📝 Add documentation about settings and env vars (#1118)

* Add doc and example for env var config

* Syntax highlight for .env file

* Add test for configuration docs

* 📝 Update settings docs, add more examples

* ✅ Add tests for settings

* 🚚 Rename "Application Configuration" to "Metadata and Docs URLs"

to disambiguate between that and settings

* 🔥 Remove replaced example file

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

docs_src/settings/app01/config.py

@@ -0,0 +1,10 @@
+from pydantic import BaseSettings
+
+
+class Settings(BaseSettings):
+    app_name: str = "Awesome API"
+    admin_email: str
+    items_per_user: int = 50
+
+
+settings = Settings()

docs_src/settings/app01/main.py

@@ -0,0 +1,14 @@
+from fastapi import FastAPI
+
+from . import config
+
+app = FastAPI()
+
+
+@app.get("/info")
+async def info():
+    return {
+        "app_name": config.settings.app_name,
+        "admin_email": config.settings.admin_email,
+        "items_per_user": config.settings.items_per_user,
+    }

docs_src/settings/app02/config.py

@@ -0,0 +1,10 @@
+from pydantic import BaseSettings
+
+
+class Settings(BaseSettings):
+    app_name: str = "Awesome API"
+    admin_email: str
+    items_per_user: int = 50
+
+
+settings: Settings = None

docs_src/settings/app02/main.py

@@ -0,0 +1,21 @@
+from fastapi import Depends, FastAPI
+
+from . import config
+
+app = FastAPI()
+
+
+def get_settings():
+    if config.settings:
+        return config.settings
+    config.settings = config.Settings()
+    return config.settings
+
+
+@app.get("/info")
+async def info(settings: config.Settings = Depends(get_settings)):
+    return {
+        "app_name": settings.app_name,
+        "admin_email": settings.admin_email,
+        "items_per_user": settings.items_per_user,
+    }

docs_src/settings/app02/test_main.py

@@ -0,0 +1,23 @@
+from fastapi.testclient import TestClient
+
+from . import config, main
+
+client = TestClient(main.app)
+
+
+def get_settings_override():
+    return config.Settings(admin_email="testing_admin@example.com")
+
+
+main.app.dependency_overrides[main.get_settings] = get_settings_override
+
+
+def test_app():
+
+    response = client.get("/info")
+    data = response.json()
+    assert data == {
+        "app_name": "Awesome API",
+        "admin_email": "testing_admin@example.com",
+        "items_per_user": 50,
+    }

docs_src/settings/app03/config.py

@@ -0,0 +1,13 @@
+from pydantic import BaseSettings
+
+
+class Settings(BaseSettings):
+    app_name: str = "Awesome API"
+    admin_email: str
+    items_per_user: int = 50
+
+    class Config:
+        env_file = ".env"
+
+
+settings: Settings = None

docs_src/settings/app03/main.py

@@ -0,0 +1,21 @@
+from fastapi import Depends, FastAPI
+
+from . import config
+
+app = FastAPI()
+
+
+def get_settings():
+    if config.settings:
+        return config.settings
+    config.settings = config.Settings()
+    return config.settings
+
+
+@app.get("/info")
+async def info(settings: config.Settings = Depends(get_settings)):
+    return {
+        "app_name": settings.app_name,
+        "admin_email": settings.admin_email,
+        "items_per_user": settings.items_per_user,
+    }

docs_src/settings/tutorial001.py

@@ -0,0 +1,21 @@
+from fastapi import FastAPI
+from pydantic import BaseSettings
+
+
+class Settings(BaseSettings):
+    app_name: str = "Awesome API"
+    admin_email: str
+    items_per_user: int = 50
+
+
+settings = Settings()
+app = FastAPI()
+
+
+@app.get("/info")
+async def info():
+    return {
+        "app_name": settings.app_name,
+        "admin_email": settings.admin_email,
+        "items_per_user": settings.items_per_user,
+    }