Reminders and External Events

The ReminderScheduled event and the trigger_intent endpoint let your assistant remind you about things after a given period of time, or to respond to external events (other applications, sensors, etc.). You can find a full example assistant that implements these features here.

Reminders

Instead of an external sensor, you might just want to be reminded about something after a certain amount of time. For this, Rasa provides the special event ReminderScheduled, and another event, ReminderCancelled, to unschedule a reminder.

Scheduling Reminders

Let’s say you want your assistant to remind you to call a friend in 5 seconds. Thus, we define an intent ask_remind_call with some NLU data,

## intent:ask_remind_call
- remind me to call [Albert](name)
- remind me to call [Susan](name)
- later I have to call [Daksh](name)
- later I have to call [Anna](name)
...

The custom action action_set_reminder should schedule a reminder that, 5 seconds later, triggers an intent EXTERNAL_reminder with all the entities that the user provided in his/her last message:

class ActionSetReminder(Action):
    """Schedules a reminder, supplied with the last message's entities."""
    def name(self) -> Text:
        return "action_set_reminder"
    async def run(self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:
        dispatcher.utter_message("I will remind you in 5 seconds.")
        date = datetime.datetime.now() + datetime.timedelta(seconds=5)
        entities = tracker.latest_message.get("entities")
        reminder = ReminderScheduled(
            "EXTERNAL_reminder",
            trigger_date_time=date,
            entities=entities,
            name="my_reminder",
            kill_on_user_message=False,
        )
        return [reminder]

This requires the datetime and rasa_sdk.events packages.

Finally, we define action_react_to_reminder and link it to the EXTERNAL_reminder intent:

- EXTERNAL_reminder:
  triggers: action_react_to_reminder

Cancelling Reminders

Sometimes the user may want to cancel a reminder that he has scheduled earlier. A simple way of adding this functionality to your assistant is to create an intent ask_forget_reminders:

class ForgetReminders(Action):
    """Cancels all reminders."""
    def name(self) -> Text:
        return "action_forget_reminders"
    async def run(self, dispatcher, tracker: Tracker, domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:
        dispatcher.utter_message(f"Okay, I'll cancel all your reminders.")
        return [ReminderCancelled()]

External Events

Let’s say you want to send a message from some other device to change the course of an ongoing conversation. For example, some moisture-sensor attached to a Raspberry Pi should inform your personal assistant that your favourite plant needs watering.

To do this, your Raspberry Pi needs to send a message to the trigger_intent endpoint of your conversation.

Getting the Conversation ID

You can get the Session ID of the conversation by defining a custom action (see Custom Actions):

class ActionTellID(Action):
    """Informs the user about the conversation ID."""
    def name(self) -> Text:
        return "action_tell_id"
    async def run(self, dispatcher, tracker: Tracker, domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:
        conversation_id = tracker.sender_id
        dispatcher.utter_message(f"The ID of this conversation is: " f"{conversation_id}.")
        return []

Responding to External Events

We need to prepare the assistant so it responds to messages from the sensor. To this end, we define a new intent EXTERNAL_dry_plant:

class ActionWarnDry(Action):
    """Informs the user that a plant needs water."""
    def name(self) -> Text:
        return "action_warn_dry"
    async def run(self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:
        plant = next(tracker.get_latest_entity_values("plant"), "someone")
        dispatcher.utter_message(f"Your {plant} needs some water!")
        return []

Now, running

curl -H "Content-Type: application/json" -X POST -d '{"name": "EXTERNAL_dry_plant", "entities": {"plant": "Orchid"}}' http://localhost:5005/conversations/{conversation_id}/trigger_intent

will cause your assistant to say “Your Orchid needs some water!".