start event is called everytime a new step starts. So a new value for "active_brew" will only be generated if the value before was "none". The value is "none" either after initializing the app or after the process got stopped. That leaves one potentiall error: if a process is started and the app needs a restart. In this case a new value for "active_brew" would be unecessarily generated.

modules/steps/__init__.py

@@ -146,7 +146,8 @@ class StepView(BaseView):
 
     @route('/start', methods=['POST'])
     def start(self):
-        cbpi.cache["active_brew"] = cbpi.cache["config"]["brew_name"].__dict__["value"] + \
+        if "none" == cbpi.cache["active_brew"]:
+            cbpi.cache["active_brew"] = cbpi.cache["config"]["brew_name"].__dict__["value"] + \
                                     "_" + datetime.datetime.now().strftime('%y-%m-%dT%H:%M')
         return self.next()