# Rasa SDK

Rasa SDK provides the tools you need to write custom actions in python.

## [Installation](https://legacy-docs-v1.rasa.com/1.9.2/api/rasa-sdk/#installation)

Use `pip` to install `rasa-sdk` on your action server.

```bash
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/1.9.2/api/rasa-sdk/#id3)

If you have `rasa` installed, run this command to start your action server:

```bash
rasa run actions
```

Otherwise, if you do not have `rasa` installed, run this command:

```bash
python -m rasa_sdk --actions actions
```

You can verify that the action server is up and running with the command:

```bash
curl http://localhost:5055/health
```

You can get the list of registered custom actions with the command:

```bash
curl http://localhost:5055/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:

```bash
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/1.9.2/api/rasa-sdk/#id4)

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:

```python
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 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`.

### [Customising the session start action](https://legacy-docs-v1.rasa.com/1.9.2/api/rasa-sdk/#id5)

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:

```python
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]:
        """Collect slots that contain the user's name and phone number."""

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]:

# the session should begin with a `session_started` event
        events = [SessionStarted()]

# any slots that should be carried over should come after the
        # `session_started` event
        events.extend(self.fetch_slots(tracker))

# an `action_listen` should be added at the end as a user message follows
        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/1.9.2/api/rasa-sdk/#id6)

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/1.9.2/api/events/#events). There is an example of a `SlotSet` event
above. 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/1.9.2/api/rasa-sdk/#id7)

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.

#### `Tracker.is_paused()`
State whether the tracker is currently paused.

#### `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. If you are only interested in the first entity of a given type use `next(tracker.get_latest_entity_values("my_entity_name"), None)`. If no entity is found None is the default result.

#### `Tracker.get_latest_input_channel()`
Get the name of the input_channel of the latest UserUttered event

#### `Tracker.events_after_latest_restart()`
Return a list of events after the most recent restart.

#### `Tracker.get_slot(key)`
Retrieves the value of a slot.