Introduction to Slots

In this lesson we will show you how to configure slots to store information on the long term.

Video#

Code#

If you want to use slots to store information for the long term in Rasa you first need to make your domain.yml file aware of the slots. Here's what we added in our video.

slots:
  name:
    type: text

Note that if you want to run these custom actions you'll need to make sure that your endpoints.yml file is properly configured.

action_endpoint:
    url: "http://localhost:5055/webhook"

Next, we're using custom actions to interact with this slot. We've defined these in our actions/actions.py file.

from typing import Any, Text, Dict, List

from rasa_sdk.events import SlotSet
from rasa_sdk import Action, Tracker
from rasa_sdk.executor import CollectingDispatcher


class ActionReceiveName(Action):

    def name(self) -> Text:
        return "action_receive_name"

    def run(self, dispatcher: CollectingDispatcher,
            tracker: Tracker,
            domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:

        text = tracker.latest_message['text']
        dispatcher.utter_message(text=f"I'll remember your name {text}!")
        return [SlotSet("name", text)]


class ActionSayName(Action):

    def name(self) -> Text:
        return "action_say_name"

    def run(self, dispatcher: CollectingDispatcher,
            tracker: Tracker,
            domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:

        name = tracker.get_slot("name")
        if not name:
            dispatcher.utter_message(text="I don't know your name.")
        else:
            dispatcher.utter_message(text=f"Your name is {name}!")
        return []

Assuming the action server is running and that you've updated your nlu/stories/domain file you should be able to interact with your custom action from the rasa shell now.

rasa shell

Interactive#

If you run rasa interactive you'll be able to see the state of the slots while the conversation is happening. When you decide to save the results you may see a new part in your stories.yml file like below.

- story: interactive_story_1
  steps:
  - intent: greet
  - action: utter_greet
  - intent: tell_name
  - action: utter_ask_name
  - intent: give_name
  - action: action_receive_name
  - slot_was_set:
    - name: vincent
  - intent: repeat_name
  - action: action_say_name
  - intent: tell_name
  - action: utter_ask_name
  - intent: give_name
  - action: action_receive_name
  - slot_was_set:
    - name: jenny
  - intent: repeat_name
  - action: action_say_name
  - intent: goodbye
  - action: utter_goodbye

Links#

• GitHub repo
• Rasa Open Source Docs

Exercises#

Try to answer the following questions to test your knowledge.

1. In what file do you need to define your slots?
2. What is the name of the event in the custom action that can set the slot?