Tracker Stores

Tracker Stores

All conversations are stored within a tracker store. Rasa Core provides implementations for different store types out of the box. If you want to use another store, you can also build a custom tracker store by extending the TrackerStore class.

Contents

InMemoryTrackerStore (default)

Description
InMemoryTrackerStore is the default tracker store. It is used if no other tracker store is configured. It stores the conversation history in memory.

Note
As this store keeps all history in memory the entire history is lost if you restart Rasa Core.

Configuration
To use the InMemoryTrackerStore no configuration is needed.

SQLTrackerStore

Description
SQLTrackerStore can be used to store the conversation history in an SQL database. Storing your trackers this way allows you to query the event database by sender_id, timestamp, action name, intent name and typename.

Configuration
To set up Rasa Core with SQL the following steps are required:

  1. Add required configuration to your endpoints.yml
   tracker_store:
       type: SQL
       dialect: "sqlite"  # the dialect used to interact with the db
       url: ""  # (optional) host of the sql db, e.g. "localhost"
       db: "rasa.db"  # path to your db
       username:  # username used for authentication
       password:  # password used for authentication
       query: # optional dictionary to be added as a query string to the connection URL
         driver: my-driver
  1. To start the Rasa Core server using your SQL backend, add the --endpoints flag, e.g.:
   rasa run -m models --endpoints endpoints.yml

Parameters

Officially Compatible Databases

Oracle Configuration
To use the SQLTrackerStore with Oracle, there are a few additional steps. First, create a database tracker in your Oracle database and create a user with access to it. Create a sequence in the database with the following command, where username is the user you created:

   CREATE SEQUENCE username.events_seq;

Next you have to extend the Rasa Open Source image to include the necessary drivers and clients. First download the Oracle Instant Client from here, rename it to oracle.rpm and store it in the directory from where you’ll be building the docker image. Copy the following into a file called Dockerfile:

   FROM rasa/rasa:|version|-full
   # Switch to root user to install packages
   USER root
   RUN apt-get update -qq \
   && apt-get install -y --no-install-recommends \
   alien \
   libaio1 \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
   # Copy in oracle instaclient
   COPY oracle.rpm oracle.rpm
   # Install the Python wrapper library for the Oracle drivers
   RUN pip install cx-Oracle
   # Install Oracle client libraries
   RUN alien -i oracle.rpm
   USER 1001

Then build the docker image:

   docker build . -t rasa-oracle:|version|-oracle-full

Now you can configure the tracker store in the endpoints.yml as described above, and start the container. The dialect parameter with this setup will be oracle+cx_oracle.

RedisTrackerStore

Description
RedisTrackerStore can be used to store the conversation history in Redis. Redis is a fast in-memory key-value store which can optionally also persist data.

Configuration
To set up Rasa Core with Redis the following steps are required:

  1. Start your Redis instance

  2. Add required configuration to your endpoints.yml

   tracker_store:
       type: redis
       url: <url of the redis instance, e.g. localhost>
       port: <port of your redis instance, usually 6379>
       db: <number of your database within redis, e.g. 0>
       password: <password used for authentication>
       use_ssl: <whether or not the communication is encrypted, default `false`>
  1. To start the Rasa Core server using your configured Redis instance, add the --endpoints flag, e.g.:
   rasa run -m models --endpoints endpoints.yml

Parameters

MongoTrackerStore

Description
MongoTrackerStore can be used to store the conversation history in Mongo. MongoDB is a free and open-source cross-platform document-oriented NoSQL database.

Configuration

  1. Start your MongoDB instance.

  2. Add required configuration to your endpoints.yml

   tracker_store:
       type: mongod
       url: <url to your mongo instance, e.g. mongodb://localhost:27017>
       db: <name of the db within your mongo instance, e.g. rasa>
       username: <username used for authentication>
       password: <password used for authentication>
       auth_source: <database name associated with the user’s credentials>

You can also add more advanced configurations (like enabling ssl) by appending a parameter to the url field, e.g. mongodb://localhost:27017/?ssl=true

  1. To start the Rasa Core server using your configured MongoDB instance, add the --endpoints flag, e.g.:
   rasa run -m models --endpoints endpoints.yml

Parameters

Custom Tracker Store

Description
If you require a tracker store which is not available out of the box, you can implement your own. This is done by extending the base class TrackerStore.

class rasa.core.tracker_store.TrackerStore(domain, event_broker=None, retrieve_events_from_previous_conversation_sessions=False):

Steps

  1. Extend the TrackerStore base class. Note that your constructor has to provide a parameter url.

  2. In your endpoints.yml put in the module path to your custom tracker store and the parameters you require:

   tracker_store:
     type: path.to.your.module.Class
     url: localhost
     a_parameter: a value
     another_parameter: another value

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