Adding an example and adding tcp timeout

doc/sphinx/examples/custom-datablock.rst

@@ -0,0 +1,6 @@
+==================================================
+Custom Datablock Example
+==================================================
+
+.. literalinclude:: ../../../examples/common/custom-datablock.py
+

examples/common/custom-datablock.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python
+'''
+Pymodbus Server With Custom Datablock Side Effect
+--------------------------------------------------------------------------
+
+This is an example of performing custom logic after a value has been
+written to the datastore.
+'''
+#---------------------------------------------------------------------------# 
+# import the modbus libraries we need
+#---------------------------------------------------------------------------# 
+from pymodbus.server.async import StartTcpServer
+from pymodbus.device import ModbusDeviceIdentification
+from pymodbus.datastore import ModbusSparseDataBlock
+from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext
+from pymodbus.transaction import ModbusRtuFramer, ModbusAsciiFramer
+
+#---------------------------------------------------------------------------# 
+# configure the service logging
+#---------------------------------------------------------------------------# 
+
+import logging
+logging.basicConfig()
+log = logging.getLogger()
+log.setLevel(logging.DEBUG)
+
+#---------------------------------------------------------------------------# 
+# create your custom data block here
+#---------------------------------------------------------------------------# 
+
+class CustomDataBlock(ModbusSparseDataBlock):
+    ''' A datablock that stores the new value in memory
+    and performs a custom action after it has been stored.
+    '''
+
+    def setValues(self, address, value):
+        ''' Sets the requested values of the datastore
+
+        :param address: The starting address
+        :param values: The new values to be set
+        '''
+        super(ModbusSparseDataBlock, self).setValues(address, value)
+
+        # whatever you want to do with the written value is done here,
+        # however make sure not to do too much work here or it will
+        # block the server, espectially if the server is being written
+        # to very quickly
+        print "wrote {} to {}".format(value, address)
+
+
+#---------------------------------------------------------------------------# 
+# initialize your data store
+#---------------------------------------------------------------------------# 
+
+block   = CustomDataBlock()
+store   = ModbusSlaveContext(di=block, co=block, hr=block, ir=block)
+context = ModbusServerContext(slaves=store, single=True)
+
+#---------------------------------------------------------------------------# 
+# initialize the server information
+#---------------------------------------------------------------------------# 
+
+identity = ModbusDeviceIdentification()
+identity.VendorName  = 'pymodbus'
+identity.ProductCode = 'PM'
+identity.VendorUrl   = 'http://github.com/bashwork/pymodbus/'
+identity.ProductName = 'pymodbus Server'
+identity.ModelName   = 'pymodbus Server'
+identity.MajorMinorRevision = '1.0'
+
+#---------------------------------------------------------------------------# 
+# run the server you want
+#---------------------------------------------------------------------------# 
+
+p = Process(target=device_writer, args=(queue,))
+p.start()
+StartTcpServer(context, identity=identity, address=("localhost", 5020))

pymodbus/client/sync.py

@@ -197,10 +197,12 @@ def __init__(self, host='127.0.0.1', port=Defaults.Port,
         :param host: The host to connect to (default 127.0.0.1)
         :param port: The modbus port to connect to (default 502)
         :param framer: The modbus framer to use (default ModbusSocketFramer)
+        :param timeout: The timeout to use for this socket (default None)
         '''
-        self.host = host
-        self.port = port
-        self.socket = None
+        self.host    = host
+        self.port    = port
+        self.socket  = None
+        self.timeout = kwargs.get('timeout', None)
         BaseModbusClient.__init__(self, framer(ClientDecoder()), **kwargs)
 
     @classmethod
@@ -226,6 +228,7 @@ def connect(self):
         try:
             family = ModbusUdpClient._get_address_family(self.host)
             self.socket = socket.socket(family, socket.SOCK_DGRAM)
+            self.settimeout(self.timeout)
         except socket.error, ex:
             _logger.error('Unable to create udp socket %s' % ex)
             self.close()