Support transitions >= 0.5.0

transitions 0.5.0 replaced MachineError with ValueError and
AttributeError for exceptions raised when transitioning the state
machine. MachineError is still available in transitions 0.5.0, so we
catch both MachineError and the relevant new exception to work with
both old and new versions of transitions.

hbmqtt/broker.py

@@ -216,9 +216,10 @@ class Broker:
             self._retained_messages = dict()
             self.transitions.start()
             self.logger.debug("Broker starting")
-        except MachineError as me:
-            self.logger.warn("[WARN-0001] Invalid method call at this moment: %s" % me)
-            raise BrokerException("Broker instance can't be started: %s" % me)
+        except (MachineError, ValueError) as exc:
+            # Backwards compat: MachineError is raised by transitions < 0.5.0.
+            self.logger.warning("[WARN-0001] Invalid method call at this moment: %s" % exc)
+            raise BrokerException("Broker instance can't be started: %s" % exc)
 
         yield from self.plugins_manager.fire_event(EVENT_BROKER_PRE_START)
         try:
@@ -302,9 +303,10 @@ class Broker:
             self._subscriptions = dict()
             self._retained_messages = dict()
             self.transitions.shutdown()
-        except MachineError as me:
-            self.logger.debug("Invalid method call at this moment: %s" % me)
-            raise BrokerException("Broker instance can't be stopped: %s" % me)
+        except (MachineError, ValueError) as exc:
+            # Backwards compat: MachineError is raised by transitions < 0.5.0.
+            self.logger.debug("Invalid method call at this moment: %s" % exc)
+            raise BrokerException("Broker instance can't be stopped: %s" % exc)
 
         # Fire broker_shutdown event to plugins
         yield from self.plugins_manager.fire_event(EVENT_BROKER_PRE_SHUTDOWN)
@@ -393,7 +395,8 @@ class Broker:
             try:
                 client_session.transitions.connect()
                 break
-            except MachineError:
+            except (MachineError, ValueError):
+                # Backwards compat: MachineError is raised by transitions < 0.5.0.
                 self.logger.warning("Client %s is reconnecting too quickly, make it wait" % client_session.client_id)
                 # Wait a bit may be client is reconnecting too fast
                 yield from asyncio.sleep(1, loop=self._loop)

requirements.txt

@@ -1,5 +1,5 @@
-transitions==0.2.5
+transitions
 websockets==3.3.0
 passlib
 docopt
-pyyaml
+pyyaml

setup.py

@@ -17,7 +17,7 @@ setup(
     include_package_data=True,
     platforms='all',
     install_requires=[
-        'transitions==0.2.5',
+        'transitions',
         'websockets',
         'passlib',
         'docopt',