Cassandra online store

* Refactor file-editing to a shared utils module * Use f-strings in the CassandraOnlineStoreCreator * Specify version 2 in serializing to make the entity key * Remove unnecessary empty comment lines * Rename proj to columns in _read_rows_by_entity_key * Introduce Cassandra-specific pytest targets * Adapt roadmaps and docs to cover/index Cassandra online store * Add license notes to code files Signed-off-by: Stefano Lottini <stefano.lottini@datastax.com>
feast-dev · Aug 9, 2022 · 02ac46e · 02ac46e
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diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -312,6 +312,7 @@ The services with containerized replacements currently implemented are:
 - Trino
 - HBase
 - Postgres
+- Cassandra
 
 You can run `make test-python-integration-container` to run tests against the containerized versions of dependencies.
 

diff --git a/Makefile b/Makefile
@@ -156,6 +156,35 @@ test-python-universal-postgres:
 				not test_universal_types" \
 			sdk/python/tests
 
+test-python-universal-cassandra:
+	PYTHONPATH='.' \
+	  FULL_REPO_CONFIGS_MODULE=sdk.python.feast.infra.online_stores.contrib.cassandra_repo_configuration \
+	  FEAST_USAGE=False \
+	  IS_TEST=True \
+	  python -m pytest -x --integration \
+	    sdk/python/tests
+
+test-python-universal-cassandra-no-cloud-providers:
+	PYTHONPATH='.' \
+  FULL_REPO_CONFIGS_MODULE=sdk.python.feast.infra.online_stores.contrib.cassandra_repo_configuration \
+  FEAST_USAGE=False \
+  IS_TEST=True \
+  python -m pytest -x --integration \
+    -k "not test_lambda_materialization_consistency   and \
+      not test_apply_entity_integration               and \
+      not test_apply_feature_view_integration         and \
+      not test_apply_entity_integration               and \
+      not test_apply_feature_view_integration         and \
+      not test_apply_data_source_integration          and \
+      not test_nullable_online_store " \
+    sdk/python/tests
+
+test-python-universal-cassandra-minimal:
+	FEAST_USAGE=False \
+	IS_TEST=True \
+	FEAST_LOCAL_ONLINE_CONTAINER=True \
+	python -m pytest -n0 --integration -k cassandra sdk/python/tests
+
 test-python-universal:
 	FEAST_USAGE=False IS_TEST=True python -m pytest -n 8 --integration sdk/python/tests
 

diff --git a/README.md b/README.md
@@ -177,7 +177,7 @@ The list below contains the functionality that contributors are planning to deve
   * [x] [Azure Cache for Redis (community plugin)](https://github.com/Azure/feast-azure)
   * [x] [Postgres (contrib plugin)](https://docs.feast.dev/reference/online-stores/postgres)
   * [x] [Custom online store support](https://docs.feast.dev/how-to-guides/adding-support-for-a-new-online-store)
-  * [x] [Cassandra / AstraDB](https://github.com/datastaxdevs/feast-cassandra-online-store)
+  * [x] [Cassandra / AstraDB](https://docs.feast.dev/reference/online-stores/cassandra)
   * [ ] Bigtable (in progress)
 * **Feature Engineering**
   * [x] On-demand Transformations (Alpha release. See [RFC](https://docs.google.com/document/d/1lgfIw0Drc65LpaxbUu49RCeJgMew547meSJttnUqz7c/edit#))

diff --git a/docs/reference/online-stores/README.md b/docs/reference/online-stores/README.md
@@ -25,3 +25,7 @@ Please see [Online Store](../../getting-started/architecture-and-components/onli
 {% content-ref url="postgres.md" %}
 [postgres.md](postgres.md)
 {% endcontent-ref %}
+
+{% content-ref url="cassandra.md" %}
+[cassandra.md](cassandra.md)
+{% endcontent-ref %}
diff --git a/docs/reference/online-stores/cassandra.md b/docs/reference/online-stores/cassandra.md
@@ -0,0 +1,61 @@
+# Cassandra / Astra DB online store
+
+## Description
+
+The [Cassandra / Astra DB] online store provides support for materializing feature values into an Apache Cassandra / Astra DB database for online features.
+
+* The whole project is contained within a Cassandra keyspace
+* Each feature view is mapped one-to-one to a specific Cassandra table
+* This implementation inherits all strengths of Cassandra such as high availability, fault-tolerance, and data distribution
+
+An easy way to get started is the command `feast init REPO_NAME -t cassandra`.
+
+### Example (Cassandra)
+
+{% code title="feature_store.yaml" %}
+```yaml
+project: my_feature_repo
+registry: data/registry.db
+provider: local
+online_store:
+    type: cassandra
+    hosts:
+        - 192.168.1.1
+        - 192.168.1.2
+        - 192.168.1.3
+    keyspace: KeyspaceName
+    port: 9042                                                              # optional
+    username: user                                                          # optional
+    password: secret                                                        # optional
+    protocol_version: 5                                                     # optional
+    load_balancing:                                                         # optional
+        local_dc: 'datacenter1'                                             # optional
+        load_balancing_policy: 'TokenAwarePolicy(DCAwareRoundRobinPolicy)'  # optional
+```
+{% endcode %}
+
+### Example (Astra DB)
+
+{% code title="feature_store.yaml" %}
+```yaml
+project: my_feature_repo
+registry: data/registry.db
+provider: local
+online_store:
+    type: cassandra
+    secure_bundle_path: /path/to/secure/bundle.zip
+    keyspace: KeyspaceName
+    username: Client_ID
+    password: Client_Secret
+    protocol_version: 4                                                     # optional
+    load_balancing:                                                         # optional
+        local_dc: 'eu-central-1'                                            # optional
+        load_balancing_policy: 'TokenAwarePolicy(DCAwareRoundRobinPolicy)'  # optional
+
+```
+{% endcode %}
+
+For a full explanation of configuration options please look at file
+`sdk/python/feast/infra/online_stores/contrib/cassandra_online_store/README.md`.
+
+Storage specifications can be found at `docs/specs/online_store_format.md`.
diff --git a/docs/roadmap.md b/docs/roadmap.md
@@ -35,7 +35,7 @@ The list below contains the functionality that contributors are planning to deve
   * [x] [Azure Cache for Redis (community plugin)](https://github.com/Azure/feast-azure)
   * [x] [Postgres (contrib plugin)](https://docs.feast.dev/reference/online-stores/postgres)
   * [x] [Custom online store support](https://docs.feast.dev/how-to-guides/adding-support-for-a-new-online-store)
-  * [x] [Cassandra / AstraDB](https://github.com/datastaxdevs/feast-cassandra-online-store)
+  * [x] [Cassandra / AstraDB](https://docs.feast.dev/reference/online-stores/cassandra)
   * [ ] Bigtable (in progress)
 * **Feature Engineering**
   * [x] On-demand Transformations (Alpha release. See [RFC](https://docs.google.com/document/d/1lgfIw0Drc65LpaxbUu49RCeJgMew547meSJttnUqz7c/edit#))

diff --git a/docs/specs/online_store_format.md b/docs/specs/online_store_format.md
@@ -92,6 +92,86 @@ Other types of entity keys are not supported in this version of the specificatio
 
 ![Datastore Online Example](datastore_online_example.png)
 
+## Cassandra/Astra DB Online Store Format
+
+### Overview
+
+Apache Cassandra™ is a table-oriented NoSQL distributed database. Astra DB is a managed database-as-a-service
+built on Cassandra, and will be assimilated to the former in what follows.
+
+In Cassandra, tables are grouped in _keyspaces_ (groups of related tables). Each table is comprised of
+_rows_, each containing data for a given set of _columns_. Moreover, rows are grouped in _partitions_ according
+to a _partition key_ (a portion of the uniqueness-defining _primary key_ set of columns), so that all rows
+with the same values for the partition key are guaranteed to be stored on the same Cassandra nodes, next to each other,
+which guarantees fast retrieval times.
+
+This architecture makes Cassandra a good fit for an online feature store in Feast.
+
+### Cassandra Online Store Format
+
+Each project (denoted by its name, called "feature store name" elsewhere) may contain an
+arbitrary number of `FeatureView`s: these correspond each to a specific table, and
+all tables for a project are to be contained in a single keyspace. The keyspace should
+have been created by the Feast user preliminarly and is to be specified in the feature store
+configuration `yaml`.
+
+The table for a project `project` and feature view `FeatureView` will have name
+`project_FeatureView` (e.g. `feature_repo_driver_hourly_stats`).
+
+All tables have the same structure. Cassandra is schemaful and the columns are strongly typed.
+In the following table schema (which also serves as Chebotko diagram) the Python
+and Cassandra data types are both specified:
+
+|Table:         |`<project>`_`<FeatureView>`  |  | _(Python type)_      |
+|---------------|-----------------------------|--|----------------------|
+|`entity_key`   |`TEXT`                       |K | `str`                |
+|`feature_name` |`TEXT`                       |C↑| `str`                |
+|`value`        |`BLOB`                       |  | `bytes`              |
+|`event_ts`     |`TIMESTAMP`                  |  | `datetime.datetime`  |
+|`created_ts`   |`TIMESTAMP`                  |  | `datetime.datetime`  |
+
+Each row in the table represents a single value for a feature in a feature view,
+thus associated to a specific entity. The choice of partitioning ensures that,
+within a given feature view (i.e. a single table), for a given entity any number
+of features can be retrieved with a single, best-practice-respecting query
+(which is what happens in the `online_read` method implementation).
+
+
+The `entity_key` column is computed as `serialize_entity_key(entityKey).hex()`,
+where `entityKey` is of type `feast.protos.feast.types.EntityKey_pb2.EntityKey`.
+
+The value of `feature_name` is the plain-text name of the feature as defined
+in the corresponding `FeatureView`.
+
+For `value`, the bytes from `[protoValue].SerializeToString()`
+are used, where `protoValue` is of type `feast.protos.feast.types.Value_pb2.Value`.
+
+Column `event_ts` stores the timestamp the feature value refers to, as passed
+to the store method. Conversely, column `created_ts`, meant to store the write
+time for the entry, is now being deprecated and will be never written by this
+online-store implementation. Thanks to the internal storage mechanism of Cassandra,
+this does not incur a noticeable performance penalty (hence, for the time being,
+the column can be maintained in the schema).
+
+### Example entry
+
+For a project `feature_repo` and feature view named `driver_hourly_stats`,
+a typical row in table `feature_repo_driver_hourly_stats` might look like:
+
+|Column         |content                                              | notes                                                             |
+|---------------|-----------------------------------------------------|-------------------------------------------------------------------|
+|`entity_key`   |`020000006472697665725f69640400000004000000ea030000` | from `"driver_id = 1002"`                                         |
+|`feature_name` |`conv_rate`                                          |                                                                   |
+|`value`        |`0x35f5696d3f`                                       | from `float_val: 0.9273980259895325`, i.e. `(b'5\xf5im?').hex()`  |
+|`event_ts`     |`2022-07-07 09:00:00.000000+0000`                    | from `datetime.datetime(2022, 7, 7, 9, 0)`                        |
+|`created_ts`   |`null`                                               | not explicitly written to avoid unnecessary tombstones            |
+
+### Known Issues
+
+If a `FeatureView` ever gets _re-defined_ in a schema-breaking way, the implementation is not able to rearrange the
+schema of the underlying table accordingly (neither dropping all data nor, even less so, keeping it somehow).
+This should never occur, lest one encounters all sorts of data-retrieval issues anywhere in Feast usage.
+
 # Appendix
 
 ##### Appendix A. Value proto format.

diff --git a/sdk/python/docs/index.rst b/sdk/python/docs/index.rst
@@ -287,6 +287,13 @@ HBase Online Store
     :members:
     :noindex:
 
+Cassandra Online Store
+-----------------------
+
+.. automodule:: feast.infra.online_stores.contrib.cassandra_online_store.cassandra_online_store
+    :members:
+    :noindex:
+
 
 Batch Materialization Engine
 ============================

diff --git a/sdk/python/docs/source/feast.infra.offline_stores.contrib.rst b/sdk/python/docs/source/feast.infra.offline_stores.contrib.rst
@@ -14,18 +14,26 @@ Subpackages
 Submodules
 ----------
 
-feast.infra.offline\_stores.contrib.contrib\_repo\_configuration module
------------------------------------------------------------------------
+feast.infra.offline\_stores.contrib.postgres\_repo\_configuration module
+------------------------------------------------------------------------
 
-.. automodule:: feast.infra.offline_stores.contrib.contrib_repo_configuration
+.. automodule:: feast.infra.offline_stores.contrib.postgres_repo_configuration
    :members:
    :undoc-members:
    :show-inheritance:
 
-feast.infra.offline\_stores.contrib.postgres\_repo\_configuration module
-------------------------------------------------------------------------
+feast.infra.offline\_stores.contrib.spark\_repo\_configuration module
+---------------------------------------------------------------------
 
-.. automodule:: feast.infra.offline_stores.contrib.postgres_repo_configuration
+.. automodule:: feast.infra.offline_stores.contrib.spark_repo_configuration
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+feast.infra.offline\_stores.contrib.trino\_repo\_configuration module
+---------------------------------------------------------------------
+
+.. automodule:: feast.infra.offline_stores.contrib.trino_repo_configuration
    :members:
    :undoc-members:
    :show-inheritance:

diff --git a/...python/docs/source/feast.infra.online_stores.contrib.cassandra_online_store.rst b/...python/docs/source/feast.infra.online_stores.contrib.cassandra_online_store.rst
@@ -0,0 +1,21 @@
+feast.infra.online\_stores.contrib.cassandra\_online\_store package
+===================================================================
+
+Submodules
+----------
+
+feast.infra.online\_stores.contrib.cassandra\_online\_store.cassandra\_online\_store module
+-------------------------------------------------------------------------------------------
+
+.. automodule:: feast.infra.online_stores.contrib.cassandra_online_store.cassandra_online_store
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+Module contents
+---------------
+
+.. automodule:: feast.infra.online_stores.contrib.cassandra_online_store
+   :members:
+   :undoc-members:
+   :show-inheritance:
diff --git a/sdk/python/docs/source/feast.infra.online_stores.contrib.rst b/sdk/python/docs/source/feast.infra.online_stores.contrib.rst
@@ -7,6 +7,7 @@ Subpackages
 .. toctree::
    :maxdepth: 4
 
+   feast.infra.online_stores.contrib.cassandra_online_store
    feast.infra.online_stores.contrib.hbase_online_store
 
 Submodules

diff --git a/sdk/python/docs/source/feast.rst b/sdk/python/docs/source/feast.rst
@@ -169,6 +169,14 @@ feast.field module
    :undoc-members:
    :show-inheritance:
 
+feast.file\_utils module
+------------------------
+
+.. automodule:: feast.file_utils
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 feast.flags\_helper module
 --------------------------
 

diff --git a/sdk/python/docs/source/index.rst b/sdk/python/docs/source/index.rst
@@ -287,6 +287,13 @@ HBase Online Store
     :members:
     :noindex:
 
+Cassandra Online Store
+-----------------------
+
+.. automodule:: feast.infra.online_stores.contrib.cassandra_online_store.cassandra_online_store
+    :members:
+    :noindex:
+
 
 Batch Materialization Engine
 ============================

diff --git a/sdk/python/feast/cli.py b/sdk/python/feast/cli.py
@@ -590,7 +590,7 @@ def materialize_incremental_command(ctx: click.Context, end_ts: str, views: List
     "--template",
     "-t",
     type=click.Choice(
-        ["local", "gcp", "aws", "snowflake", "spark", "postgres", "hbase"],
+        ["local", "gcp", "aws", "snowflake", "spark", "postgres", "hbase", "cassandra"],
         case_sensitive=False,
     ),
     help="Specify a template for the created project",