Backport Neovi features for release 3.3.4 (#903)

* Use inter-process mutex to prevent concurrent neoVI device open

When neoVI server is enabled, there is an issue with concurrent device open.

* Move neoVI open lock to module level

* Adding dummy file lock when importing FileLock fails

* Grammar fix

* Raising more precise API error when set bitrate fails

Also calling shutdown before raising exception from the init if the device is opened

* Simplified if fd condition in init

* Moving filelock to neovi extras_require

* Adding comma back

* Update CHANGELOG.txt

Co-authored-by: Pierre-Luc Tessier Gagné <[email protected]>

Author: pierreluctg

CHANGELOG.txt

@@ -15,6 +15,7 @@ Version 3.3.3
 
 Backported fixes from 4.x development branch which targets Python 3.
 
+* #846 Use inter-process mutex to prevent concurrent neoVI device open.
 * #798 Backport caching msg.data value in neovi interface.
 * #796 Fix Vector CANlib treatment of empty app name.
 * #771 Handle empty CSV file.

can/interfaces/ics_neovi/neovi_bus.py

@@ -11,6 +11,8 @@
 """
 
 import logging
+import os
+import tempfile
 from collections import deque
 
 from can import Message, CanError, BusABC
@@ -27,6 +29,35 @@
     ics = None
 
 
+try:
+    from filelock import FileLock
+except ImportError as ie:
+
+    logger.warning(
+        "Using ICS NeoVi can backend without the "
+        "filelock module installed may cause some issues!: %s",
+        ie,
+    )
+
+    class FileLock:
+        """Dummy file lock that does not actually do anything"""
+
+        def __init__(self, lock_file, timeout=-1):
+            self._lock_file = lock_file
+            self.timeout = timeout
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, exc_type, exc_val, exc_tb):
+            return None
+
+
+# Use inter-process mutex to prevent concurrent device open.
+# When neoVI server is enabled, there is an issue with concurrent device open.
+open_lock = FileLock(os.path.join(tempfile.gettempdir(), "neovi.lock"))
+
+
 class ICSApiError(CanError):
     """
     Indicates an error with the ICS API.
@@ -118,18 +149,28 @@ def __init__(self, channel, can_filters=None, **kwargs):
         type_filter = kwargs.get('type_filter')
         serial = kwargs.get('serial')
         self.dev = self._find_device(type_filter, serial)
-        ics.open_device(self.dev)
 
-        if 'bitrate' in kwargs:
-            for channel in self.channels:
-                ics.set_bit_rate(self.dev, kwargs.get('bitrate'), channel)
+        with open_lock:
+            ics.open_device(self.dev)
 
-        fd = kwargs.get('fd', False)
-        if fd:
-            if 'data_bitrate' in kwargs:
+        try:
+            if "bitrate" in kwargs:
                 for channel in self.channels:
-                    ics.set_fd_bit_rate(
-                        self.dev, kwargs.get('data_bitrate'), channel)
+                    ics.set_bit_rate(self.dev, kwargs.get("bitrate"), channel)
+
+            if kwargs.get("fd", False):
+                if "data_bitrate" in kwargs:
+                    for channel in self.channels:
+                        ics.set_fd_bit_rate(
+                            self.dev, kwargs.get("data_bitrate"), channel
+                        )
+        except ics.RuntimeError as re:
+            logger.error(re)
+            err = ICSApiError(*ics.get_last_api_error(self.dev))
+            try:
+                self.shutdown()
+            finally:
+                raise err
 
         self._use_system_timestamp = bool(
             kwargs.get('use_system_timestamp', False)

setup.py

@@ -27,7 +27,7 @@
 # Dependencies
 extras_require = {
     'serial':   ['pyserial~=3.0'],
-    'neovi':    ['python-ics>=2.12']
+    'neovi':    ['python-ics>=2.12', 'filelock']
 }
 
 tests_require = [