chariots Op Store

The OpStore is the Component of Chariots that handles persisting and reloading Operations. It also handles keeping track of the different versions of all the Ops that it registers.

As a Chariots user, you will need to setup the OpStore Server (using the OpStoreServer class) and than interact with the OpStore Client. Alternatively You can pass the OpStore client to your Chariots App and use this instead.

class chariots.op_store.OpStoreServer(saver, db_url='sqlite:///:memory:')[source]

The OpStore Server is the server that handles Saving and loading the different ops as well as keeping track of all the existing versions of each op.

To Create a server, you need to provide it with a saver (to know how to persist the Ops) and db_url (a sqlalchemy compatible url for the server to connect to the url)

>>> from chariots.op_store import savers
...
>>> saver = savers.FileSaver(saver_path)
>>> op_store_client = OpStoreServer(saver=saver, db_url=my_url)

The OpStore is created around a Flask app that you can access through the .flask attribute:

>>> op_store_client.flask
<Flask 'OpStoreServer'>

You can also access the .db and .migrate to control the db and potential migration (if newer versions of Chariots change the schema of the OpStore database for instance

Since this is a server, its public methods should not be accessed directly but instead through http (using the op store client)

The OpStore is mostly used by the Pipelines and the nodes at saving time to:

  • persist the ops that they have updated

  • register new versions

  • register links between different ops and different versions that are valid (for instance this versions of the PCA is valid for this new version of the RandomForest

and at loading time to:

  • check latest available version of an op

  • check if this version is valid with the rest of the pipeline

  • recover the bytes of the latest version if it is valid

the OpStore identifies op’s by there name (usually a snake case of the Class of your op) so changing this name (or changing the class name) might make it hard to recover the metadata and serialized bytes of the Ops.

Parameters

  • saver – the saver to use to persist the ops.

  • db_url – the URL of the database (where all the versions and pipeline informations are stored)

class chariots.op_store.OpStoreClient(url)[source]

Bases: chariots.op_store._op_store_client.BaseOpStoreClient

Client used to query the OpStoreServer.