From a6b7fa04ab0dea2e2fe70d66b49006aeb795e502 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Krist=C3=B3f=20T=C3=B3th?= <kristof.toth@avatao.com>
Date: Tue, 24 Jul 2018 17:16:57 +0200
Subject: [PATCH] Rework fsm_update API

---
 .../components/fsm_managing_event_handler.py  | 21 ++++++++++---------
 lib/tfw/event_handler_base.py                 | 11 +++++-----
 lib/tfw/fsm/fsm_base.py                       | 18 ++++++++++++++--
 3 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/lib/tfw/components/fsm_managing_event_handler.py b/lib/tfw/components/fsm_managing_event_handler.py
index 47761a0..39ec3ae 100644
--- a/lib/tfw/components/fsm_managing_event_handler.py
+++ b/lib/tfw/components/fsm_managing_event_handler.py
@@ -25,7 +25,7 @@ class FSMManagingEventHandler(EventHandlerBase):
         try:
             message = self.command_handlers[message['data']['command']](message)
             if message:
-                fsm_update_message = self._fsm_updater.generate_fsm_update()
+                fsm_update_message = self._fsm_updater.fsm_update
                 sign_message(self.auth_key, message)
                 sign_message(self.auth_key, fsm_update_message)
                 self.server_connector.broadcast(fsm_update_message)
@@ -52,23 +52,24 @@ class FSMUpdater:
     def __init__(self, fsm):
         self.fsm = fsm
 
-    def generate_fsm_update(self):
+    @property
+    def fsm_update(self):
         return {
             'key': 'fsm_update',
-            'data': self.get_fsm_state_and_transitions()
+            'data': self.fsm_update_data
         }
 
-    def get_fsm_state_and_transitions(self):
-        state = self.fsm.state
+    @property
+    def fsm_update_data(self):
         valid_transitions = [
             {'trigger': trigger}
             for trigger in self.fsm.get_triggers(self.fsm.state)
         ]
-        last_trigger = self.fsm.trigger_history[-1] if self.fsm.trigger_history else None
-        in_accepted_state = state in self.fsm.accepted_states
+        last_fsm_event = self.fsm.event_log[-1]
+        last_fsm_event['timestamp'] = last_fsm_event['timestamp'].isoformat()
         return {
-            'current_state': state,
+            'current_state': self.fsm.state,
             'valid_transitions': valid_transitions,
-            'last_trigger': last_trigger,
-            'in_accepted_state': in_accepted_state
+            'in_accepted_state': self.fsm.in_accepted_state,
+            'last_event': last_fsm_event
         }
diff --git a/lib/tfw/event_handler_base.py b/lib/tfw/event_handler_base.py
index de170f0..4c7ad06 100644
--- a/lib/tfw/event_handler_base.py
+++ b/lib/tfw/event_handler_base.py
@@ -109,7 +109,7 @@ class EventHandlerBase(ABC):
 class FSMAware:
     def __init__(self):
         self.fsm_state = None
-        self.in_accepted_state = False
+        self.fsm_in_accepted_state = False
         self._auth_key = KeyManager().auth_key
 
     def update_fsm_data(self, message):
@@ -121,17 +121,18 @@ class FSMAware:
     def _handle_fsm_update(self, message):
         try:
             new_state = message['data']['current_state']
-            trigger = message['data']['last_trigger']
             if self.fsm_state != new_state:
-                self.handle_fsm_step(self.fsm_state, new_state, trigger)
+                self.handle_fsm_step(**(message['data']))
             self.fsm_state = new_state
-            self.in_accepted_state = message['data']['in_accepted_state']
+            self.fsm_in_accepted_state = message['data']['in_accepted_state']
         except KeyError:
             LOG.error('Invalid fsm_update message received!')
 
-    def handle_fsm_step(self, from_state, to_state, trigger):
+    def handle_fsm_step(self, **kwargs):
         """
         Called in case the TFW FSM has stepped.
+
+        :param kwargs: fsm_update 'data' field
         """
         pass
 
diff --git a/lib/tfw/fsm/fsm_base.py b/lib/tfw/fsm/fsm_base.py
index 7ae8157..e33ae33 100644
--- a/lib/tfw/fsm/fsm_base.py
+++ b/lib/tfw/fsm/fsm_base.py
@@ -2,6 +2,7 @@
 # All Rights Reserved. See LICENSE file for details.
 
 from collections import defaultdict
+from datetime import datetime
 
 from transitions import Machine, MachineError
 
@@ -24,7 +25,7 @@ class FSMBase(Machine, CallbackMixin):
     def __init__(self, initial=None, accepted_states=None):
         self.accepted_states = accepted_states or [self.states[-1].name]
         self.trigger_predicates = defaultdict(list)
-        self.trigger_history = []
+        self.event_log = []
 
         Machine.__init__(
             self,
@@ -60,9 +61,22 @@ class FSMBase(Machine, CallbackMixin):
 
         if all(predicate_results):
             try:
+                from_state = self.state
                 self.trigger(trigger)
-                self.trigger_history.append(trigger)
+                self.update_event_log(from_state, trigger)
                 return True
             except (AttributeError, MachineError):
                 LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)
         return False
+
+    def update_event_log(self, from_state, trigger):
+        self.event_log.append({
+            'from_state': from_state,
+            'to_state': self.state,
+            'trigger': trigger,
+            'timestamp': datetime.utcnow()
+        })
+
+    @property
+    def in_accepted_state(self):
+        return self.state in self.accepted_states