feat(storage): implement unified persistence layer with database models and repositories

backend/packages/storage/store/persistence/__init__.py

@@ -0,0 +1,23 @@
+from store.persistence.base_model import (
+    Base,
+    DataClassBase,
+    DateTimeMixin,
+    MappedBase,
+    TimeZone,
+    UniversalText,
+    id_key,
+)
+from .factory import create_persistence
+from .types import AppPersistence
+
+__all__ = [
+    "Base",
+    "DataClassBase",
+    "DateTimeMixin",
+    "MappedBase",
+    "TimeZone",
+    "UniversalText",
+    "id_key",
+    "create_persistence",
+    "AppPersistence"
+]

backend/packages/storage/store/persistence/base_model.py

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+from datetime import datetime
+from typing import Annotated
+
+from sqlalchemy import BigInteger, DateTime, Integer, Text, TypeDecorator
+from sqlalchemy.dialects.mysql import LONGTEXT
+from sqlalchemy.ext.asyncio import AsyncAttrs
+from sqlalchemy.orm import DeclarativeBase, Mapped, MappedAsDataclass, declared_attr, mapped_column
+
+from store.common import DataBaseType
+from store.config.app_config import get_app_config
+from store.utils import get_timezone
+
+timezone = get_timezone()
+app_config = get_app_config()
+
+# SQLite autoincrement only works with INTEGER PRIMARY KEY (not BIGINT)
+_id_type = Integer if app_config.storage.driver == DataBaseType.sqlite else BigInteger
+
+id_key = Annotated[
+    int,
+    mapped_column(
+        _id_type,
+        primary_key=True,
+        unique=True,
+        index=True,
+        autoincrement=True,
+        sort_order=-999,
+        comment="Primary key ID",
+    )
+]
+
+
+class UniversalText(TypeDecorator[str]):
+    """Cross-dialect long text type (LONGTEXT on MySQL, Text on PostgreSQL)."""
+
+    impl = LONGTEXT if DataBaseType.mysql == app_config.storage.driver else Text
+    cache_ok = True
+
+    def process_bind_param(self, value: str | None, dialect) -> str | None:  # noqa: ANN001
+        return value
+
+    def process_result_value(self, value: str | None, dialect) -> str | None:  # noqa: ANN001
+        return value
+
+
+class TimeZone(TypeDecorator[datetime]):
+    """Timezone-aware datetime type compatible with PostgreSQL and MySQL."""
+
+    impl = DateTime(timezone=True)
+    cache_ok = True
+
+    @property
+    def python_type(self) -> type[datetime]:
+        return datetime
+
+    def process_bind_param(self, value: datetime | None, dialect) -> datetime | None:  # noqa: ANN001
+        if value is not None and value.utcoffset() != timezone.now().utcoffset():
+            value = timezone.from_datetime(value)
+        return value
+
+    def process_result_value(self, value: datetime | None, dialect) -> datetime | None:  # noqa: ANN001
+        if value is not None and value.tzinfo is None:
+            value = value.replace(tzinfo=timezone.tz_info)
+        return value
+
+
+class DateTimeMixin(MappedAsDataclass):
+    """Mixin that adds created_time / updated_time columns."""
+
+    created_time: Mapped[datetime] = mapped_column(
+        TimeZone,
+        init=False,
+        default_factory=timezone.now,
+        sort_order=999,
+        comment="Created at",
+    )
+    updated_time: Mapped[datetime | None] = mapped_column(
+        TimeZone,
+        init=False,
+        onupdate=timezone.now,
+        sort_order=999,
+        comment="Updated at",
+    )
+
+
+class MappedBase(AsyncAttrs, DeclarativeBase):
+    """Async-capable declarative base for all ORM models."""
+
+    @declared_attr.directive
+    def __tablename__(self) -> str:
+        return self.__name__.lower()
+
+    @declared_attr.directive
+    def __table_args__(self) -> dict:
+        return {"comment": self.__doc__ or ""}
+
+
+class DataClassBase(MappedAsDataclass, MappedBase):
+    """Declarative base with native dataclass integration."""
+
+    __abstract__ = True
+
+
+class Base(DataClassBase, DateTimeMixin):
+    """Declarative dataclass base with created_time / updated_time columns."""
+
+    __abstract__ = True

backend/packages/storage/store/persistence/drivers/__init__.py

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+from .mysql import build_mysql_persistence
+from .postgres import build_postgres_persistence
+from .sqlite import build_sqlite_persistence
+
+__all__ = [
+    "build_postgres_persistence",
+    "build_mysql_persistence",
+    "build_sqlite_persistence",
+]

backend/packages/storage/store/persistence/drivers/mysql.py

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+from __future__ import annotations
+
+from sqlalchemy import URL
+from sqlalchemy.engine import make_url
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from store.persistence import MappedBase
+from store.persistence.shared import close_in_order
+from store.persistence.types import AppPersistence
+
+
+def _validate_mysql_driver(db_url: str) -> str:
+    url = make_url(db_url)
+    driver = url.get_driver_name()
+
+    if driver not in {"aiomysql", "asyncmy"}:
+        raise ValueError(
+            "MySQL persistence requires async SQLAlchemy driver "
+            f"(aiomysql/asyncmy), got: {driver!r}"
+        )
+    return driver
+
+
+async def build_mysql_persistence(db_url: URL) -> AppPersistence:
+    _validate_mysql_driver(db_url)
+
+    from langgraph.checkpoint.mysql.aio import AIOMySQLSaver
+
+    engine = create_async_engine(
+        db_url,
+        future=True,
+    )
+
+    session_factory = async_sessionmaker(
+        bind=engine,
+        class_=AsyncSession,
+        expire_on_commit=False,
+        autoflush=False,
+    )
+
+    saver_cm = AIOMySQLSaver.from_conn_string(db_url)
+    checkpointer = await saver_cm.__aenter__()
+
+    async def setup() -> None:
+        # 1. LangGraph checkpoint tables / migrations
+        await checkpointer.setup()
+
+        # 2. ORM business tables
+        async with engine.begin() as conn:
+            await conn.run_sync(MappedBase.metadata.create_all)
+
+    async def _close_saver() -> None:
+        await saver_cm.__aexit__(None, None, None)
+
+    async def aclose() -> None:
+        await close_in_order(
+            engine.dispose,
+            _close_saver,
+        )
+
+    return AppPersistence(
+        checkpointer=checkpointer,
+        engine=engine,
+        session_factory=session_factory,
+        setup=setup,
+        aclose=aclose,
+    )

backend/packages/storage/store/persistence/drivers/postgres.py

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+from __future__ import annotations
+
+from sqlalchemy import URL
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from store.persistence import MappedBase
+from store.persistence.shared import close_in_order
+from store.persistence.types import AppPersistence
+
+
+async def build_postgres_persistence(db_url: URL) -> AppPersistence:
+    from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
+
+    engine = create_async_engine(
+        db_url,
+        future=True,
+    )
+
+    session_factory = async_sessionmaker(
+        bind=engine,
+        class_=AsyncSession,
+        expire_on_commit=False,
+        autoflush=False,
+    )
+
+    saver_cm = AsyncPostgresSaver.from_conn_string(db_url)
+    checkpointer = await saver_cm.__aenter__()
+
+    async def setup() -> None:
+        # 1. LangGraph checkpoint tables / migrations
+        await checkpointer.setup()
+
+        # 2. ORM business tables
+        async with engine.begin() as conn:
+            await conn.run_sync(MappedBase.metadata.create_all)
+
+    async def _close_saver() -> None:
+        await saver_cm.__aexit__(None, None, None)
+
+    async def aclose() -> None:
+        await close_in_order(
+            engine.dispose,
+            _close_saver,
+        )
+
+    return AppPersistence(
+        checkpointer=checkpointer,
+        engine=engine,
+        session_factory=session_factory,
+        setup=setup,
+        aclose=aclose,
+    )

backend/packages/storage/store/persistence/drivers/sqlite.py

@@ -0,0 +1,53 @@
+
+from __future__ import annotations
+
+from sqlalchemy import URL
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from store.persistence import MappedBase
+from store.persistence.shared import close_in_order
+from store.persistence.types import AppPersistence
+
+
+async def build_sqlite_persistence(db_url: URL) -> AppPersistence:
+    from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
+
+    engine = create_async_engine(
+        db_url,
+        future=True,
+    )
+
+    session_factory = async_sessionmaker(
+        bind=engine,
+        class_=AsyncSession,
+        expire_on_commit=False,
+        autoflush=False,
+    )
+
+    saver_cm = AsyncSqliteSaver.from_conn_string(db_url.database)
+    checkpointer = await saver_cm.__aenter__()
+
+    async def setup() -> None:
+        # 1. LangGraph checkpoint tables
+        await checkpointer.setup()
+
+        # 2. ORM business tables
+        async with engine.begin() as conn:
+            await conn.run_sync(MappedBase.metadata.create_all)
+
+    async def _close_saver() -> None:
+        await saver_cm.__aexit__(None, None, None)
+
+    async def aclose() -> None:
+        await close_in_order(
+            engine.dispose,
+            _close_saver,
+        )
+
+    return AppPersistence(
+        checkpointer=checkpointer,
+        engine=engine,
+        session_factory=session_factory,
+        setup=setup,
+        aclose=aclose,
+    )

backend/packages/storage/store/persistence/factory.py

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+from sqlalchemy import URL
+
+from store.common import DataBaseType
+from store.config.app_config import get_app_config
+from store.config.storage_config import StorageConfig
+from store.persistence.types import AppPersistence
+
+
+def _create_database_url(storage_config: StorageConfig) -> URL:
+    """Build an async SQLAlchemy URL from StorageConfig (sqlite/mysql/postgres)."""
+
+    if storage_config.driver == DataBaseType.sqlite:
+        driver = "sqlite+aiosqlite"
+    elif storage_config.driver == DataBaseType.mysql:
+        driver = "mysql+aiomysql"
+    elif storage_config.driver == DataBaseType.postgresql:
+        driver = "postgresql+asyncpg"
+    else:
+        raise ValueError(f"Unsupported database driver: {storage_config.driver}")
+
+    if storage_config.driver == DataBaseType.sqlite:
+        import os
+
+        db_path = storage_config.sqlite_storage_path
+        os.makedirs(os.path.dirname(db_path), exist_ok=True)
+
+        url = URL.create(
+            drivername=driver,
+            database=db_path,
+        )
+    else:
+        url = URL.create(
+            drivername=driver,
+            username=storage_config.username,
+            password=storage_config.password,
+            host=storage_config.host,
+            port=storage_config.port,
+            database=storage_config.db_name or "deerflow",
+        )
+
+    return url
+
+
+async def create_persistence() -> AppPersistence:
+    from .drivers.mysql import build_mysql_persistence
+    from .drivers.postgres import build_postgres_persistence
+    from .drivers.sqlite import build_sqlite_persistence
+
+    app_config = get_app_config()
+
+    driver = app_config.storage.driver
+    db_url = _create_database_url(app_config.storage)
+
+    if driver == "postgresql":
+        return await build_postgres_persistence(db_url)
+
+    if driver == "mysql":
+        return await build_mysql_persistence(db_url)
+
+    if driver == "sqlite":
+        return await build_sqlite_persistence(db_url)
+
+    raise ValueError(f"Unsupported database driver: {driver}")

backend/packages/storage/store/persistence/shared/__init__.py

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+from .close import close_in_order
+
+__all__ = ["close_in_order"]

backend/packages/storage/store/persistence/shared/close.py

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+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable
+
+
+AsyncCloser = Callable[[], Awaitable[None]]
+
+
+async def close_in_order(*closers: AsyncCloser) -> None:
+    """
+    Run async closers in order and raise the first error, if any.
+
+    Notes
+    -----
+    - Used to keep driver-specific close logic readable.
+    - We intentionally do not stop at first failure, so later resources
+      still get a chance to close.
+    """
+    first_error: Exception | None = None
+
+    for closer in closers:
+        try:
+            await closer()
+        except Exception as exc:
+            if first_error is None:
+                first_error = exc
+
+    if first_error is not None:
+        raise first_error

backend/packages/storage/store/persistence/types.py

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+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any, Awaitable, Callable
+
+from langgraph.types import Checkpointer
+from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession, async_sessionmaker
+
+
+AsyncSetup = Callable[[], Awaitable[None]]
+AsyncClose = Callable[[], Awaitable[None]]
+
+
+@dataclass(slots=True)
+class AppPersistence:
+    """
+    Unified runtime persistence bundle.
+    """
+    checkpointer: Checkpointer
+    engine: AsyncEngine
+    session_factory: async_sessionmaker[AsyncSession]
+    setup: AsyncSetup
+    aclose: AsyncClose