Move to asyncpg instead of psycopg

.github/workflows/lint-test.yml

@@ -24,7 +24,7 @@ jobs:
       PRE_COMMIT_HOME: ${{ github.workspace }}/.cache/pre-commit-cache
 
       AUTH_TOKEN: ci-token
-      DATABASE_URL: postgres://pysite:pysite@postgres:5432/pysite
+      DATABASE_URL: postgresql+asyncpg://pysite:pysite@postgres:5432/pysite
 
     # Via https://github.com/actions/example-services/blob/main/.github/workflows/postgres-service.yml
     # services:

README.md

@@ -24,3 +24,8 @@ If you want to propose new features for this API, please open an issue in the Is
 The easiest way to set up a development environment is by using [`poetry`](https://python-poetry.org/). After installing `poetry`, simply run `poetry install` in the root of the cloned repository to set up a virtual environment with our development toolkit installed.
 
 Another option is by using [Docker](https://www.docker.com/). After installing Docker on your machine, you should be able to run the API with `docker compose up`. For older versions of Docker, you may have to install `docker-compose` separately and run `docker-compose up` instead. This should spin up a container that automatically reloads the API if you change one of the files.
+
+### Generating a migration file
+With the project running in docker, open another terminal and run `poetry run task revision "Migration message here."`
+
+This will create a migration file in the path `alembic/versions`. Make sure to check it over, and fix any linting issues.

alembic/env.py

@@ -1,8 +1,10 @@
+import asyncio
 from logging.config import fileConfig
 
 from alembic import context
-from sqlalchemy import engine_from_config
-from sqlalchemy import pool
+from sqlalchemy import engine_from_config, pool
+from sqlalchemy.ext.asyncio import AsyncEngine
+from sqlalchemy.ext.asyncio.engine import AsyncConnection
 
 # This is a required step by Alembic to properly generate migrations
 import api.core.database.models  # noqa: F401
@@ -46,28 +48,40 @@ def run_migrations_offline() -> None:
         context.run_migrations()
 
 
-def run_migrations_online() -> None:
+def do_run_migrations(connection: AsyncConnection):
+    """Run all migrations on the given connection."""
+    context.configure(
+        connection=connection,
+        target_metadata=target_metadata,
+        compare_type=True,
+        compare_server_default=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_migrations_online():
     """
     Run migrations in 'online' mode.
 
     In this scenario we need to create an Engine
     and associate a connection with the context.
-
     """
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section),
-        prefix="sqlalchemy.",
-        poolclass=pool.NullPool,
+    connectable = AsyncEngine(
+        engine_from_config(
+            config.get_section(config.config_ini_section),
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+            future=True,
+        )
     )
 
-    with connectable.connect() as connection:
-        context.configure(connection=connection, target_metadata=target_metadata)
-
-        with context.begin_transaction():
-            context.run_migrations()
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
 
 
 if context.is_offline_mode():
     run_migrations_offline()
 else:
-    run_migrations_online()
+    asyncio.run(run_migrations_online())

alembic/script.py.mako

@@ -5,10 +5,9 @@ Revises: ${down_revision | comma,n}
 Create Date: ${create_date}
 
 """
-from alembic import op
 import sqlalchemy as sa
+from alembic import op
 ${imports if imports else ""}
-
 # revision identifiers, used by Alembic.
 revision = ${repr(up_revision)}
 down_revision = ${repr(down_revision)}
@@ -17,8 +16,10 @@ depends_on = ${repr(depends_on)}
 
 
 def upgrade():
+    """Upgrade the connected DB to this revision."""
     ${upgrades if upgrades else "pass"}
 
 
 def downgrade():
+    """Downgrade the connected DB to the previous revision."""
     ${downgrades if downgrades else "pass"}

api/core/database/models/api/bot/user.py

@@ -14,7 +14,6 @@
 
 from api.core.database import Base
 from api.core.settings import settings
-from .role import Role
 
 engine = create_engine(settings.database_url)
 SessionLocal = sessionmaker(bind=engine)
@@ -59,11 +58,8 @@ def validate_discriminator(
 
     @validates("roles")
     def validate_roles(self, _key: str, roles: list[int]) -> Union[list[int], NoReturn]:
-        """Raise ValueError if the provided role(s) is negative or non-existent."""
-        session = SessionLocal()
+        """Raise ValueError if the provided role(s) is negative."""
         for role in roles:
             if role < 0:
                 raise ValueError("Role IDs cannot be negative")
-            if not session.query(Role).filter_by(id=role).first():
-                raise ValueError(f"Role with ID {role} does not exist")
         return roles

api/core/settings.py

@@ -13,6 +13,12 @@
 from pydantic import BaseSettings, PostgresDsn
 
 
+class AsyncPostgresDsn(PostgresDsn):
+    """Extension of Pydantic's PostgresDsn to only allow the "+asyncpg" schema."""
+
+    allowed_schemes = {"postgresql+asyncpg"}
+
+
 class Settings(BaseSettings):
     """
     A Settings class that will parse env variables.
@@ -27,7 +33,7 @@ class Settings(BaseSettings):
     `pydantic.error_wrappers.ValidationError` exception.
     """
 
-    database_url: PostgresDsn
+    database_url: AsyncPostgresDsn
     auth_token: str
     commit_sha: str = "development"
     DEBUG: bool = False

docker-compose.yaml

@@ -26,7 +26,8 @@ services:
     tty: true
     volumes:
       - .:/app:ro
+      - ./alembic/versions:/app/alembic/versions
     environment:
-      database_url: postgresql://pysite:pysite@postgres:5432/pysite
+      database_url: postgresql+asyncpg://pysite:pysite@postgres:5432/pysite
       auth_token: "my_token"
       debug: 1