Select which actions should receive domain#
You can control if an action should receive a domain or not.
To do this you must first enable selective domain in you endpoint configuration for action_endpoint in endpoints.yml.
url: "http://localhost:5055/webhook" # URL to your action server
enable_selective_domain: true
After selective domain for custom actions is enabled, domain will be sent only to those custom actions which have specifically stated that they need it. Custom actions inheriting from rasa-sdk FormValidationAction parent class are an exception to this rule as they will always have the domain sent to them. To specify if an action needs the domain add {send_domain: true} to custom action in the list of actions in domain.yml:
- action_hello_world: {send_domain: True} # will receive domain
- action_calculate_mass_of_sun # will not receive domain
- validate_my_form # will receive domain
Session configuration#
A conversation session represents the dialogue between the assistant and the user. Conversation sessions can begin in three ways:
the user begins the conversation with the assistant,
the user sends their first message after a configurable period of inactivity, or
a manual session start is triggered with the /session_start intent message.
You can define the period of inactivity after which a new conversation session is triggered in the domain under the session_config key.
Available parameters are:
The default session configuration looks as follows:
session_expiration_time: 60 # value in minutes, 0 means infinitely long
carry_over_slots_to_new_session: true # set to false to forget slots between sessions
This means that if a user sends their first message after 60 minutes of inactivity, a new conversation session is triggered, and that any existing slots are carried over into the new session. Setting the value of session_expiration_time to 0 means that sessions will not end (note that the action_session_start action will still be triggered at the very beginning of conversations).
A session start triggers the default action action_session_start. Its default implementation moves all existing slots into the new session. Note that all conversations begin with an action_session_start. Overriding this action could for instance be used to initialize the tracker with slots from an external API call, or to start the conversation with a bot message. The docs on Customizing the session start action shows you how to do that.
The config key in the domain file maintains the store_entities_as_slots parameter. This parameter is used only in the context of reading stories and turning them into trackers. If the parameter is set to True, this will result in slots being implicitly set from entities if applicable entities are present in the story. When an entity matches the from_entity slot mapping, store_entities_as_slots defines whether the entity value should be placed in that slot. Therefore, this parameter skips adding an explicit slot_was_set step manually in the story. By default, this behaviour is switched on.
You can turn off this functionality by setting the store_entities_as_slots parameter to false:
store_entities_as_slots: false
If you're looking for information on the config.yml file, check out the docs on Model Configuration.
A story is a representation of a conversation between a user and an AI assistant, converted into a specific format where user inputs are expressed as intents (and entities when necessary), while the assistant's responses and actions are expressed as action names.
Here's an example of a dialogue in the Rasa story format:
- story: collect restaurant booking info # name of the story - just for debugging
- intent: greet # user message with no entities
- action: utter_ask_howcanhelp
- intent: inform # user message with entities
- action: utter_on_it # action that the bot should execute
- action: utter_ask_cuisine
- action: utter_ask_num_people
While writing stories, you do not have to deal with the specific contents of the messages that the users send. Instead, you can take advantage of the output from the NLU pipeline, which lets you use just the combination of an intent and entities to refer to all the possible messages the users can send to mean the same thing.
It is important to include the entities here as well because the policies learn to predict the next action based on a combination of both the intent and entities (you can, however, change this behavior using the use_entities attribute).
All actions executed by the bot, including responses are listed in stories under the action key.
You can use a response from your domain as an action by listing it as one in a story. Similarly, you can indicate that a story should call a custom action by including the name of the custom action from the actions list in your domain.
During training, Rasa does not call the action server. This means that your assistant's dialogue management model doesn't know which events a custom action will return.
Because of this, events such as setting a slot or activating/deactivating a form have to be explicitly written out as part of the stories. For more info, see the documentation on Events.
Slot events are written under slot_was_set in a story. If this slot is set inside a custom action, add the slot_was_set event immediately following the custom action call. If your custom action resets a slot value to None, the corresponding event for that would look like this:
- story: set slot to none
# ... other story steps
- action: my_custom_action
There are three kinds of events that need to be kept in mind while dealing with forms in stories.
A form action event (e.g. - action: restaurant_form) is used in the beginning when first starting a form, and also while resuming the form action when the form is already active.
A form activation event (e.g. - active_loop: restaurant_form) is used right after the first form action event.
A form deactivation event (e.g. - active_loop: null), which is used to deactivate the form.
In order to get around the pitfall of forgetting to add events, the recommended way to write these stories is to use interactive learning.
Multiple Domain Files#
The domain can be defined as a single YAML file or split across multiple files in a directory. When split across multiple files, the domain contents will be read and automatically merged together.
Using the command line interface, you can train a model with split domain files by running:
rasa train --domain path_to_domain_directory
The intents key in your domain file lists all intents used in your NLU data and conversation training data.
Head Office Planetmoto
The Belleza Office Tower Lt. 7 Unit 1
Jln. Letjen Soepono No. 34, Arteri Permata Hijau
Grogol Utara, Kebayoran Lama, Jakarta Selatan
In Rasa, your domain defines the universe in which your assistant operates. Specifically, it lists:
If you are building an NLU-based assistant, refer to the Domain documentation to see how intents, entities, slot mappings, and slot featurization can be configured in your domain.
Validating Form Input#
After extracting a slot value from user input, you can validate the extracted slots. By default Rasa Open Source only validates if any slot was filled after requesting a slot.
Forms no longer raise ActionExecutionRejection if nothing is extracted from the user’s utterance for any of the required slots.
You can implement a Custom Action validate_
- validate_restaurant_form
When the form is executed it will run your custom action.
This custom action can extend FormValidationAction class to simplify
the process of validating extracted slots. In this case, you need to write functions
named validate_
The following example shows the implementation of a custom action which validates that the slot named cuisine is valid.
from typing import Text, List, Any, Dict
from rasa_sdk import Tracker, FormValidationAction
from rasa_sdk.executor import CollectingDispatcher
from rasa_sdk.types import DomainDict
class ValidateRestaurantForm(FormValidationAction):
def name(self) -> Text:
return "validate_restaurant_form"
def cuisine_db() -> List[Text]:
"""Database of supported cuisines"""
return ["caribbean", "chinese", "french"]
def validate_cuisine(
dispatcher: CollectingDispatcher,
) -> Dict[Text, Any]:
"""Validate cuisine value."""
if slot_value.lower() in self.cuisine_db():
return {"cuisine": slot_value}
return {"cuisine": None}
You can also extend the Action class and retrieve extracted slots with tracker.slots_to_validate to fully customize the validation process.
Checkpoints and OR statements#
Checkpoints and OR statements should be used with caution, if at all. There is usually a better way to achieve what you want by using Rules or the ResponseSelector.
You can use checkpoints to modularize and simplify your training data. Checkpoints can be useful, but do not overuse them. Using lots of checkpoints can quickly make your example stories hard to understand, and will slow down training.
Here is an example of stories that contain checkpoints:
- story: beginning of flow
- action: action_ask_user_question
- checkpoint: check_asked_question
- story: handle user affirm
- checkpoint: check_asked_question
- action: action_handle_affirmation
- checkpoint: check_flow_finished
- story: handle user deny
- checkpoint: check_asked_question
- action: action_handle_denial
- checkpoint: check_flow_finished
- checkpoint: check_flow_finished
- action: utter_goodbye
Unlike regular stories, checkpoints are not restricted to starting with user input. As long as the checkpoint is inserted at the right points in the main stories, the first event can be a custom action or a response as well.
Another way to write shorter stories, or to handle multiple intents or slot events the same way, is to use an or statement. For example, if you ask the user to confirm something, and you want to treat the affirm and thankyou intents in the same way. The story below will be converted into two stories at training time:
- action: utter_ask_confirm
- action: action_handle_affirmation
You can also use or statements with slot events. The following means the story requires that the current value for the name slot is set and is either joe or bob:
- action: utter_greet
or statements can be useful, but if you are using a lot of them, it is probably better to restructure your domain and/or intents. Overusing OR statements will slow down training.
Using a Custom Action to Ask For the Next Slot#
As soon as the form determines which slot has to be filled next by the user, it will
execute the action utter_ask_
from typing import Dict, Text, List
from rasa_sdk import Tracker
from rasa_sdk.events import EventType
from rasa_sdk.executor import CollectingDispatcher
from rasa_sdk import Action
class AskForSlotAction(Action):
def name(self) -> Text:
return "action_ask_cuisine"
self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict
) -> List[EventType]:
dispatcher.utter_message(text="What cuisine?")
If there is more than one asking option for the slot, Rasa prioritizes in the following order:
Channel-Specific Response Variations#
To specify different response variations depending on which channel the user is connected to, use channel-specific response variations.
In the following example, the channel key makes the first response variation channel-specific for the slack channel while the second variation is not channel-specific:
- text: "Which game would you like to play on Slack?"
- text: "Which game would you like to play?"
Make sure the value of the channel key matches the value returned by the name() method of your input channel. If you are using a built-in channel, this value will also match the channel name used in your credentials.yml file.
When your assistant looks for suitable response variations under a given response name, it will first try to choose from channel-specific variations for the current channel. If there are no such variations, the assistant will choose from any response variations which are not channel-specific.
In the above example, the second response variation has no channel specified and can be used by your assistant for all channels other than slack.
For each response, try to have at least one response variation without the channel key. This allows your assistant to properly respond in all environments, such as in new channels, in the shell and in interactive learning.
The requested_slot slot#
The slot requested_slot is automatically added to the domain as a slot of type text. The value of the requested_slot will be ignored during conversations. If you want to change this behavior, you need to add the requested_slot to your domain file as a categorical slot with influence_conversation set to true. You might want to do this if you want to handle your unhappy paths differently, depending on what slot is currently being asked from the user. For example, if your users respond to one of the bot's questions with another question, like why do you need to know that? The response to this explain intent depends on where we are in the story. In the restaurant case, your stories would look something like this:
- story: explain cuisine slot
- intent: request_restaurant
- action: restaurant_form
- active_loop: restaurant
- requested_slot: cuisine
- action: utter_explain_cuisine
- action: restaurant_form
- story: explain num_people slot
- intent: request_restaurant
- action: restaurant_form
- active_loop: restaurant
- requested_slot: cuisine
- requested_slot: num_people
- action: utter_explain_num_people
- action: restaurant_form
Again, it is strongly recommended that you use interactive learning to build these stories.
Dynamic Form Behavior#
By default Rasa Open Source will ask for the next empty slot from the slots listed for your form in the domain file. If you use custom slot mappings and the FormValidationAction, it will ask for the first empty slot returned by the required_slots method. If all slots in required_slots are filled the form will be be deactivated.
If needed, you can update the required slots of your form dynamically. This is, for example, useful when you need further details based on how a previous slot was filled or you want to change the order in which slots are requested.
If you are using the Rasa SDK, we recommend you to use the FormValidationAction and
override required_slots to fit your dynamic behavior. You should implement
a method extract_
from typing import Text, List, Optional
from rasa_sdk.forms import FormValidationAction
class ValidateRestaurantForm(FormValidationAction):
def name(self) -> Text:
return "validate_restaurant_form"
async def required_slots(
slots_mapped_in_domain: List[Text],
dispatcher: "CollectingDispatcher",
domain: "DomainDict",
) -> Optional[List[Text]]:
additional_slots = ["outdoor_seating"]
if tracker.slots.get("outdoor_seating") is True:
additional_slots.append("shade_or_sun")
return additional_slots + slots_mapped_in_domain
