Warning: This document is for an old version of Rasa. The latest version is 1.10.8.

Tracker

Trackers maintain the state of a dialogue between the assistant and the user in the form of conversation sessions. To learn more about how to configure the session behaviour, check out the docs on Session configuration.

class rasa.core.trackers.DialogueStateTracker(sender_id, slots, max_event_history=None, sender_source=None, is_rule_tracker=False)

Maintains the state of a conversation.

The field max_event_history will only give you these last events, it can be set in the tracker_store

active_form_name()

Get the name of the currently active form.

Returns: None if no active form or the name of the currenly active form.

Return type

Optional[str]

applied_events()

Returns all actions that should be applied - w/o reverted events.

Return type

List[Event]

as_dialogue()

Return a Dialogue object containing all of the turns.

This can be serialised and later used to recover the state of this tracker exactly.

Return type

Dialogue

change_form_to(form_name)

Activate or deactivate a form

Return type

None

clear_followup_action()

Clears follow up action when it was executed.

Return type

None

copy()

Creates a duplicate of this tracker

Return type

DialogueStateTracker

current_slot_values()

Return the currently set values of the slots

Return type

Dict[str, Any]

current_state(event_verbosity=<EventVerbosity.NONE: 1>)

Return the current tracker state as an object.

Return type

Dict[str, Any]

events_after_latest_restart()

Return a list of events after the most recent restart.

Return type

List[Event]

export_stories(e2e=False, include_source=False)

Dump the tracker as a story in the Rasa Core story format.

Returns the dumped tracker as a string.

Return type

str

export_stories_to_file(export_path='debug.md')

Dump the tracker as a story to a file.

Return type

None

classmethod from_dict(sender_id, events_as_dict, slots=None, max_event_history=None)

Create a tracker from dump.

The dump should be an array of dumped events. When restoring the tracker, these events will be replayed to recreate the state.

Return type

DialogueStateTracker

generate_all_prior_trackers()

Returns a generator of the previous trackers of this tracker.

The resulting array is representing the trackers before each action.

Return type

Generator[DialogueStateTracker, None, None]

get_last_event_for(event_type, action_names_to_exclude=None, skip=0, event_verbosity=<EventVerbosity.APPLIED: 2>)

Gets the last event of a given type which was actually applied.

Parameters
  • event_type – The type of event you want to find.

  • action_names_to_exclude – Events of type ActionExecuted which should be excluded from the results. Can be used to skip action_listen events.

  • skip – Skips n possible results before return an event.

  • event_verbosity – Which EventVerbosity should be used to search for events.

Returns

event which matched the query or None if no event matched.

Return type

Optional[Event]

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.

Parameters
  • entity_type – the entity type of interest

  • entity_role – optional entity role of interest

  • entity_group – optional entity group of interest

Returns

Entity values.

Return type

Iterator[str]

get_latest_input_channel()

Get the name of the input_channel of the latest UserUttered event

Return type

Optional[str]

get_slot(key)

Retrieves the value of a slot.

Return type

Optional[Any]

idx_after_latest_restart()

Return the idx of the most recent restart in the list of events.

If the conversation has not been restarted, 0 is returned.

Return type

int

init_copy()

Creates a new state tracker with the same initial values.

Return type

DialogueStateTracker

is_paused()

State whether the tracker is currently paused.

Return type

bool

last_executed_action_has(name, skip=0)

Returns whether last ActionExecuted event had a specific name.

Parameters
  • name – Name of the event which should be matched.

  • skip – Skips n possible results in between.

Returns

True if last executed action had name name, otherwise False.

Return type

bool

past_states(domain)

Generate the past states of this tracker based on the history.

Return type

deque

recreate_from_dialogue(dialogue)

Use a serialised Dialogue to update the trackers state.

This uses the state as is persisted in a TrackerStore. If the tracker is blank before calling this method, the final state will be identical to the tracker from which the dialogue was created.

Return type

None

reject_action(action_name)

Notify active form that it was rejected

Return type

None

replay_events()

Update the tracker based on a list of events.

Return type

None

set_form_validation(validate)

Toggle form validation

Return type

None

set_latest_action_name(action_name)

Set latest action name and reset form validation and rejection parameters

Return type

None

travel_back_in_time(target_time)

Creates a new tracker with a state at a specific timestamp.

A new tracker will be created and all events previous to the passed time stamp will be replayed. Events that occur exactly at the target time will be included.

Return type

DialogueStateTracker

trigger_followup_action(action)

Triggers another action following the execution of the current.

Return type

None

update(event, domain=None)

Modify the state of the tracker according to an Event.

Return type

None