Add read until terminator support for ip instrument

qcodes/instrument/ip.py

@@ -12,6 +12,10 @@ class IPInstrument(Instrument):
     r"""
     Bare socket ethernet instrument implementation.
 
+    Before using the IPInstrument you should strongly consider if you can
+    use Visa over raw sockets connecting to an address in the form:
+    `TCPIP[board]::host address::port::SOCKET`
+
     Args:
         name (str): What this instrument is called locally.
 
@@ -25,6 +29,11 @@ class IPInstrument(Instrument):
 
         terminator (str): Character(s) to terminate each send. Default '\n'.
 
+        read_terminator: Character(s) to look for at the end of each read.
+            Defaults to None in which case only one recv is done
+            Otherwise keeps reading until it gets the termination
+            char(s).
+
         persistent (bool): Whether to leave the socket open between calls.
             Default True.
 
@@ -40,13 +49,16 @@ class IPInstrument(Instrument):
 
     def __init__(self, name, address=None, port=None, timeout=5,
                  terminator='\n', persistent=True, write_confirmation=True,
+                 read_terminator=None,
                  **kwargs):
         super().__init__(name, **kwargs)
 
         self._address = address
         self._port = port
         self._timeout = timeout
         self._terminator = terminator
+        self._read_terminator = read_terminator
+
         self._confirmation = write_confirmation
 
         self._ensure_connection = EnsureConnection(self)
@@ -56,6 +68,22 @@ def __init__(self, name, address=None, port=None, timeout=5,
 
         self.set_persistent(persistent)
 
+    @property
+    def write_terminator(self):
+        return self._terminator
+
+    @write_terminator.setter
+    def write_terminator(self, value):
+        self._terminator = value
+
+    @property
+    def read_terminator(self):
+        return self._read_terminator
+
+    @read_terminator.setter
+    def read_terminator(self, value):
+        self._read_terminator = value
+
     def set_address(self, address=None, port=None):
         """
         Change the IP address and/or port of this instrument.
@@ -142,10 +170,25 @@ def _send(self, cmd):
         self._socket.sendall(data.encode())
 
     def _recv(self):
-        result = self._socket.recv(self._buffer_size)
-        if result == b'':
-            log.warning("Got empty response from Socket recv() "
-                        "Connection broken.")
+        result = b''
+        while True:
+            partresult = self._socket.recv(self._buffer_size)
+            result += partresult
+            if partresult == b'':
+                log.warning("Got empty response from Socket recv() "
+                            "Connection broken.")
+            if self.read_terminator == None:
+                break
+            rtl = len(self.read_terminator)
+            rtloc = result.find(self.read_terminator)
+            if rtloc >= 0:
+                if rtloc + rtl < len(result):
+                    log.warning("Multiple (partial) results received. "
+                                "All but the first result will be discarded. "
+                                "Discarding {}".format(result[rtloc+rtl:]))
+                result = result[0:rtloc]
+                break
+
         return result.decode()
 
     def close(self):
@@ -183,7 +226,7 @@ def ask_raw(self, cmd):
     def __del__(self):
         self.close()
 
-    def snapshot_base(self, update=False):
+    def snapshot_base(self, update=False, params_to_skip_update=None):
         """
         State of the instrument as a JSON-compatible dict.
 
@@ -194,7 +237,8 @@ def snapshot_base(self, update=False):
         Returns:
             dict: base snapshot
         """
-        snap = super().snapshot_base(update=update)
+        snap = super().snapshot_base(update=update,
+                                     params_to_skip_update=params_to_skip_update)
 
         snap['port'] = self._port
         snap['confirmation'] = self._confirmation

qcodes/instrument/ip_to_visa.py

@@ -33,6 +33,7 @@ class up through the chain) and explicitly reimplementing the __init__
 
     def __init__(self, name, address, port, visalib,
                  metadata=None, device_clear=False, terminator='\n',
+                 read_terminator=None,
                  timeout=3, **kwargs):
 
         # remove IPInstrument-specific kwargs

qcodes/instrument_drivers/american_magnetics/AMI430.py

@@ -114,9 +114,11 @@ class AMI430(IPInstrument):
 
     def __init__(self, name, address=None, port=None,
                  reset=False, terminator='\r\n',
+                 read_terminator='\r\n',
                  current_ramp_limit=None, **kwargs):
 
         super().__init__(name, address, port, terminator=terminator,
+                         read_terminator=read_terminator,
                          write_confirmation=False, **kwargs)
         self._parent_instrument = None