notice

This is documentation for Rasa Documentation v2.x, which is no longer actively maintained.
For up-to-date documentation, see the latest version (3.x).

Version: 2.x

rasa.core.tracker_store

TrackerStore Objects

class TrackerStore()

Represents common behavior and interface for all TrackerStores.

__init__

| __init__(domain: Optional[Domain], event_broker: Optional[EventBroker] = None, **kwargs: Dict[Text, Any], ,) -> None

Create a TrackerStore.

Arguments:

  • domain - The Domain to initialize the DialogueStateTracker.
  • event_broker - An event broker to publish any new events to another destination.
  • kwargs - Additional kwargs.

create

| @staticmethod
| create(obj: Union["TrackerStore", EndpointConfig, None], domain: Optional[Domain] = None, event_broker: Optional[EventBroker] = None) -> "TrackerStore"

Factory to create a tracker store.

get_or_create_tracker

| get_or_create_tracker(sender_id: Text, max_event_history: Optional[int] = None, append_action_listen: bool = True) -> "DialogueStateTracker"

Returns tracker or creates one if the retrieval returns None.

Arguments:

  • sender_id - Conversation ID associated with the requested tracker.
  • max_event_history - Value to update the tracker store's max event history to.
  • append_action_listen - Whether or not to append an initial action_listen.

init_tracker

| init_tracker(sender_id: Text) -> "DialogueStateTracker"

Returns a Dialogue State Tracker

create_tracker

| create_tracker(sender_id: Text, append_action_listen: bool = True) -> DialogueStateTracker

Creates a new tracker for sender_id.

The tracker begins with a SessionStarted event and is initially listening.

Arguments:

  • sender_id - Conversation ID associated with the tracker.
  • append_action_listen - Whether or not to append an initial action_listen.

Returns:

The newly created tracker for sender_id.

save

| save(tracker: DialogueStateTracker) -> None

Save method that will be overridden by specific tracker.

exists

| exists(conversation_id: Text) -> bool

Checks if tracker exists for the specified ID.

This method may be overridden by the specific tracker store for faster implementations.

Arguments:

  • conversation_id - Conversation ID to check if the tracker exists.

Returns:

True if the tracker exists, False otherwise.

retrieve

| retrieve(sender_id: Text) -> Optional[DialogueStateTracker]

Retrieves tracker for the latest conversation session.

This method will be overridden by the specific tracker store.

Arguments:

  • sender_id - Conversation ID to fetch the tracker for.

Returns:

Tracker containing events from the latest conversation sessions.

retrieve_full_tracker

| retrieve_full_tracker(conversation_id: Text) -> Optional[DialogueStateTracker]

Retrieve method for fetching all tracker events across conversation sessions that may be overridden by specific tracker.

The default implementation uses self.retrieve().

Arguments:

  • conversation_id - The conversation ID to retrieve the tracker for.

Returns:

The fetch tracker containing all events across session starts.

stream_events

| stream_events(tracker: DialogueStateTracker) -> None

Streams events to a message broker

number_of_existing_events

| number_of_existing_events(sender_id: Text) -> int

Return number of stored events for a given sender id.

keys

| keys() -> Iterable[Text]

Returns the set of values for the tracker store's primary key

serialise_tracker

| @staticmethod
| serialise_tracker(tracker: DialogueStateTracker) -> Text

Serializes the tracker, returns representation of the tracker.

deserialise_tracker

| deserialise_tracker(sender_id: Text, serialised_tracker: Union[Text, bytes]) -> Optional[DialogueStateTracker]

Deserializes the tracker and returns it.

InMemoryTrackerStore Objects

class InMemoryTrackerStore(TrackerStore)

Stores conversation history in memory

save

| save(tracker: DialogueStateTracker) -> None

Updates and saves the current conversation state

keys

| keys() -> Iterable[Text]

Returns sender_ids of the Tracker Store in memory

RedisTrackerStore Objects

class RedisTrackerStore(TrackerStore)

Stores conversation history in Redis

save

| save(tracker: DialogueStateTracker, timeout: Optional[float] = None) -> None

Saves the current conversation state.

retrieve

| retrieve(sender_id: Text) -> Optional[DialogueStateTracker]

Retrieves tracker for the latest conversation session.

The Redis key is formed by appending a prefix to sender_id.

Arguments:

  • sender_id - Conversation ID to fetch the tracker for.

Returns:

Tracker containing events from the latest conversation sessions.

keys

| keys() -> Iterable[Text]

Returns keys of the Redis Tracker Store.

DynamoTrackerStore Objects

class DynamoTrackerStore(TrackerStore)

Stores conversation history in DynamoDB

__init__

| __init__(domain: Domain, table_name: Text = "states", region: Text = "us-east-1", event_broker: Optional[EndpointConfig] = None, **kwargs: Dict[Text, Any], ,) -> None

Initialize DynamoTrackerStore.

Arguments:

  • domain - Domain associated with this tracker store.
  • table_name - The name of the DynamoDB table, does not need to be present a priori.
  • region - The name of the region associated with the client. A client is associated with a single region.
  • event_broker - An event broker used to publish events.
  • kwargs - Additional kwargs.

get_or_create_table

| get_or_create_table(table_name: Text) -> "boto3.resources.factory.dynamodb.Table"

Returns table or creates one if the table name is not in the table list.

save

| save(tracker: DialogueStateTracker) -> None

Saves the current conversation state.

serialise_tracker

| serialise_tracker(tracker: "DialogueStateTracker") -> Dict

Serializes the tracker, returns object with decimal types.

keys

| keys() -> Iterable[Text]

Returns sender_ids of the DynamoTrackerStore.

MongoTrackerStore Objects

class MongoTrackerStore(TrackerStore)

Stores conversation history in Mongo.

Property methods: conversations: returns the current conversation

conversations

| @property
| conversations() -> Collection

Returns the current conversation.

save

| save(tracker: DialogueStateTracker) -> None

Saves the current conversation state.

keys

| keys() -> Iterable[Text]

Returns sender_ids of the Mongo Tracker Store.

is_postgresql_url

is_postgresql_url(url: Union[Text, "URL"]) -> bool

Determine whether url configures a PostgreSQL connection.

Arguments:

  • url - SQL connection URL.

Returns:

True if url is a PostgreSQL connection URL.

create_engine_kwargs

create_engine_kwargs(url: Union[Text, "URL"]) -> Dict[Text, Any]

Get sqlalchemy.create_engine() kwargs.

Arguments:

  • url - SQL connection URL.

Returns:

kwargs to be passed into sqlalchemy.create_engine().

ensure_schema_exists

ensure_schema_exists(session: "Session") -> None

Ensure that the requested PostgreSQL schema exists in the database.

Arguments:

  • session - Session used to inspect the database.

Raises:

ValueError if the requested schema does not exist.

SQLTrackerStore Objects

class SQLTrackerStore(TrackerStore)

Store which can save and retrieve trackers from an SQL database.

SQLEvent Objects

class SQLEvent(Base)

Represents an event in the SQL Tracker Store.

get_db_url

| @staticmethod
| get_db_url(dialect: Text = "sqlite", host: Optional[Text] = None, port: Optional[int] = None, db: Text = "rasa.db", username: Text = None, password: Text = None, login_db: Optional[Text] = None, query: Optional[Dict] = None) -> Union[Text, "URL"]

Build an SQLAlchemy URL object representing the parameters needed to connect to an SQL database.

Arguments:

  • dialect - SQL database type.
  • host - Database network host.
  • port - Database network port.
  • db - Database name.
  • username - User name to use when connecting to the database.
  • password - Password for database user.
  • login_db - Alternative database name to which initially connect, and create the database specified by db (PostgreSQL only).
  • query - Dictionary of options to be passed to the dialect and/or the DBAPI upon connect.

Returns:

URL ready to be used with an SQLAlchemy Engine object.

session_scope

| @contextlib.contextmanager
| session_scope() -> Generator["Session", None, None]

Provide a transactional scope around a series of operations.

keys

| keys() -> Iterable[Text]

Returns sender_ids of the SQLTrackerStore

save

| save(tracker: DialogueStateTracker) -> None

Update database with events from the current conversation.

FailSafeTrackerStore Objects

class FailSafeTrackerStore(TrackerStore)

Wraps a tracker store so that we can fallback to a different tracker store in case of errors.

__init__

| __init__(tracker_store: TrackerStore, on_tracker_store_error: Optional[Callable[[Exception], None]] = None, fallback_tracker_store: Optional[TrackerStore] = None) -> None

Create a FailSafeTrackerStore.

Arguments:

  • tracker_store - Primary tracker store.
  • on_tracker_store_error - Callback which is called when there is an error in the primary tracker store.