skip the first 2 events after reconnected

* sleep 5s after disconnected accidently and skip the first 2
  events after reconnected
* some cleanup and compacting works

Author: woods-chen

pymysqlreplication/binlogstream.py

@@ -2,6 +2,7 @@
 
 import pymysql
 import struct
+import time
 from distutils.version import LooseVersion
 
 from pymysql.constants.COMMAND import COM_BINLOG_DUMP, COM_REGISTER_SLAVE
@@ -30,6 +31,7 @@
 # 2006 MySQL server has gone away
 MYSQL_EXPECTED_ERROR_CODES = [2013, 2006]
 
+__PYMYSQL_VERSION_LT_06 = pymysql.__version__ < LooseVersion("0.6")
 
 class ReportSlave(object):
 
@@ -208,11 +210,6 @@ def __init__(self, connection_settings, server_id,
             each time the client is disconnected and then auto-reconnected
             to the mysql server (OperationalError 2006/2013) if resume_stream
             is False. so it's suggested to set resume_stream to True.
-
-            an additional RotateEvent and FormatDescriptionEvent will be
-            fetched each time the client is disconnected and then auto-
-            reconnected to the server. (no matter resume_stream is True
-            or False)
         """
 
         self.__connection_settings = connection_settings
@@ -263,7 +260,7 @@ def __init__(self, connection_settings, server_id,
             self.pymysql_wrapper = pymysql.connect
 
     def close(self):
-        if getattr(self, '_stream_connection', None) and self._stream_connection.open:
+        if self.__connected_stream:
             self._stream_connection.close()
         if getattr(self, '_ctl_connection', None):
             # break reference cycle between stream reader and underlying
@@ -304,7 +301,7 @@ def _register_slave(self):
 
         packet = self.report_slave.encoded(self.__server_id)
 
-        if pymysql.__version__ < LooseVersion("0.6"):
+        if __PYMYSQL_VERSION_LT_06:
             self._stream_connection.wfile.write(packet)
             self._stream_connection.wfile.flush()
             self._stream_connection.read_packet()
@@ -334,7 +331,7 @@ def __connect_to_stream(self, force_reconnect=False):
         # server_id (4) -- server id of this slave
         # log_file (string.EOF) -- filename of the binlog on the master
         self._stream_connection = self.pymysql_wrapper(**self.__connection_settings)
-        if pymysql.__version__ < LooseVersion("0.6"):
+        if __PYMYSQL_VERSION_LT_06:
             self._stream_connection._read_packet = self._stream_connection.read_packet
 
         self.__use_checksum = self.__checksum_enabled()
@@ -467,7 +464,7 @@ def __connect_to_stream(self, force_reconnect=False):
             # encoded_data
             prelude += gtid_set.encoded()
 
-        if pymysql.__version__ < LooseVersion("0.6"):
+        if __PYMYSQL_VERSION_LT_06:
             self._stream_connection.wfile.write(prelude)
             self._stream_connection.wfile.flush()
         else:
@@ -493,7 +490,10 @@ def __fetchone(self):
             except pymysql.OperationalError as error:
                 code, message = error.args
                 if code in MYSQL_EXPECTED_ERROR_CODES:
+                    time.sleep(5)
                     self.__connect_to_stream(force_reconnect=True)
+                    # skip the first 2 events (RotateEvent and FormatDescriptionEvent)
+                    _ = self.__fetchone(), self.__fetchone()
                     continue
                 raise