[datalistener ]improve log message when port is occupy

orangecontrib/tomwer/widgets/control/DataListenerOW.py

@@ -125,6 +125,25 @@ class DataListenerOW(widget.OWWidget, OWClient, WidgetLongProcessing,
 
     @docstring(DataListener.activate)
     def activate(self, activate=True):
+        if activate and not self.is_port_available():
+            old = self._widget.blockSignals(True)
+            self._widget.activate(activate=False)
+            self._widget.blockSignals(old)
+            err = (
+                "port ({port}) of {host} already in use. Maybe an "
+                'other instance of "datalistener" is running in this '
+                "session or another tomwer session. As this widget is "
+                "connecting with bliss we enforce it to be unique. "
+                "If necessary you can hard kill server process ()"
+                "".format(port=self.port, host=self.host)
+            )
+            logger.warning(err)
+            mess = qt.QMessageBox(self, qt.QMessageBox.Warning, err)
+            mess.setModal(False)
+            mess.setWindowTitle("Unable to launch two listener in parallel")
+            mess.show()
+            return
+
         old = self._widget.blockSignals(True)
         self.set_configuration(self._widget.getBlissServerConfiguration())
         self._widget.activate(activate=activate)

tomwer/core/process/datalistener/datalistener.py

@@ -28,7 +28,7 @@ __license__ = "MIT"
 __date__ = "05/07/2017"
 
 
-import h5py
+import socket
 import os
 from tomwer.core import settings
 import tomwer.version
@@ -82,7 +82,6 @@ class DataListener(SingleProcess):
         self._host = settings.JSON_RPC_HOST
         # if host is None then use hostname
         if self._host is None:
-            import socket
             self._host = socket.gethostname()
         self._port = settings.JSON_RPC_PORT
         self._listening_thread = None
@@ -104,11 +103,11 @@ class DataListener(SingleProcess):
 
     @property
     def port(self):
-        return self.port
+        return self._port
 
     @property
     def host(self):
-        return self.host
+        return self._host
 
     def get_listening_thread(self):
         """
@@ -472,6 +471,8 @@ class DataListener(SingleProcess):
                 _logger.info('listening is already activate')
             else:
                 assert isinstance(self, DataListener)
+                if not self.is_port_available():
+                    raise OSError("Port already used")
                 self.get_listening_thread().start()
         else:
             if self._listening_thread is None:
@@ -484,3 +485,11 @@ class DataListener(SingleProcess):
             return False
         else:
             return True
+
+    def is_port_available(self):
+        """
+
+        :return: True if the port is available else False
+        """
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            return not s.connect_ex((self._host, self._port)) == 0

tomwer/core/process/datalistener/rpcserver.py

@@ -36,6 +36,7 @@ from multiprocessing import Process
 from werkzeug.wrappers import Request, Response
 from werkzeug.serving import run_simple
 from jsonrpc import JSONRPCResponseManager, dispatcher
+import socket
 
 
 _logger = logging.getLogger(__name__)
@@ -134,7 +135,6 @@ class _BaseDataListenerThread:
         self._host = host
         # if host is None then use hostname
         if self._host is None:
-            import socket
             self._host = socket.gethostname()
         self._port = port
         self._tomo_state = None

tomwer/gui/control/datalistener.py

@@ -30,6 +30,7 @@ __date__ = "16/03/2020"
 
 import os
 import weakref
+import socket
 from silx.gui import qt
 from tomwer.core import settings
 from tomwer.core.process.utils import LastReceivedScansDict
@@ -374,7 +375,6 @@ class ConfigurationWidget(qt.QDialog):
         # set up
         self._buttons.hide()
         if settings.JSON_RPC_HOST is None:
-            import socket
             self.setHost(socket.gethostname())
         else:
             self.setHost(settings.JSON_RPC_HOST)