def _create_session(self):
assert self._session is None
col_info = self._active_collector.split(':')
collector = (col_info[0], int(col_info[1]))
self._session = SandeshSession(self._connection.sandesh_instance(),
collector,
self.on_session_event,
self._connection._receive_sandesh_msg)
class SandeshStateMachine(object):
_IDLE_HOLD_TIME = 5 # in seconds
_CONNECT_TIME = 30 # in seconds
def __init__(self, connection, logger, primary_collector,
secondary_collector):
def _update_connection_state(e, status):
from connection_info import ConnectionState
from gen_py.process_info.ttypes import ConnectionType
collector_addr = e.sm._active_collector
if collector_addr is None:
collector_addr = ''
ConnectionState.update(conn_type = ConnectionType.COLLECTOR,
name = '',
status = status,
server_addrs = [collector_addr],
message = '%s to %s on %s' % (e.src, e.dst, e.event))
#end _update_connection_state
def _connection_state_up(e):
from gen_py.process_info.ttypes import ConnectionStatus
_update_connection_state(e, ConnectionStatus.UP)
#end _connection_state_up
def _connection_state_down(e):
from gen_py.process_info.ttypes import ConnectionStatus
_update_connection_state(e, ConnectionStatus.DOWN)
#end _connection_state_down
def _connection_state_init(e):
from gen_py.process_info.ttypes import ConnectionStatus
_update_connection_state(e, ConnectionStatus.INIT)
#end _connection_state_init
def _on_idle(e):
if e.sm._connect_timer is not None:
e.sm._cancel_connect_timer()
# Reset active and backup collector
self._active_collector = self._connection.primary_collector()
self._backup_collector = self._connection.secondary_collector()
# clean up existing connection
e.sm._delete_session()
if e.sm._disable != True:
e.sm._start_idle_hold_timer()
# update connection state
_connection_state_down(e)
#end _on_idle
def _on_disconnect(e):
# update connection state
_connection_state_down(e)
#end _on_disconnect
def _on_connect(e):
if e.sm._idle_hold_timer is not None:
e.sm._cancel_idle_hold_timer()
e.sm._connection.reset_collector()
# clean up existing connection
e.sm._delete_session()
if e.sm._active_collector is not None:
# update connection state
_connection_state_init(e)
e.sm._create_session()
e.sm._start_connect_timer()
e.sm._session.connect()
else:
e.sm.enqueue_event(Event(event = Event._EV_COLLECTOR_UNKNOWN))
#end _on_connect
def _on_connect_to_backup(e):
if e.sm._connect_timer is not None:
e.sm._cancel_connect_timer()
# clean up existing connection
e.sm._delete_session()
# try to connect to the backup collector, if known
if e.sm._backup_collector is not None:
e.sm._active_collector, e.sm._backup_collector = \
e.sm._backup_collector, e.sm._active_collector
# update connection state
_connection_state_init(e)
e.sm._create_session()
e.sm._start_connect_timer()
e.sm._session.connect()
else:
e.sm.enqueue_event(Event(event = Event._EV_BACKUP_COLLECTOR_UNKNOWN))
#end _on_connect_to_backup
def _on_client_init(e):
e.sm._connects += 1
gevent.spawn(e.sm._session.read)
e.sm._connection.handle_initialized(e.sm._connects)
e.sm._connection.sandesh_instance().send_generator_info()
# update connection state
_connection_state_init(e)
#end _on_client_init
def _on_established(e):
e.sm._cancel_connect_timer()
e.sm._connection.set_collector(e.sm_event.source)
e.sm._connection.handle_sandesh_ctrl_msg(e.sm_event.msg)
e.sm._connection.sandesh_instance().send_generator_info()
# update connection state
_connection_state_up(e)
#end _on_established
# FSM - Fysom
self._fsm = Fysom({
'initial': {'state' : State._IDLE,
'event' : Event._EV_START,
'defer' : True
},
'events': [
# _IDLE
{'name' : Event._EV_IDLE_HOLD_TIMER_EXPIRED,
'src' : State._IDLE,
'dst' : State._CONNECT
},
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._IDLE,
'dst' : State._CONNECT
},
{'name' : Event._EV_START,
'src' : State._IDLE,
'dst' : State._CONNECT
},
# _DISCONNECT
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._DISCONNECT,
'dst' : State._CONNECT
},
# _CONNECT
{'name' : Event._EV_COLLECTOR_UNKNOWN,
'src' : State._CONNECT,
'dst' : State._DISCONNECT
},
{'name' : Event._EV_TCP_CONNECT_FAIL,
'src' : State._CONNECT,
'dst' : State._CONNECT_TO_BACKUP
},
{'name' : Event._EV_CONNECT_TIMER_EXPIRED,
'src' : State._CONNECT,
'dst' : State._CONNECT_TO_BACKUP
},
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._CONNECT,
'dst' : State._IDLE
},
{'name' : Event._EV_TCP_CONNECTED,
'src' : State._CONNECT,
'dst' : State._CLIENT_INIT
},
# _CONNECT_TO_BACKUP
{'name' : Event._EV_BACKUP_COLLECTOR_UNKNOWN,
'src' : State._CONNECT_TO_BACKUP,
'dst' : State._IDLE
},
{'name' : Event._EV_TCP_CONNECT_FAIL,
'src' : State._CONNECT_TO_BACKUP,
'dst' : State._IDLE
},
{'name' : Event._EV_CONNECT_TIMER_EXPIRED,
'src' : State._CONNECT_TO_BACKUP,
'dst' : State._IDLE
},
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._CONNECT_TO_BACKUP,
'dst' : State._IDLE
},
{'name' : Event._EV_TCP_CONNECTED,
'src' : State._CONNECT_TO_BACKUP,
'dst' : State._CLIENT_INIT
},
# _CLIENT_INIT
{'name' : Event._EV_CONNECT_TIMER_EXPIRED,
'src' : State._CLIENT_INIT,
'dst' : State._IDLE
},
{'name' : Event._EV_TCP_CLOSE,
'src' : State._CLIENT_INIT,
'dst' : State._IDLE
},
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._CLIENT_INIT,
'dst' : State._IDLE
},
{'name' : Event._EV_SANDESH_CTRL_MESSAGE_RECV,
'src' : State._CLIENT_INIT,
'dst' : State._ESTABLISHED
},
# _ESTABLISHED
{'name' : Event._EV_TCP_CLOSE,
'src' : State._ESTABLISHED,
'dst' : State._CONNECT_TO_BACKUP
},
{'name' : Event._EV_STOP,
'src' : State._ESTABLISHED,
'dst' : State._IDLE
},
{'name' : Event._EV_COLLECTOR_CHANGE,
'src' : State._ESTABLISHED,
'dst' : State._CONNECT
}
],
'callbacks': {
'on' + State._IDLE : _on_idle,
'on' + State._CONNECT : _on_connect,
'on' + State._CONNECT_TO_BACKUP : _on_connect_to_backup,
'on' + State._CLIENT_INIT : _on_client_init,
'on' + State._ESTABLISHED : _on_established,
}
})
self._connection = connection
self._session = None
self._connects = 0
self._disable = False
self._idle_hold_timer = None
self._connect_timer = None
self._active_collector = primary_collector
self._backup_collector = secondary_collector
self._logger = logger
self._event_queue = WorkQueue(self._dequeue_event,
self._is_ready_to_dequeue_event)
#end __init__
# Public functions
def initialize(self):
self.enqueue_event(Event(event = Event._EV_START))
#end initialize
def session(self):
return self._session
#end session
def state(self):
return self._fsm.current
#end state
def shutdown(self):
self._disable = True
self.enqueue_event(Event(event = Event._EV_STOP))
#end shutdown
def set_admin_state(self, down):
if down == True:
self._disable = True
self.enqueue_event(Event(event = Event._EV_STOP))
else:
self._disable = False
self.enqueue_event(Event(event = Event._EV_START))
#end set_admin_state
def connect_count(self):
return self._connects
#end connect_count
def active_collector(self):
return self._active_collector
#end active_collector
def backup_collector(self):
return self._backup_collector
#end backup_collector
def enqueue_event(self, event):
self._event_queue.enqueue(event)
#end enqueue_event
def on_session_event(self, session, event):
if session is not self._session:
self._logger.error("Ignore session event [%d] received for old session" % (event))
return
if SandeshSession.SESSION_ESTABLISHED == event:
self._logger.info("Session Event: TCP Connected")
self.enqueue_event(Event(event = Event._EV_TCP_CONNECTED,
session = session))
elif SandeshSession.SESSION_ERROR == event:
self._logger.error("Session Event: TCP Connect Fail")
self.enqueue_event(Event(event = Event._EV_TCP_CONNECT_FAIL,
session = session))
elif SandeshSession.SESSION_CLOSE == event:
self._logger.error("Session Event: TCP Connection Closed")
self.enqueue_event(Event(event = Event._EV_TCP_CLOSE,
session = session))
else:
self._logger.error("Received unknown session event [%d]" % (event))
#end on_session_event
def on_sandesh_ctrl_msg_receive(self, session, sandesh_ctrl, collector):
if sandesh_ctrl.success == True:
self.enqueue_event(Event(event = Event._EV_SANDESH_CTRL_MESSAGE_RECV,
session = session,
msg = sandesh_ctrl,
source = collector))
else:
# Negotiation with the Collector failed, reset the
# connection and retry after sometime.
self._logger.error("Negotiation with the Collector %s failed." % (collector))
self._session.close()
#end on_sandesh_ctrl_msg_receive
def on_sandesh_uve_msg_send(self, sandesh_uve):
self.enqueue_event(Event(event = Event._EV_SANDESH_UVE_SEND,
msg = sandesh_uve))
#end on_sandesh_uve_msg_send
# Private functions
def _create_session(self):
assert self._session is None
col_info = self._active_collector.split(':')
collector = (col_info[0], int(col_info[1]))
self._session = SandeshSession(self._connection.sandesh_instance(),
collector,
self.on_session_event,
self._connection._receive_sandesh_msg)
#end _create_session
def _delete_session(self):
if self._session:
self._session.close()
self._session = None
self._connection.reset_collector()
#end _delete_session
def _start_idle_hold_timer(self):
if self._idle_hold_timer is None:
if self._IDLE_HOLD_TIME:
self._idle_hold_timer = gevent.spawn_later(self._IDLE_HOLD_TIME,
self._idle_hold_timer_expiry_handler)
else:
self.enqueue_event(Event(event = Event._EV_IDLE_HOLD_TIMER_EXPIRED))
#end _start_idle_hold_timer
def _cancel_idle_hold_timer(self):
if self._idle_hold_timer is not None:
gevent.kill(self._idle_hold_timer)
self._idle_hold_timer = None
#end _cancel_idle_hold_timer
def _idle_hold_timer_expiry_handler(self):
self._idle_hold_timer = None
self.enqueue_event(Event(event = Event._EV_IDLE_HOLD_TIMER_EXPIRED))
#end _idle_hold_timer_expiry_handler
def _start_connect_timer(self):
if self._connect_timer is None:
self._connect_timer = gevent.spawn_later(self._CONNECT_TIME,
self._connect_timer_expiry_handler,
self._session)
#end _start_connect_timer
def _cancel_connect_timer(self):
if self._connect_timer is not None:
gevent.kill(self._connect_timer)
self._connect_timer = None
#end _cancel_connect_timer
def _connect_timer_expiry_handler(self, session):
self._connect_timer = None
self.enqueue_event(Event(event = Event._EV_CONNECT_TIMER_EXPIRED,
session = session))
#end _connect_timer_expiry_handler
def _is_ready_to_dequeue_event(self):
return True
#end _is_ready_to_dequeue_event
def _log_event(self, event):
if self._fsm.current == State._ESTABLISHED and \
event.event == Event._EV_SANDESH_UVE_SEND:
return False
return True
#end _log_event
def _dequeue_event(self, event):
if self._log_event(event):
self._logger.info("Processing event[%s] in state[%s]" \
% (event.event, self._fsm.current))
if event.session is not None and event.session is not self._session:
self._logger.info("Ignore event [%s] received for old session" \
% (event.event))
return
if event.event == Event._EV_COLLECTOR_CHANGE:
old_active_collector = self._active_collector
self._active_collector = event.primary_collector
self._backup_collector = event.secondary_collector
if old_active_collector == self._active_collector:
self._logger.info("No change in active collector. Ignore event [%s]" \
% (event.event))
return
if event.event == Event._EV_SANDESH_UVE_SEND:
if self._fsm.current == State._ESTABLISHED or self._fsm.current == State._CLIENT_INIT:
self._connection.handle_sandesh_uve_msg(event.msg)
else:
self._logger.info("Discarding event[%s] in state[%s]" \
% (event.event, self._fsm.current))
elif event.event == Event._EV_SANDESH_CTRL_MESSAGE_RECV and \
self._fsm.current == State._ESTABLISHED:
self._connection.handle_sandesh_ctrl_msg(event.msg)
elif self._fsm.cannot(event.event) is True:
self._logger.info("Unconsumed event[%s] in state[%s]" \
% (event.event, self._fsm.current))
else:
prev_state = self.state()
getattr(self._fsm, event.event)(sm = self, sm_event = event)
# Log state transition
self._logger.info("Sandesh Client: Event[%s] => State[%s] -> State[%s]" \
% (event.event, prev_state, self.state()))