Use pydantic-settings for app settings object

* Already using pydantic via FastAPI
* Less to maintain
* Typed settings - catches config errors

Author: andyhd

Makefile

@@ -96,6 +96,10 @@ else
 endif
 
 
+.PHONY: migrate-and-run
+migrate-and-run: migrations run
+
+
 ## docker-build: Build a Docker image
 .PHONY: docker-build
 docker-build: clean

client/src/GovSingleConsent.ts

@@ -83,10 +83,10 @@ export class GovSingleConsent {
         request(
           getConsentsUrl,
           { timeout: 1000 },
-          ({ status: consents }: { status: Consents }) => {
-            this.updateBrowserConsents(consents)
+          ({consent}) => {
+            this.updateBrowserConsents(consent)
             this._consentsUpdateCallback(
-              consents,
+              consent,
               GovSingleConsent.isConsentPreferencesSet(),
               null
             )

consent_api/__init__.py

@@ -6,7 +6,7 @@
 from fastapi_etag import add_exception_handler
 from starlette.middleware.sessions import SessionMiddleware
 
-from consent_api import config
+from consent_api.config import settings
 from consent_api.routers import consent
 from consent_api.routers import dummy_service
 from consent_api.routers import healthcheck
@@ -18,7 +18,7 @@
 
 @app.on_event("startup")
 async def startup_event():
-    if config.FLAG_FIXTURES:
+    if settings.flag_fixtures:
         await register_origins_for_e2e_testing()
 
 
@@ -28,7 +28,7 @@ async def startup_event():
 )
 app.add_middleware(
     SessionMiddleware,
-    secret_key=config.SECRET_KEY,
+    secret_key=settings.secret_key,
 )
 app.include_router(consent.router)
 app.include_router(healthcheck.router)

consent_api/commands/delete_expired_consent.py

@@ -7,7 +7,7 @@
 from sqlalchemy.sql.expression import delete
 from sqlmodel import col
 
-from consent_api import config
+from consent_api.config import settings
 from consent_api.database import engine
 from consent_api.models import UserConsent
 
@@ -18,7 +18,7 @@ async def delete_expired_consent():
         await conn.execute(
             delete(UserConsent).where(
                 col(UserConsent.updated_at)
-                < (datetime.now() - timedelta(days=config.CONSENT_EXPIRY_DAYS)),
+                < (datetime.now() - timedelta(days=settings.consent_expiry_days)),
             )
         )
     await engine.dispose()

consent_api/config.py

@@ -0,0 +1,52 @@
+"""App configuration."""
+import os
+
+from pydantic import Field
+from pydantic_settings import BaseSettings
+from pydantic_settings import SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    secret_key: bytes = os.urandom(24)
+    sqlalchemy_database_uri: str = Field(
+        alias="DATABASE_URL",
+        default="postgresql+asyncpg://localhost:5432/consent_api",
+    )
+    consent_expiry_days: int = 7
+    consent_api_origin: str | None = None
+    other_service_origin: str | None = None
+    flag_fixtures: bool = True
+
+    model_config = SettingsConfigDict(env_file=".env", extra="ignore")
+
+
+class Production(Settings):
+    ...
+
+
+class Staging(Settings):
+    consent_api_origin: str = "https://gds-single-consent-staging.app"
+
+
+class Testing(Settings):
+    consent_api_origin: str = "http://consent-api"
+    other_service_origin: str = "http://dummy-service-1"
+
+
+class Development(Settings):
+    ...
+
+
+def get_settings():
+    env = os.getenv("ENV", "development")
+    try:
+        return {subclass.__name__: subclass for subclass in Settings.__subclasses__()}[
+            env.title()
+        ]()
+    except KeyError as err:
+        raise ValueError(f"Invalid ENV={env}") from err
+
+
+settings = get_settings()
+
+print(f"Environment: {settings.__class__.__name__}")

consent_api/config/__init__.py

@@ -7,10 +7,10 @@
 from sqlalchemy.ext.asyncio import create_async_engine
 from sqlalchemy.orm import sessionmaker
 
-from consent_api import config
+from consent_api.config import settings
 
 engine = create_async_engine(
-    config.SQLALCHEMY_DATABASE_URI,
+    str(settings.sqlalchemy_database_uri),
     json_serializer=FriendlyEncoder().encode,
     pool_size=20,
     max_overflow=20,

consent_api/config/defaults.py

@@ -4,7 +4,7 @@
 import jinja2
 from starlette.templating import Jinja2Templates
 
-from consent_api.config import CONSENT_API_URL
+from consent_api.config import settings
 
 templates = Jinja2Templates(
     directory="consent_api/templates",  # required but overridden by loader arg
@@ -18,5 +18,5 @@
     ),
 )
 templates.env.globals.update(
-    {"CONSENT_API_URL": CONSENT_API_URL},
+    {"CONSENT_API_URL": f"{settings.consent_api_origin}/api/v1/consent/"},
 )

consent_api/database.py

@@ -5,14 +5,14 @@
 from fastapi import Request
 from starlette.responses import Response
 
-from consent_api import config
+from consent_api.config import settings
 from consent_api.jinja import templates
 
 router = APIRouter(include_in_schema=False)
 get = router.get
 
 DUMMY_SERVICE_PREFIX = "/dummy-service"
-OTHER_SERVICE_URL = f"{config.OTHER_SERVICE_ORIGIN}{DUMMY_SERVICE_PREFIX}/"
+OTHER_SERVICE_URL = f"{settings.other_service_origin}{DUMMY_SERVICE_PREFIX}/"
 
 
 @get("/")