Add support for pyserial exclusive access mode.

Handy for preventing two applications from trying to access
the same port simultaneously.

Author: jameshilliard

examples/client_async.py

@@ -84,6 +84,7 @@ def setup_async_client(description=None, cmdline=None):
             #    bytesize=8,
             #    parity="N",
             #    stopbits=1,
+            #    exclusive=None,
             #    handle_local_echo=False,
         )
     elif args.comm == "tls":

examples/client_sync.py

@@ -93,6 +93,7 @@ def setup_sync_client(description=None, cmdline=None):
             #    bytesize=8,
             #    parity="N",
             #    stopbits=1,
+            #    exclusive=None,
             #    handle_local_echo=False,
         )
     elif args.comm == "tls":

examples/server_async.py

@@ -190,6 +190,7 @@ async def run_async_server(args):
             # bytesize=8,  # The bytesize of the serial messages
             # parity="N",  # Which kind of parity to use
             baudrate=args.baudrate,  # The baud rate to use for the serial device
+            # exclusive=None,  # The exclusive access mode (POSIX only)
             # handle_local_echo=False,  # Handle local echo of the USB-to-RS485 adaptor
             # ignore_missing_slaves=True,  # ignore request to a missing slave
             # broadcast_enable=False,  # treat slave_id 0 as broadcast address,

examples/server_sync.py

@@ -100,6 +100,7 @@ def run_sync_server(args):
             # bytesize=7,  # The bytesize of the serial messages
             # parity="E",  # Which kind of parity to use
             baudrate=args.baudrate,  # The baud rate to use for the serial device
+            # exclusive=None,  # The exclusive access mode (POSIX only)
             # handle_local_echo=False,  # Handle local echo of the USB-to-RS485 adaptor
             # ignore_missing_slaves=True,  # ignore request to a missing slave
             # broadcast_enable=False,  # treat slave_id 0 as broadcast address,

examples/simple_sync_client.py

@@ -65,6 +65,7 @@ def run_sync_simple_client(comm, host, port, framer=Framer.SOCKET):
             bytesize=8,
             parity="N",
             stopbits=1,
+            # exclusive=None,
             # handle_local_echo=False,
         )
     elif comm == "tls":

pymodbus/client/base.py

@@ -77,6 +77,7 @@ def __init__(
                 bytesize=kwargs.get("bytesize", None),
                 parity=kwargs.get("parity", None),
                 stopbits=kwargs.get("stopbits", None),
+                exclusive=kwargs.get("exclusive", None),
                 handle_local_echo=kwargs.get("handle_local_echo", False),
             ),
             False,
@@ -345,6 +346,7 @@ def __init__(  # pylint: disable=too-many-arguments
                 bytesize=kwargs.get("bytesize", None),
                 parity=kwargs.get("parity", None),
                 stopbits=kwargs.get("stopbits", None),
+                exclusive=kwargs.get("exclusive", None),
                 handle_local_echo=kwargs.get("handle_local_echo", False),
                 on_reconnect_callback = on_reconnect_callback,
             ),

pymodbus/client/serial.py

@@ -35,6 +35,7 @@ class AsyncModbusSerialClient(ModbusBaseClient, asyncio.Protocol):
     :param bytesize: Number of bits per byte 7-8.
     :param parity: 'E'ven, 'O'dd or 'N'one
     :param stopbits: Number of stop bits 1, 1.5, 2.
+    :param exclusive: Set exclusive access mode (POSIX only).
     :param handle_local_echo: Discard local echo from dongle.
 
     Common optional parameters:
@@ -72,6 +73,7 @@ def __init__(
         bytesize: int = 8,
         parity: str = "N",
         stopbits: int = 1,
+        exclusive: bool | None = None,
         **kwargs: Any,
     ) -> None:
         """Initialize Asyncio Modbus Serial Client."""
@@ -90,6 +92,7 @@ def __init__(
             bytesize=bytesize,
             parity=parity,
             stopbits=stopbits,
+            exclusive=exclusive,
             **kwargs,
         )
 
@@ -117,6 +120,7 @@ class ModbusSerialClient(ModbusBaseSyncClient):
     :param bytesize: Number of bits per byte 7-8.
     :param parity: 'E'ven, 'O'dd or 'N'one
     :param stopbits: Number of stop bits 0-2.
+    :param exclusive: Set exclusive access mode (POSIX only).
     :param handle_local_echo: Discard local echo from dongle.
 
     Common optional parameters:
@@ -162,6 +166,7 @@ def __init__(
         bytesize: int = 8,
         parity: str = "N",
         stopbits: int = 1,
+        exclusive: bool | None = None,
         **kwargs: Any,
     ) -> None:
         """Initialize Modbus Serial Client."""
@@ -173,6 +178,7 @@ def __init__(
             bytesize=bytesize,
             parity=parity,
             stopbits=stopbits,
+            exclusive=exclusive,
             **kwargs,
         )
         self.socket = None
@@ -210,6 +216,7 @@ def connect(self):
                 stopbits=self.comm_params.stopbits,
                 baudrate=self.comm_params.baudrate,
                 parity=self.comm_params.parity,
+                exclusive=self.comm_params.exclusive,
             )
             if self.params.strict:
                 self.socket.interCharTimeout = self.inter_char_timeout

pymodbus/repl/client/helper.py

@@ -59,6 +59,8 @@
     "set_baudrate",
     "get_timeout",
     "set_timeout",
+    "get_exclusive",
+    "set_exclusive",
     "get_serial_settings",
 ]
 CLIENT_ATTRIBUTES: list[str] = []

pymodbus/repl/client/main.py

@@ -388,6 +388,12 @@ def tcp(ctx, host, port, framer):
     default=2,
     type=float,
 )
+@click.option(
+    "--exclusive",
+    help="Set exclusive access mode (POSIX only).",
+    default=None,
+    type=bool,
+)
 def serial(  # pylint: disable=too-many-arguments
     ctx,
     method,
@@ -401,6 +407,7 @@ def serial(  # pylint: disable=too-many-arguments
     dsrdtr,
     timeout,
     write_timeout,
+    exclusive,
 ):
     """Define serial communication."""
     method = method.lower()
@@ -426,6 +433,7 @@ def serial(  # pylint: disable=too-many-arguments
         dsrdtr=dsrdtr,
         timeout=timeout,
         write_timeout=write_timeout,
+        exclusive=exclusive,
         **ctx.obj,
     )
     cli = CLI(client)

pymodbus/repl/client/mclient.py

@@ -658,6 +658,22 @@ def set_timeout(self, value):
         if self.is_socket_open():
             self.close()
 
+    def get_exclusive(self):
+        """Get exclusive access mode (POSIX only).
+
+        :return: Current exclusive access mode
+        """
+        return self.params.exclusive
+
+    def set_exclusive(self, value):
+        """Set exclusive access mode (POSIX only).
+
+        :param value: Possible values (True, False)
+        """
+        self.params.exclusive = bool(value)
+        if self.is_socket_open():
+            self.close()
+
     def get_serial_settings(self):
         """Get Current Serial port settings.
 
@@ -672,6 +688,7 @@ def get_serial_settings(self):
             "read timeout": self.comm_params.timeout_connect,
             "t1.5": self.inter_char_timeout,
             "t3.5": self.silent_interval,
+            "exclusive": self.comm_params.exclusive,
         }