Limit use of Singleton.

Author: janiversen

pymodbus/client/mixin.py

@@ -9,6 +9,7 @@
 import pymodbus.other_message as pdu_other_msg
 import pymodbus.register_read_message as pdu_reg_read
 import pymodbus.register_write_message as pdu_req_write
+from pymodbus.constants import INTERNAL_ERROR
 from pymodbus.exceptions import ModbusException
 from pymodbus.pdu import ModbusRequest, ModbusResponse
 
@@ -53,7 +54,7 @@ def execute(self, request: ModbusRequest) -> ModbusResponse:
         .. tip::
             Response is not interpreted.
         """
-        raise ModbusException("Pymodbus internal ERROR")
+        raise ModbusException(INTERNAL_ERROR)
 
     def read_coils(
         self, address: int, count: int = 1, slave: int = 0, **kwargs: Any

pymodbus/constants.py

@@ -4,11 +4,10 @@
 values for the servers and clients.
 """
 
+INTERNAL_ERROR = "Pymodbus internal error"
 
-from pymodbus.interfaces import Singleton
 
-
-class Defaults(Singleton):  # pylint: disable=too-few-public-methods
+class Defaults:  # pylint: disable=too-few-public-methods
     """A collection of modbus default values.
 
      .. attribute:: Port
@@ -155,8 +154,12 @@ class Defaults(Singleton):  # pylint: disable=too-few-public-methods
     ReconnectDelayMax = 1000 * 60 * 5
     Count = 1
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
+
 
-class ModbusStatus(Singleton):  # pylint: disable=too-few-public-methods
+class ModbusStatus:  # pylint: disable=too-few-public-methods
     """These represent various status codes in the modbus protocol.
 
     .. attribute:: Waiting
@@ -193,8 +196,12 @@ class ModbusStatus(Singleton):  # pylint: disable=too-few-public-methods
     SlaveOn = 0xFF
     SlaveOff = 0x00
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
 
-class Endian(Singleton):  # pylint: disable=too-few-public-methods
+
+class Endian:  # pylint: disable=too-few-public-methods
     """An enumeration representing the various byte endianness.
 
     .. attribute:: Auto
@@ -218,8 +225,12 @@ class Endian(Singleton):  # pylint: disable=too-few-public-methods
     Big = ">"
     Little = "<"
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
+
 
-class ModbusPlusOperation(Singleton):  # pylint: disable=too-few-public-methods
+class ModbusPlusOperation:  # pylint: disable=too-few-public-methods
     """Represents the type of modbus plus request.
 
     .. attribute:: GetStatistics
@@ -236,8 +247,12 @@ class ModbusPlusOperation(Singleton):  # pylint: disable=too-few-public-methods
     GetStatistics = 0x0003
     ClearStatistics = 0x0004
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
 
-class DeviceInformation(Singleton):  # pylint: disable=too-few-public-methods
+
+class DeviceInformation:  # pylint: disable=too-few-public-methods
     """Represents what type of device information to read.
 
     .. attribute:: Basic
@@ -269,8 +284,12 @@ class DeviceInformation(Singleton):  # pylint: disable=too-few-public-methods
     Extended = 0x03
     Specific = 0x04
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
+
 
-class MoreData(Singleton):  # pylint: disable=too-few-public-methods
+class MoreData:  # pylint: disable=too-few-public-methods
     """Represents the more follows condition.
 
     .. attribute:: Nothing
@@ -285,6 +304,10 @@ class MoreData(Singleton):  # pylint: disable=too-few-public-methods
     Nothing = 0x00
     KeepReading = 0xFF
 
+    def __init__(self):
+        """Prohibit objects."""
+        raise RuntimeError(INTERNAL_ERROR)
+
 
 # ---------------------------------------------------------------------------#
 #  Exported Identifiers

pymodbus/pdu.py

@@ -4,7 +4,6 @@
 
 from pymodbus.constants import Defaults
 from pymodbus.exceptions import NotImplementedException
-from pymodbus.interfaces import Singleton
 from pymodbus.logging import Log
 from pymodbus.utilities import rtuFrameSize
 
@@ -145,7 +144,7 @@ def isError(self):
 # --------------------------------------------------------------------------- #
 # Exception PDUs
 # --------------------------------------------------------------------------- #
-class ModbusExceptions(Singleton):  # pylint: disable=too-few-public-methods
+class ModbusExceptions:  # pylint: disable=too-few-public-methods
     """An enumeration of the valid modbus exceptions."""
 
     IllegalFunction = 0x01