# Rasa SDK Rasa SDK provides the tools you need to write custom actions in python. ## [Installation](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#installation) Use `pip` to install `rasa-sdk` on your action server. ``` pip install rasa-sdk ``` Note You do not need to install `rasa` for your action server. E.g. if you are running Rasa in a docker container, it is recommended to create a separate container for your action server. In this separate container, you only need to install `rasa-sdk`. ## [Running the Action Server](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#running-the-action-server) If you have `rasa` installed, run this command to start your action server: ``` rasa run actions ``` Otherwise, if you do not have `rasa` installed, run this command: ``` python -m rasa_sdk --actions actions ``` The file that contains your custom actions should be called `actions.py`. Alternatively, you can use a package directory called `actions` or else manually specify an actions module or package with the `--actions` flag. The full list of options for running the action server with either command is: ``` usage: rasa run actions [-h] [-v] [-vv] [--quiet] [-p PORT] [--cors [CORS [CORS ...]]] [--actions ACTIONS] [--ssl-keyfile SSL_KEYFILE] [--ssl-certificate SSL_CERTIFICATE] [--ssl-password SSL_PASSWORD] [--auto-reload] optional arguments: -h, --help show this help message and exit -p PORT, --port PORT port to run the server at (default: 5055) --cors [CORS [CORS ...]] enable CORS for the passed origin. Use * to whitelist all origins (default: None) --actions ACTIONS name of action package to be loaded (default: None) --ssl-keyfile SSL_KEYFILE Set the SSL certificate to create a TLS secured server. (default: None) --ssl-certificate SSL_CERTIFICATE Set the SSL certificate to create a TLS secured server. (default: None) --ssl-password SSL_PASSWORD If your ssl-keyfile is protected by a password, you can specify it using this paramer. (default: None) --auto-reload Enable auto-reloading of modules containing Action subclasses. (default: False) Python Logging Options: -v, --verbose Be verbose. Sets logging level to INFO. (default: None) -vv, --debug Print lots of debugging statements. Sets logging level to DEBUG. (default: None) --quiet Be quiet! Sets logging level to WARNING. (default: None) ``` ## [Actions](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#actions) The `Action` class is the base class for any custom action. It has two methods that both need to be overwritten, `name()` and `run()`. In a restaurant bot, if the user says “show me a Mexican restaurant”, your bot could execute the action `ActionCheckRestaurants`, which might look like this: ``` from rasa_sdk import Action from rasa_sdk.events import SlotSet class ActionCheckRestaurants(Action): def name(self) -> Text: return "action_check_restaurants" def run(self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict[Text, Any]) -> List[Dict[Text, Any]]: cuisine = tracker.get_slot('cuisine') q = "select * from restaurants where cuisine='{0}' limit 1".format(cuisine) result = db.query(q) return [SlotSet("matches", result if result is not None else [])] ``` You should add the the action name `action_check_restaurants` to the actions in your domain file. The action’s `run()` method receives three arguments. You can access the values of slots and the latest message sent by the user using the `tracker` object, and you can send messages back to the user with the `dispatcher` object, by calling `dispatcher.utter_message`. Details of the `run()` method: `async Action.run(dispatcher, tracker, domain)` Execute the side effects of this action. Parameters - **dispatcher** – the dispatcher which is used to send messages back to the user. Use `dipatcher.utter_message()` or any other `rasa_sdk.executor.CollectingDispatcher` method. - **tracker** – the state tracker for the current user. You can access slot values using `tracker.get_slot(slot_name)`, the most recent user message is `tracker.latest_message.text` and any other `rasa_sdk.Tracker` property. - **domain** – the bot’s domain Returns A dictionary of `rasa_sdk.events.Event` instances that is returned through the endpoint Return type `List[Dict[str, Any]]` Details of the `dispatcher.utter_message()` method: `CollectingDispatcher.utter_message(text=None, image=None, json_message=None, template=None, attachment=None, buttons=None, elements=None, **kwargs)` “Send a text to the output channel Return type `None` ### [Customising the session start action](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#customising-the-session-start-action) The default behaviour of the session start action is to take all existing slots and to carry them over into the next session. Let’s say you do not want to carry over all slots, but only a user’s name and their phone number. To do that, you’d override the `action_session_start` with a custom action that might look like this: ``` from typing import Text, List, Dict, Any from rasa_sdk import Action, Tracker from rasa_sdk.events import SlotSet, SessionStarted, ActionExecuted, EventType from rasa_sdk.executor import CollectingDispatcher class ActionSessionStart(Action): def name(self) -> Text: return "action_session_start" @staticmethod def fetch_slots(tracker: Tracker) -> List[EventType]: slots = [] for key in ("name", "phone_number"): value = tracker.get_slot(key) if value is not None: slots.append(SlotSet(key=key, value=value)) return slots async def run( self, dispatcher: CollectingDispatcher, tracker: Tracker, domain: Dict[Text, Any], ) -> List[EventType]: events = [SessionStarted()] events.extend(self.fetch_slots(tracker)) events.append(ActionExecuted("action_listen")) return events ``` Note You need to explicitly add `action_session_start` to your domain to override this custom action. ## [Events](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#events) An action’s `run()` method returns a list of events. For more information on the different types of events, see [Events](https://legacy-docs-v1.rasa.com/1.6.2/api/events/#events). There is an example of a `SlotSet` event [above](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#custom-action-example). The action itself will automatically be added to the tracker as an `ActionExecuted` event. If the action should not trigger any other events, it should return an empty list. ## [Tracker](https://legacy-docs-v1.rasa.com/1.6.2/api/rasa-sdk/#tracker) The `rasa_sdk.Tracker` lets you access the bot’s memory in your custom actions. You can get information about past events and the current state of the conversation through `Tracker` attributes and methods. The following are available as attributes of a `Tracker` object: - `sender_id` - The unique ID of person talking to the bot. - `slots` - The list of slots that can be filled as defined in the “ref” domains. - `latest_message` - A dictionary containing the attributes of the latest message: `intent`, `entities` and `text`. - `events` - A list of all previous events. - `active_form` - The name of the currently active form. - `latest_action_name` - The name of the last action the bot executed. The available methods from the `Tracker` are: `Tracker.current_state()` Return the current tracker state as an object. Return type `Dict[str, Any]` `Tracker.is_paused()` State whether the tracker is currently paused. Return type `bool` `Tracker.get_latest_entity_values(entity_type, entity_role=None, entity_group=None)` Get entity values found for the passed entity type and optional role and group in latest message. Returns List of entity values. Return type `Iterator[str]` `Tracker.get_latest_input_channel()` Get the name of the input_channel of the latest UserUttered event Return type `Optional[str]` `Tracker.events_after_latest_restart()` Return a list of events after the most recent restart. Return type `List[dict]` `Tracker.get_slot(key)` Retrieves the value of a slot. Return type `Optional[Any]` 👋 I can help you get started with Rasa and answer your technical questions.