async sqlmodel

This commit is contained in:
John Lancaster
2026-06-26 00:53:18 -05:00
parent 0177496fab
commit eeeb6ecdbe
4 changed files with 152 additions and 3 deletions
@@ -13,6 +13,7 @@ Purpose: concept registry for modernization guidance used by this skill.
| Transaction boundaries | [transactions.md](transactions.md) | adopted | mandatory | platform/backend | 2026-06-17 |
| Implicit ORM I/O under asyncio | [implicit_io.md](implicit_io.md) | adopted | advisory | platform/backend | 2026-06-17 |
| Observability and resilience | [observability.md](observability.md) | adopted | mandatory | platform/backend | 2026-06-17 |
| SQLModel adoption and boundaries | [sqlmodel.md](sqlmodel.md) | adopted | advisory | platform/backend | 2026-06-26 |
---
@@ -57,7 +57,7 @@ async def get_db_session(
session_factory: async_sessionmaker[AsyncSession] = Depends(get_session_factory),
) -> AsyncIterator[AsyncSession]:
async with session_factory() as session:
yield session
yield session
```
Route usage:
@@ -72,8 +72,8 @@ router = APIRouter()
@router.post("/items")
async def create_item(session: AsyncSession = Depends(get_db_session)) -> dict:
async with session.begin():
# write operations here
...
# write operations here
...
return {"status": "ok"}
```
@@ -98,6 +98,12 @@ Notes:
- `expire_on_commit=False` is commonly preferred in asyncio applications to reduce accidental post-commit reload behavior.
- `AsyncSession.refresh()` is preferred over broad expiration patterns when state refresh is needed.
## SQLModel Alignment
- If using SQLModel, keep the same session ownership model: one `async_sessionmaker`, one `AsyncSession` per request/unit-of-work.
- SQLModel does not replace SQLAlchemy async lifecycle primitives; it complements model declaration and typed data handling.
- During migration, avoid mixed ad hoc patterns where some handlers create SQLAlchemy sessions directly while others use SQLModel-specific wrappers.
---
## Concurrency Rules
@@ -0,0 +1,123 @@
# SQLModel Adoption and Boundaries
!!! info "Primary sources"
- [SQLModel documentation](https://sqlmodel.tiangolo.com/)
- [SQLModel FastAPI session dependency tutorial](https://sqlmodel.tiangolo.com/tutorial/fastapi/session-with-dependency/)
- [SQLModel release notes](https://sqlmodel.tiangolo.com/release-notes/)
- [SQLAlchemy asyncio extension](https://docs.sqlalchemy.org/en/21/orm/extensions/asyncio.html)
??? abstract "Decision metadata"
- Status: adopted
- Decision level: advisory
- Applies to: api-runtime, workers, tests
- Last reviewed: 2026-06-26
---
## Purpose
Define when and how to use SQLModel in an async FastAPI + SQLAlchemy modernization effort.
The goal is pragmatic adoption: use SQLModel where it reduces model duplication and improves typing ergonomics, without disrupting established async engine/session lifecycle rules.
---
## Scope and Non-Goals
- In scope: model-layer decisions, integration boundaries, phased adoption strategy.
- Out of scope: full framework rewrites and all-at-once model migration.
---
## Rules
- Keep SQLAlchemy async primitives as the runtime base: `create_async_engine`, `async_sessionmaker`, and `AsyncSession`.
- Prefer SQLModel for new domain modules where table models and API schemas would otherwise be duplicated.
- Migrate by bounded module or feature area; do not force whole-repo conversion in one phase.
- Keep transaction and session ownership policies identical whether models are SQLAlchemy Declarative or SQLModel.
- Document explicit reasons when SQLModel is deferred for a module.
---
## Recommended Patterns
### Pattern A: Bounded module adoption
- Choose one feature slice (for example, billing, projects, or auth profile data).
- Introduce SQLModel models for that slice only.
- Keep unchanged modules on existing SQLAlchemy models until a dedicated migration phase.
### Pattern B: Data model split for API boundaries
Use distinct models for persistence and external contracts.
```python
from sqlmodel import Field, SQLModel
class UserBase(SQLModel):
email: str
display_name: str
class User(UserBase, table=True):
id: int | None = Field(default=None, primary_key=True)
class UserCreate(UserBase):
pass
class UserRead(UserBase):
id: int
```
### Pattern C: Keep async lifecycle unchanged
```python
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
engine = create_async_engine(settings.database_url, pool_pre_ping=True)
session_factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
```
---
## Interoperability Notes
- SQLModel is designed as a thin layer over SQLAlchemy and Pydantic, so mixed codebases are expected during migration.
- Prefer one query style per module to reduce cognitive overhead.
- Keep loader strategies explicit in async paths to avoid implicit I/O surprises.
---
## Anti-Patterns
- Treating SQLModel adoption as equivalent to async-session modernization.
- Rewriting all models at once without rollback checkpoints.
- Introducing SQLModel in handlers while keeping old global/shared session patterns.
- Mixing multiple query/session idioms within the same module without clear conventions.
---
## Operational Checks
- Modernized module documents whether it is SQLModel-first or SQLAlchemy-only.
- Session/transaction ownership remains consistent across both model styles.
- New model modules use explicit API boundary models where needed.
---
## Testing Checks
- Module-level tests verify CRUD semantics for adopted SQLModel models.
- API tests verify response/request model behavior for SQLModel-based endpoints.
- Regression tests confirm unchanged modules continue to function during phased rollout.
---
## Migration Notes
- Start with low-risk bounded domains.
- Expand only after validation of session lifecycle, transaction behavior, and endpoint correctness.
- Maintain a tracked backlog of deferred modules with rationale and planned phase.