size);
bool checkStatement(uint8_t* event, const uint32_t event_size);
// Check DB.TABLE in ANNOTATE_ROWS event
void checkAnnotate(const uint8_t* event,