[Refactor] Outbox Architecture Overhaul: PostgreSQL Support, Mixin Models, and UUID v7

README.md

@@ -590,7 +590,22 @@ await broker.send_message(...)
 The package implements the [Transactional Outbox](https://microservices.io/patterns/data/transactional-outbox.html)
 pattern, which ensures that messages are produced to the broker according to the at-least-once semantics.
 
+To use the outbox pattern with SQLAlchemy, you first need to define your outbox model using the provided mixin:
+
 ```python
+from sqlalchemy.orm import DeclarativeBase
+from cqrs.outbox import OutboxModelMixin
+
+class Base(DeclarativeBase):
+    pass
+
+class OutboxModel(Base, OutboxModelMixin):
+    __tablename__ = "outbox"  # You can customize the table name
+```
+Then, you can use SqlAlchemyOutboxedEventRepository in your handlers:
+```python
+import cqrs
+
 def do_some_logic(meeting_room_id: int, session: sql_session.AsyncSession):
     """
     Make changes to the database

pyproject.toml

@@ -21,17 +21,17 @@ dependencies = [
   "dependency-injector>=4.0",
   "orjson==3.*",
   "pydantic==2.*",
-  "python-dotenv==1.*",
   "retry-async==0.1.*",
-  "sqlalchemy[asyncio]==2.0.*",
+  "python-dotenv==1.*",
+  "uuid6>=2025.0.1",
   "typing-extensions>=4.0"
 ]
 description = "Event-Driven Architecture Framework for Distributed Systems"
 maintainers = [{name = "Vadim Kozyrevskiy", email = "vadikko2@mail.ru"}]
 name = "python-cqrs"
 readme = "README.md"
 requires-python = ">=3.10"
-version = "4.8.1"
+version = "4.8.2"
 
 [project.optional-dependencies]
 aiobreaker = ["aiobreaker>=0.3.0"]
@@ -52,6 +52,7 @@ dev = [
   "pytest-asyncio~=0.21.1",
   "pytest-env==0.6.2",
   "cryptography==42.0.2",
+  "sqlalchemy[asyncio]==2.0.*",
   "asyncmy==0.2.9",
   "redis>=5.0.0",
   # Circuit breaker for tests

src/cqrs/events/event.py

@@ -4,6 +4,7 @@
 import os
 import sys
 import typing
+import uuid6
 import uuid
 
 import dotenv
@@ -289,7 +290,7 @@ class UserRegisteredEvent(DCNotificationEvent[dict]):
     event_name: str
     payload: PayloadT
 
-    event_id: uuid.UUID = dataclasses.field(default_factory=uuid.uuid4)
+    event_id: uuid.UUID = dataclasses.field(default_factory=uuid6.uuid7)
     event_timestamp: datetime.datetime = dataclasses.field(
         default_factory=datetime.datetime.now,
     )
@@ -350,7 +351,7 @@ class UserRegisteredEvent(PydanticNotificationEvent[dict]):
 
     payload: PayloadT
 
-    event_id: uuid.UUID = pydantic.Field(default_factory=uuid.uuid4)
+    event_id: uuid.UUID = pydantic.Field(default_factory=uuid6.uuid7)
     event_timestamp: datetime.datetime = pydantic.Field(
         default_factory=datetime.datetime.now,
     )

src/cqrs/outbox/__init__.py

@@ -0,0 +1,20 @@
+from cqrs.outbox.repository import OutboxedEventRepository, EventStatus
+from cqrs.outbox.map import OutboxedEventMap
+
+__all__ = [
+    "OutboxedEventRepository",
+    "EventStatus",
+    "OutboxedEventMap",
+]
+
+try:
+    from cqrs.outbox.sqlalchemy import (
+        SqlAlchemyOutboxedEventRepository,
+        OutboxModelMixin
+    )
+    __all__.extend([
+        "SqlAlchemyOutboxedEventRepository",
+        "OutboxModelMixin"
+    ])
+except ImportError:
+    pass

src/cqrs/outbox/sqlalchemy.py

@@ -1,93 +1,125 @@
+import datetime
 import logging
 import typing
-
-import dotenv
+import uuid
 import orjson
-import sqlalchemy
-from sqlalchemy import func
-from sqlalchemy.dialects import mysql
-from sqlalchemy.ext.asyncio import session as sql_session
-from sqlalchemy.orm import DeclarativeMeta, registry
+import uuid6
 
 import cqrs
 from cqrs import compressors
 from cqrs.outbox import map, repository
 
-Base = registry().generate_base()
-
-logger = logging.getLogger(__name__)
+try:
+    import sqlalchemy
+    from sqlalchemy import func
+    from sqlalchemy.orm import Mapped, mapped_column, declared_attr
+    from sqlalchemy.ext.asyncio import session as sql_session
+    from sqlalchemy.dialects import postgresql
+except ImportError:
+    raise ImportError(
+        "You are trying to use SQLAlchemy outbox implementation, "
+        "but 'sqlalchemy' is not installed. "
+        "Please install it using: pip install python-cqrs[sqlalchemy]"
+    )
 
-dotenv.load_dotenv()
 
+logger = logging.getLogger(__name__)
 DEFAULT_OUTBOX_TABLE_NAME = "outbox"
-
 MAX_FLUSH_COUNTER_VALUE = 5
 
 
-class OutboxModel(Base):
-    __tablename__ = DEFAULT_OUTBOX_TABLE_NAME
-
-    __table_args__ = (
-        sqlalchemy.UniqueConstraint(
-            "event_id_bin",
-            "event_name",
-            name="event_id_unique_index",
-        ),
-    )
-    id = sqlalchemy.Column(
-        sqlalchemy.BigInteger(),
+class BinaryUUID(sqlalchemy.TypeDecorator):
+    """Stores the UUID as a native UUID in Postgres and as BINARY(16) in other databases (MySQL)."""
+    impl = sqlalchemy.BINARY(16)
+    cache_ok = True
+
+    def load_dialect_impl(self, dialect):
+        if dialect.name == "postgresql":
+            return dialect.type_descriptor(postgresql.UUID())
+        else:
+            return dialect.type_descriptor(sqlalchemy.BINARY(16))
+
+    def process_bind_param(self, value, dialect):
+        if value is None:
+            return value
+        if dialect.name == "postgresql":
+            return value  # asyncpg work with uuid.UUID
+        if isinstance(value, uuid.UUID):
+            return value.bytes # For MySQL return 16 bytes
+        return value
+
+    def process_result_value(self, value, dialect):
+        if value is None:
+            return value
+        if dialect.name == "postgresql":
+            return value # asyncpg return uuid.UUID
+        if isinstance(value, bytes):
+            return uuid.UUID(bytes=value) # From MySQL got bytes, make UUID
+        return value
+
+
+class OutboxModelMixin:
+    @declared_attr.directive
+    def __tablename__(self) -> str:
+        return DEFAULT_OUTBOX_TABLE_NAME
+
+    id: Mapped[int] = mapped_column(
+        sqlalchemy.BigInteger,
         sqlalchemy.Identity(),
         primary_key=True,
         nullable=False,
-        autoincrement=True,
         comment="Identity",
     )
-    event_id = sqlalchemy.Column(
-        sqlalchemy.Uuid,
+    event_id: Mapped[uuid.UUID] = mapped_column(
+        BinaryUUID,
         nullable=False,
         comment="Event idempotency id",
     )
-    event_id_bin = sqlalchemy.Column(
-        sqlalchemy.BINARY(16),
-        nullable=False,
-        comment="Event idempotency id in 16 bit presentation",
-    )
-    event_status = sqlalchemy.Column(
+    event_status: Mapped[repository.EventStatus] = mapped_column(
         sqlalchemy.Enum(repository.EventStatus),
         nullable=False,
         default=repository.EventStatus.NEW,
         comment="Event producing status",
     )
-    flush_counter = sqlalchemy.Column(
-        sqlalchemy.SmallInteger(),
+    flush_counter: Mapped[int] = mapped_column(
+        sqlalchemy.SmallInteger,
         nullable=False,
         default=0,
         comment="Event producing flush counter",
     )
-    event_name = sqlalchemy.Column(
+    event_name: Mapped[typing.Text] = mapped_column(
         sqlalchemy.String(255),
         nullable=False,
         comment="Event name",
     )
-    topic = sqlalchemy.Column(
+    topic: Mapped[typing.Text] = mapped_column(
         sqlalchemy.String(255),
         nullable=False,
-        comment="Event topic",
         default="",
+        comment="Event topic",
     )
-    created_at = sqlalchemy.Column(
+    created_at: Mapped[datetime.datetime] = mapped_column(
         sqlalchemy.DateTime,
         nullable=False,
         server_default=func.now(),
         comment="Event creation timestamp",
     )
-    payload = sqlalchemy.Column(
-        mysql.BLOB,
+    payload: Mapped[bytes] = mapped_column(
+        sqlalchemy.LargeBinary,
         nullable=False,
-        default={},
         comment="Event payload",
     )
 
+    @declared_attr
+    def __table_args__(self):
+        return (
+            sqlalchemy.UniqueConstraint(
+                "event_id",
+                "event_name",
+                name="event_id_unique_index",
+            ),
+        )
+
     def row_to_dict(self) -> typing.Dict[typing.Text, typing.Any]:
         return {
             column.name: getattr(self, column.name) for column in self.__table__.columns
@@ -153,10 +185,12 @@ class SqlAlchemyOutboxedEventRepository(repository.OutboxedEventRepository):
     def __init__(
         self,
         session: sql_session.AsyncSession,
+        outbox_model: type[OutboxModelMixin],
         compressor: compressors.Compressor | None = None,
     ):
         self.session = session
         self._compressor = compressor
+        self._outbox_model = outbox_model
 
     def add(
         self,
@@ -176,17 +210,16 @@ def add(
             bytes_payload = self._compressor.compress(bytes_payload)
 
         self.session.add(
-            OutboxModel(
+            self._outbox_model(
                 event_id=event.event_id,
-                event_id_bin=func.UUID_TO_BIN(event.event_id),
                 event_name=event.event_name,
                 created_at=event.event_timestamp,
                 payload=bytes_payload,
                 topic=event.topic,
             ),
         )
 
-    def _process_events(self, model: OutboxModel) -> repository.OutboxedEvent | None:
+    def _process_events(self, model: OutboxModelMixin) -> repository.OutboxedEvent | None:
         event_dict = model.row_to_dict()
 
         event_model = map.OutboxedEventMap.get(event_dict["event_name"])
@@ -211,8 +244,8 @@ async def get_many(
         batch_size: int = 100,
         topic: typing.Text | None = None,
     ) -> typing.List[repository.OutboxedEvent]:
-        events: typing.Sequence[OutboxModel] = (
-            (await self.session.execute(OutboxModel.get_batch_query(batch_size, topic)))
+        events: typing.Sequence[OutboxModelMixin] = (
+            (await self.session.execute(self._outbox_model.get_batch_query(batch_size, topic)))
             .scalars()
             .all()
         )
@@ -233,7 +266,7 @@ async def update_status(
         new_status: repository.EventStatus,
     ) -> None:
         await self.session.execute(
-            statement=OutboxModel.update_status_query(outboxed_event_id, new_status),
+            statement=self._outbox_model.update_status_query(outboxed_event_id, new_status),
         )
 
     async def commit(self):
@@ -243,6 +276,7 @@ async def rollback(self):
         await self.session.rollback()
 
 
+@warnings.deprecated()
 def rebind_outbox_model(
     model: typing.Any,
     new_base: DeclarativeMeta,

src/cqrs/saga/storage/sqlalchemy.py

@@ -3,19 +3,25 @@
 import os
 import typing
 import uuid
-
-import dotenv
-import sqlalchemy
-from sqlalchemy import func
-from sqlalchemy.exc import SQLAlchemyError
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
-from sqlalchemy.orm import registry
-
 from cqrs.dispatcher.exceptions import SagaConcurrencyError
 from cqrs.saga.storage.enums import SagaStatus, SagaStepStatus
 from cqrs.saga.storage.models import SagaLogEntry
 from cqrs.saga.storage.protocol import ISagaStorage
 
+import dotenv
+try:
+    import sqlalchemy
+    from sqlalchemy import func
+    from sqlalchemy.exc import SQLAlchemyError
+    from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+    from sqlalchemy.orm import registry
+except ImportError:
+    raise ImportError(
+        "You are trying to use SQLAlchemy saga storage implementation, "
+        "but 'sqlalchemy' is not installed. "
+        "Please install it using: pip install python-cqrs[sqlalchemy]"
+    )
+
 Base = registry().generate_base()
 logger = logging.getLogger(__name__)
 

tests/conftest.py

@@ -1,26 +1,13 @@
-import asyncio
-from unittest import mock
-
 import pytest
-
+from unittest import mock
 from cqrs.adapters import kafka
 
+
 TEST_TOPIC = "TestCqrsTopic"
 
 pytest_plugins = ["tests.integration.fixtures"]
 
 
-@pytest.fixture(scope="session")
-def event_loop():
-    """Create event loop for session-scoped fixtures."""
-    loop = asyncio.new_event_loop()
-    try:
-        yield loop
-    finally:
-        if not loop.is_closed():
-            loop.close()
-
-
 @pytest.fixture(scope="function")
 async def kafka_producer() -> kafka.KafkaProducer:
     producer = mock.create_autospec(kafka.KafkaProducer)