Developed UserVarEvent and Added Statement-Based Logging Test (julien-duponchelle#466)

mjs1995 · heehehe · sean-k1 · web-flow · commit 73e2eeb7ac2a · 2023-09-01T18:27:20.000+02:00
Co-authored-by: heehehe &lt;heeseon0315@gmail.com&gt;
Co-authored-by: sean-k1 &lt;sean.k1@kakaoent.com&gt;
Co-authored-by: starcat37 &lt;starcat37@korea.ac.kr&gt;
Co-authored-by: minakiz &lt;k515jina@gmail.com&gt;
diff --git a/pymysqlreplication/binlogstream.py b/pymysqlreplication/binlogstream.py
@@ -14,7 +14,7 @@
     BeginLoadQueryEvent, ExecuteLoadQueryEvent,
     HeartbeatLogEvent, NotImplementedEvent, MariadbGtidEvent,
     MariadbAnnotateRowsEvent, RandEvent, MariadbStartEncryptionEvent, RowsQueryLogEvent,
-    MariadbGtidListEvent, MariadbBinLogCheckPointEvent)
+    MariadbGtidListEvent, MariadbBinLogCheckPointEvent, UserVarEvent)
 from .exceptions import BinLogNotEnabled
 from .gtid import GtidSet
 from .packet import BinLogPacketWrapper
@@ -626,7 +626,8 @@ def _allowed_event_list(self, only_events, ignored_events,
                 RandEvent,
                 MariadbStartEncryptionEvent,
                 MariadbGtidListEvent,
-                MariadbBinLogCheckPointEvent
+                MariadbBinLogCheckPointEvent,
+                UserVarEvent
             ))
         if ignored_events is not None:
             for e in ignored_events:
diff --git a/pymysqlreplication/event.py b/pymysqlreplication/event.py
@@ -3,8 +3,10 @@
 import binascii
 import struct
 import datetime
+import decimal
 from pymysqlreplication.constants.STATUS_VAR_KEY import *
 from pymysqlreplication.exceptions import StatusVariableMismatch
+from typing import Union, Optional
 
 
 class BinLogEvent(object):
@@ -51,7 +53,6 @@ def _dump(self):
         """Core data dumped for the event"""
         pass
 
-
 class GtidEvent(BinLogEvent):
     """GTID change in binlog event
     """
@@ -519,7 +520,6 @@ class RandEvent(BinLogEvent):
     :ivar seed1: int - value for the first seed
     :ivar seed2: int - value for the second seed
     """
-    
     def __init__(self, from_packet, event_size, table_map, ctl_connection, **kwargs):
         super().__init__(from_packet, event_size, table_map,
                                         ctl_connection, **kwargs)
@@ -542,6 +542,149 @@ def _dump(self):
         print("seed1: %d" % (self.seed1))
         print("seed2: %d" % (self.seed2))
 
+class UserVarEvent(BinLogEvent):
+    """
+    UserVarEvent is generated every time a statement uses a user variable.
+    Indicates the value to use for the user variable in the next statement.
+
+    :ivar name_len: int - Length of user variable
+    :ivar name: str - User variable name
+    :ivar value: str - Value of the user variable
+    :ivar type: int - Type of the user variable
+    :ivar charset: int - The number of the character set for the user variable
+    :ivar is_null: int - Non-zero if the variable value is the SQL NULL value, 0 otherwise
+    :ivar flags: int - Extra flags associated with the user variable
+    """
+
+    def __init__(self, from_packet, event_size, table_map, ctl_connection, **kwargs):
+        super(UserVarEvent, self).__init__(from_packet, event_size, table_map, ctl_connection, **kwargs)
+
+        # Payload
+        self.name_len: int = self.packet.read_uint32()
+        self.name: str = self.packet.read(self.name_len).decode()
+        self.is_null: int = self.packet.read_uint8()
+        self.type_to_codes_and_method: dict = {
+            0x00: ['STRING_RESULT', self._read_string],
+            0x01: ['REAL_RESULT', self._read_real],
+            0x02: ['INT_RESULT', self._read_int],
+            0x03: ['ROW_RESULT', self._read_default],
+            0x04: ['DECIMAL_RESULT', self._read_decimal]
+        }
+
+        self.value: Optional[Union[str, float, int, decimal.Decimal]] = None
+        self.flags: Optional[int] = None
+        self.temp_value_buffer: Union[bytes, memoryview] = b''
+
+        if not self.is_null:
+            self.type: int = self.packet.read_uint8()
+            self.charset: int = self.packet.read_uint32()
+            self.value_len: int = self.packet.read_uint32()
+            self.temp_value_buffer: Union[bytes, memoryview] = self.packet.read(self.value_len)
+            self.flags: int = self.packet.read_uint8()
+            self._set_value_from_temp_buffer()
+        else:
+            self.type, self.charset, self.value_len, self.value, self.flags = None, None, None, None, None
+
+    def _set_value_from_temp_buffer(self):
+        """
+        Set the value from the temporary buffer based on the type code.
+        """
+        if self.temp_value_buffer:
+            type_code, read_method = self.type_to_codes_and_method.get(self.type, ["UNKNOWN_RESULT", self._read_default])
+            if type_code == 'INT_RESULT':
+                self.value = read_method(self.temp_value_buffer, self.flags)
+            else:
+                self.value = read_method(self.temp_value_buffer)
+
+    def _read_string(self, buffer: bytes) -> str:
+        """
+        Read string data.
+        """
+        return buffer.decode()
+
+    def _read_real(self, buffer: bytes) -> float:
+        """
+        Read real data.
+        """
+        return struct.unpack('<d', buffer)[0]
+
+    def _read_int(self, buffer: bytes, flags: int) -> int:
+        """
+        Read integer data.
+        """
+        fmt = '<Q' if flags == 1 else '<q'
+        return struct.unpack(fmt, buffer)[0]
+
+    def _read_decimal(self, buffer: bytes) -> decimal.Decimal:
+        """
+        Read decimal data.
+        """
+        self.precision = self.temp_value_buffer[0]
+        self.decimals = self.temp_value_buffer[1]
+        raw_decimal = self.temp_value_buffer[2:]
+        return self._parse_decimal_from_bytes(raw_decimal, self.precision, self.decimals)
+
+    def _read_default(self) -> bytes:
+        """
+        Read default data.
+        Used when the type is None.
+        """
+        return self.packet.read(self.value_len)
+
+    @staticmethod
+    def _parse_decimal_from_bytes(raw_decimal: bytes, precision: int, decimals: int) -> decimal.Decimal:
+        """
+        Parse decimal from bytes.
+        """
+        digits_per_integer = 9
+        compressed_bytes = [0, 1, 1, 2, 2, 3, 3, 4, 4, 4]
+        integral = precision - decimals
+
+        uncomp_integral, comp_integral = divmod(integral, digits_per_integer)
+        uncomp_fractional, comp_fractional = divmod(decimals, digits_per_integer)
+
+        res = "-" if not raw_decimal[0] & 0x80 else ""
+        mask = -1 if res == "-" else 0
+        raw_decimal = bytearray([raw_decimal[0] ^ 0x80]) + raw_decimal[1:]
+
+        def decode_decimal_decompress_value(comp_indx, data, mask):
+            size = compressed_bytes[comp_indx]
+            if size > 0:
+                databuff = bytearray(data[:size])
+                for i in range(size):
+                    databuff[i] = (databuff[i] ^ mask) & 0xFF
+                return size, int.from_bytes(databuff, byteorder='big')
+            return 0, 0
+
+        pointer, value = decode_decimal_decompress_value(comp_integral, raw_decimal, mask)
+        res += str(value)
+
+        for _ in range(uncomp_integral):
+            value = struct.unpack('>i', raw_decimal[pointer:pointer+4])[0] ^ mask
+            res += '%09d' % value
+            pointer += 4
+
+        res += "."
+
+        for _ in range(uncomp_fractional):
+            value = struct.unpack('>i', raw_decimal[pointer:pointer+4])[0] ^ mask
+            res += '%09d' % value
+            pointer += 4
+
+        size, value = decode_decimal_decompress_value(comp_fractional, raw_decimal[pointer:], mask)
+        if size > 0:
+            res += '%0*d' % (comp_fractional, value)
+        return decimal.Decimal(res)
+
+    def _dump(self) -> None:
+        super(UserVarEvent, self)._dump()
+        print("User variable name: %s" % self.name)
+        print("Is NULL: %s" % ("Yes" if self.is_null else "No"))
+        if not self.is_null:
+            print("Type: %s" % self.type_to_codes_and_method.get(self.type, ['UNKNOWN_TYPE'])[0])
+            print("Charset: %s" % self.charset)
+            print("Value: %s" % self.value)
+            print("Flags: %s" % self.flags)
 
 class MariadbStartEncryptionEvent(BinLogEvent):
     """
diff --git a/pymysqlreplication/packet.py b/pymysqlreplication/packet.py
@@ -72,6 +72,7 @@ class BinLogPacketWrapper(object):
         constants.XA_PREPARE_EVENT: event.XAPrepareEvent,
         constants.ROWS_QUERY_LOG_EVENT: event.RowsQueryLogEvent,
         constants.RAND_EVENT: event.RandEvent,
+        constants.USER_VAR_EVENT: event.UserVarEvent,
         # row_event
         constants.UPDATE_ROWS_EVENT_V1: row_event.UpdateRowsEvent,
         constants.WRITE_ROWS_EVENT_V1: row_event.WriteRowsEvent,
diff --git a/pymysqlreplication/tests/test_basic.py b/pymysqlreplication/tests/test_basic.py
