HJ-319 Add DBCache model and table (#5613)

.fides/db_dataset.yml

@@ -2340,3 +2340,17 @@ dataset:
         data_categories: [system.operations]
       - name: updated_at
         data_categories: [system.operations]
+  - name: dbcache
+    fields:
+      - name: id
+        data_categories: [system.operations]
+      - name: namespace
+        data_categories: [system.operations]
+      - name: cache_key
+        data_categories: [system.operations]
+      - name: cache_value
+        data_categories: [system.operations]
+      - name: created_at
+        data_categories: [system.operations]
+      - name: updated_at
+        data_categories: [system.operations]

CHANGELOG.md

@@ -22,6 +22,7 @@ The types of changes are:
 - Added event based communication example to the Cookie House sample app [#5597](https://github.com/ethyca/fides/pull/5597)
 - Added new erasure tests for BigQuery Enterprise [#5554](https://github.com/ethyca/fides/pull/5554)
 - Added new `has_next` parameter for the `link` pagination strategy [#5596](https://github.com/ethyca/fides/pull/5596)
+- Added a `DBCache` model for database-backed caching [#5613](https://github.com/ethyca/fides/pull/5613)
 
 ### Changed
 - Adjusted Ant's Select component colors and icon [#5594](https://github.com/ethyca/fides/pull/5594)

src/fides/api/alembic/migrations/versions/e5ec30dfcd87_add_dbcache_table.py

@@ -0,0 +1,63 @@
+"""Add DBCache table
+
+Revision ID: e5ec30dfcd87
+Revises: c90d46f6d3f2
+Create Date: 2024-12-17 16:48:04.006190
+
+"""
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = "e5ec30dfcd87"
+down_revision = "c90d46f6d3f2"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table(
+        "dbcache",
+        sa.Column("id", sa.String(length=255), nullable=False),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=True,
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=True,
+        ),
+        sa.Column("namespace", sa.String(), nullable=False),
+        sa.Column("cache_key", sa.String(), nullable=False),
+        sa.Column("cache_value", postgresql.BYTEA(), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_dbcache_id"), "dbcache", ["id"], unique=False)
+    op.create_index(
+        op.f("ix_dbcache_namespace"), "dbcache", ["namespace"], unique=False
+    )
+    # Index over (namespace, cache_key), with unique set to True to ensure
+    # unique cache keys within a namespace
+    op.create_index(
+        op.f("ix_dbcache_namespace_cache_key"),
+        "dbcache",
+        ["namespace", "cache_key"],
+        unique=True,
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f("ix_dbcache_namespace"), table_name="dbcache")
+    op.drop_index(op.f("ix_dbcache_id"), table_name="dbcache")
+    op.drop_index(op.f("ix_dbcache_namespace_cache_key"), table_name="dbcache")
+    op.drop_table("dbcache")
+    # ### end Alembic commands ###

src/fides/api/db/base.py

@@ -12,6 +12,7 @@
 from fides.api.models.custom_connector_template import CustomConnectorTemplate
 from fides.api.models.custom_report import CustomReport
 from fides.api.models.datasetconfig import DatasetConfig
+from fides.api.models.db_cache import DBCache
 from fides.api.models.detection_discovery import MonitorConfig, StagedResource
 from fides.api.models.experience_notices import ExperienceNotices
 from fides.api.models.fides_cloud import FidesCloud

src/fides/api/models/db_cache.py

@@ -0,0 +1,89 @@
+from enum import Enum
+from typing import ByteString, Optional
+
+from sqlalchemy import Column, Index, String
+from sqlalchemy.dialects.postgresql import BYTEA
+from sqlalchemy.orm import Session
+
+from fides.api.db.base_class import Base
+
+
+class DBCacheNamespace(Enum):
+    """Namespaces for the DBCache"""
+
+    LIST_PRIVACY_EXPERIENCE = "list-privacy-experience"
+
+
+class DBCache(Base):
+    """
+    Cache table for storing arbitrary data, useful when in-memory caches aren't enough.
+    For example if cache contents need to be persisted across server restarts,
+    or if the cache needs to be shared across different Fides instances.
+
+    Warning: Cache contents are NOT encrypted, this shouldn't be used for storing
+    any sort of personal data or sensitive information.
+    """
+
+    namespace = Column(
+        String, nullable=False, index=True
+    )  # Add a namespace since the same cache key could technically be used for different contexts
+    cache_key = Column(String, nullable=False)
+    cache_value = Column(BYTEA, nullable=False)
+
+    __table_args__ = (
+        Index("ix_dbcache_namespace_cache_key", "namespace", "cache_key"),
+    )
+
+    @classmethod
+    def get_cache_entry(
+        cls,
+        db: Session,
+        namespace: DBCacheNamespace,
+        cache_key: str,
+    ) -> Optional["DBCache"]:
+        """
+        Retrieves the cache entry for the given cache_key
+        """
+        return (
+            db.query(cls)
+            .filter(cls.namespace == namespace.value, cls.cache_key == cache_key)
+            .first()
+        )
+
+    @classmethod
+    def get_cache_value(
+        cls,
+        db: Session,
+        namespace: DBCacheNamespace,
+        cache_key: str,
+    ) -> Optional[ByteString]:
+        """
+        Retrieves the cache value for the given cache_key
+        """
+        cache_entry = cls.get_cache_entry(db, namespace, cache_key)
+
+        return cache_entry.cache_value if cache_entry else None
+
+    @classmethod
+    def set_cache_value(
+        cls,
+        db: Session,
+        namespace: DBCacheNamespace,
+        cache_key: str,
+        cache_value: ByteString,
+    ) -> "DBCache":
+        """
+        Upserts the cache value for the given cache_key
+        """
+        db_cache_entry = cls.get_cache_entry(db, namespace, cache_key)
+        if db_cache_entry:
+            db_cache_entry.cache_value = cache_value
+        else:
+            db_cache_entry = cls(
+                namespace=namespace.value, cache_key=cache_key, cache_value=cache_value
+            )
+
+        db.add(db_cache_entry)
+        db.commit()
+        db.refresh(db_cache_entry)
+        return db_cache_entry

tests/ops/models/test_dbcache.py

@@ -0,0 +1,53 @@
+from fides.api.models.db_cache import DBCache, DBCacheNamespace
+
+
+class TestDBCacheModel:
+    def test_get_nonexisting_entry(self, db):
+        cache_value = DBCache.get_cache_value(
+            db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "nonexisting"
+        )
+        assert cache_value is None
+
+    def test_set_and_get_cache_value(self, db):
+        cache_value = DBCache.set_cache_value(
+            db,
+            DBCacheNamespace.LIST_PRIVACY_EXPERIENCE,
+            "some-key",
+            '{"some": "value", "another": "value"}'.encode(),
+        )
+        assert (
+            cache_value.cache_value.decode() == '{"some": "value", "another": "value"}'
+        )
+
+        cache_value = DBCache.get_cache_value(
+            db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key"
+        )
+        assert cache_value.decode() == '{"some": "value", "another": "value"}'
+
+    def test_update_cache_value(self, db):
+        # First we set a value
+        cache_value = DBCache.set_cache_value(
+            db,
+            DBCacheNamespace.LIST_PRIVACY_EXPERIENCE,
+            "some-key",
+            "value 1".encode(),
+        )
+        assert cache_value.cache_value.decode() == "value 1"
+        assert (
+            DBCache.get_cache_value(
+                db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key"
+            ).decode()
+            == "value 1"
+        )
+
+        # Update the cache value
+        cache_value = DBCache.set_cache_value(
+            db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key", "value 2".encode()
+        )
+        assert cache_value.cache_value.decode() == "value 2"
+
+        # Check the value was actually updated
+        updated_value = DBCache.get_cache_value(
+            db, DBCacheNamespace.LIST_PRIVACY_EXPERIENCE, "some-key"
+        )
+        assert updated_value.decode() == "value 2"