add API to set max until disconnect. (#2521)

Author: janiversen

pymodbus/client/base.py

@@ -83,6 +83,20 @@ def execute(self, no_response_expected: bool, request: ModbusPDU):
             raise ConnectionException(f"Not connected[{self!s}]")
         return self.ctx.execute(no_response_expected, request)
 
+    def set_max_no_responses(self, max_count: int) -> None:
+        """Override default max no request responses.
+
+        :param max_count: Max aborted requests before disconnecting.
+
+        The parameter retries defines how many times a request is retried
+        before being aborted. Once aborted a counter is incremented, and when
+        this counter is greater than max_count the connection is terminated.
+
+        .. tip::
+            When a request is successful the count is reset.
+        """
+        self.ctx.max_until_disconnect = max_count
+
     async def __aenter__(self):
         """Implement the client with enter block.
 
@@ -185,6 +199,20 @@ def execute(self, no_response_expected: bool, request: ModbusPDU) -> ModbusPDU:
             raise ConnectionException(f"Failed to connect[{self!s}]")
         return self.transaction.sync_execute(no_response_expected, request)
 
+    def set_max_no_responses(self, max_count: int) -> None:
+        """Override default max no request responses.
+
+        :param max_count: Max aborted requests before disconnecting.
+
+        The parameter retries defines how many times a request is retried
+        before being aborted. Once aborted a counter is incremented, and when
+        this counter is greater than max_count the connection is terminated.
+
+        .. tip::
+            When a request is successful the count is reset.
+        """
+        self.transaction.max_until_disconnect = max_count
+
     # ----------------------------------------------------------------------- #
     # Internal methods
     # ----------------------------------------------------------------------- #

pymodbus/transaction/transaction.py

@@ -53,8 +53,7 @@ def __init__(
         self.trace_packet = trace_packet or self.dummy_trace_packet
         self.trace_pdu = trace_pdu or self.dummy_trace_pdu
         self.trace_connect = trace_connect or self.dummy_trace_connect
-        self.accept_no_response_limit = retries + 3
-        self.count_no_responses = 0
+        self.max_until_disconnect = self.count_until_disconnect = retries + 3
         if sync_client:
             self.sync_client = sync_client
             self._sync_lock = RLock()
@@ -109,12 +108,12 @@ def sync_execute(self, no_response_expected: bool, request: ModbusPDU) -> Modbus
                     return self.sync_get_response()
                 except asyncio.exceptions.TimeoutError:
                     count_retries += 1
-            if self.count_no_responses >= self.accept_no_response_limit:
+            if self.count_until_disconnect < 0:
                 self.connection_lost(asyncio.TimeoutError("Server not responding"))
                 raise ModbusIOException(
-                    f"ERROR: No response received of the last {self.accept_no_response_limit} request, CLOSING CONNECTION."
+                    "ERROR: No response received of the last requests (default: retries+3), CLOSING CONNECTION."
                 )
-            self.count_no_responses += 1
+            self.count_until_disconnect -= 1
             txt = f"No response received after {self.retries} retries, continue with next request"
             Log.error(txt)
             raise ModbusIOException(txt)
@@ -141,16 +140,16 @@ async def execute(self, no_response_expected: bool, request: ModbusPDU) -> Modbu
                     response = await asyncio.wait_for(
                         self.response_future, timeout=self.comm_params.timeout_connect
                     )
-                    self.count_no_responses = 0
+                    self.count_until_disconnect= self.max_until_disconnect
                     return response
                 except asyncio.exceptions.TimeoutError:
                     count_retries += 1
-            if self.count_no_responses >= self.accept_no_response_limit:
+            if self.count_until_disconnect < 0:
                 self.connection_lost(asyncio.TimeoutError("Server not responding"))
                 raise ModbusIOException(
-                    f"ERROR: No response received of the last {self.accept_no_response_limit} request, CLOSING CONNECTION."
+                    "ERROR: No response received of the last requests (default: retries+3), CLOSING CONNECTION."
                 )
-            self.count_no_responses += 1
+            self.count_until_disconnect -= 1
             txt = f"No response received after {self.retries} retries, continue with next request"
             Log.error(txt)
             raise ModbusIOException(txt)
@@ -175,7 +174,7 @@ def callback_new_connection(self):
 
     def callback_connected(self) -> None:
         """Call when connection is succcesfull."""
-        self.count_no_responses = 0
+        self.count_until_disconnect = self.max_until_disconnect
         self.next_tid = 0
         self.trace_connect(True)
 

test/client/test_client.py

@@ -368,6 +368,7 @@ async def test_client_modbusbaseclient(self):
         )
         client.register(pdu_bit.ReadCoilsResponse)
         assert str(client)
+        client.set_max_no_responses(110)
         client.close()
 
     async def test_client_connection_made(self):

test/client/test_client_sync.py

@@ -188,7 +188,7 @@ def test_tcp_client_repr(self):
             f"ipaddr={client.comm_params.host}, port={client.comm_params.port}, timeout={client.comm_params.timeout_connect}>"
         )
         assert repr(client) == rep
-
+        client.set_max_no_responses(110)
 
 class TestSyncClientTls:
     """Unittest for the pymodbus.client module."""