♻️ Simplify optional environment configuration (#2417)

## AI Disclaimer

Using Codex with gpt-5.6-sol. Reviewed manually.

.env

@@ -10,17 +10,12 @@ ENVIRONMENT=local
 
 PROJECT_NAME="Full Stack FastAPI Project"
 
-# Backend
-# Additional allowed CORS origins, separated by commas
-BACKEND_CORS_ORIGINS=
 SECRET_KEY=changethis
 FIRST_SUPERUSER=admin@example.com
 FIRST_SUPERUSER_PASSWORD=changethis
 
 # Emails
 SMTP_HOST=localhost
-SMTP_USER=
-SMTP_PASSWORD=
 EMAILS_FROM_EMAIL=info@example.com
 SMTP_TLS=False
 SMTP_PORT=1025
@@ -30,5 +25,3 @@ POSTGRES_SERVER=localhost
 POSTGRES_DB=app
 POSTGRES_USER=postgres
 POSTGRES_PASSWORD=changethis
-
-SENTRY_DSN=

.github/workflows/deploy-production.yml

@@ -17,7 +17,6 @@ jobs:
       - self-hosted
       - production
     env:
-      ENVIRONMENT: production
       DOMAIN: ${{ secrets.DOMAIN }}
       SECRET_KEY: ${{ secrets.SECRET_KEY }}
       FIRST_SUPERUSER: ${{ secrets.FIRST_SUPERUSER }}

.github/workflows/deploy-staging.yml

@@ -17,7 +17,6 @@ jobs:
       - self-hosted
       - staging
     env:
-      ENVIRONMENT: staging
       DOMAIN: ${{ secrets.DOMAIN }}
       SECRET_KEY: ${{ secrets.SECRET_KEY }}
       FIRST_SUPERUSER: ${{ secrets.FIRST_SUPERUSER }}

backend/app/core/config.py

@@ -34,7 +34,7 @@ class Settings(BaseSettings):
     # 60 minutes * 24 hours * 8 days = 8 days
     ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 8
     FRONTEND_HOST: str = "http://localhost:5173"
-    ENVIRONMENT: Literal["local", "staging", "production"] = "local"
+    ENVIRONMENT: Literal["local"] | None = None
 
     BACKEND_CORS_ORIGINS: Annotated[
         list[AnyUrl] | str, BeforeValidator(parse_cors)

compose.override.yml

@@ -68,10 +68,15 @@ services:
     volumes:
       - ./backend/htmlcov:/app/backend/htmlcov
     environment:
+      ENVIRONMENT: "local"
       SMTP_HOST: "mailcatcher"
       SMTP_PORT: "1025"
       SMTP_TLS: "false"
 
+  prestart:
+    environment:
+      ENVIRONMENT: "local"
+
   mailcatcher:
     image: schickling/mailcatcher
     ports:

compose.yml

@@ -57,21 +57,20 @@ services:
         condition: service_completed_successfully
     # The YAML anchor lets the prestart service reuse this environment mapping.
     environment: &backend-environment
-      ENVIRONMENT: ${ENVIRONMENT}
       PROJECT_NAME: ${PROJECT_NAME?Variable not set}
-      BACKEND_CORS_ORIGINS: ${BACKEND_CORS_ORIGINS}
+      BACKEND_CORS_ORIGINS: ${BACKEND_CORS_ORIGINS:-}
       SECRET_KEY: ${SECRET_KEY?Variable not set}
       FIRST_SUPERUSER: ${FIRST_SUPERUSER?Variable not set}
       FIRST_SUPERUSER_PASSWORD: ${FIRST_SUPERUSER_PASSWORD?Variable not set}
       SMTP_HOST: ${SMTP_HOST}
-      SMTP_USER: ${SMTP_USER}
-      SMTP_PASSWORD: ${SMTP_PASSWORD}
+      SMTP_USER: ${SMTP_USER:-}
+      SMTP_PASSWORD: ${SMTP_PASSWORD:-}
       EMAILS_FROM_EMAIL: ${EMAILS_FROM_EMAIL}
       POSTGRES_SERVER: db
       POSTGRES_DB: ${POSTGRES_DB}
       POSTGRES_USER: ${POSTGRES_USER?Variable not set}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD?Variable not set}
-      SENTRY_DSN: ${SENTRY_DSN}
+      SENTRY_DSN: ${SENTRY_DSN:-}
 
     healthcheck:
       test: ["CMD", "curl", "-f", "http://localhost:8000/api/v1/utils/health-check/"]

deployment.md

@@ -46,12 +46,6 @@ Copy the content and use that as password / secret key. And run that again to ge
 
 ### Required Environment Variables
 
-Set the `ENVIRONMENT`, by default `local` (for development), but when deploying to a server you would put something like `staging` or `production`:
-
-```bash
-export ENVIRONMENT=production
-```
-
 Set the `DOMAIN`, by default `localhost` (for development), but when deploying you would use your own domain, for example:
 
 ```bash