use pydantic for config managment

Pipfile

@@ -27,8 +27,8 @@ dataclasses = {version = "*",markers = "python_version<'3.7'"}
 fastapi = "*"
 gunicorn = "*"
 idna_ssl = {version = "*",markers = "python_version<'3.7'"}
+pydantic = {extras = ["dotenv"],version = "*"}
 python-dateutil = "*"
-python-dotenv = "*"
 requests = "*"
 uvicorn = "*"
 

app/config.py

@@ -0,0 +1,27 @@
+"""app.config.py"""
+import functools
+import logging
+
+import pydantic
+
+CFG_LOGGER = logging.getLogger("app.config")
+
+
+class _Settings(pydantic.BaseSettings):
+    port: int = 5000
+
+
+@functools.lru_cache()
+def get_settings(**kwargs):
+    """
+    Read settings from the environment or `.env` file.
+    https://pydantic-docs.helpmanual.io/usage/settings/#dotenv-env-support
+
+    Usage:
+        import app.config
+
+        settings = app.config.get_settings(_env_file="")
+        port_number = settings.port
+    """
+    CFG_LOGGER.info("Loading Config settings from Environment ...")
+    return _Settings(**kwargs)

app/main.py

@@ -2,7 +2,6 @@
 app.main.py
 """
 import logging
-import os
 
 import pydantic
 import uvicorn
@@ -11,6 +10,7 @@
 from fastapi.middleware.gzip import GZipMiddleware
 from fastapi.responses import JSONResponse
 
+from .config import get_settings
 from .data import data_source
 from .routers import V1, V2
 from .utils.httputils import setup_client_session, teardown_client_session
@@ -20,6 +20,8 @@
 # ############
 LOGGER = logging.getLogger("api")
 
+SETTINGS = get_settings()
+
 APP = FastAPI(
     title="Coronavirus Tracker",
     description=(
@@ -93,5 +95,5 @@ async def handle_validation_error(
 # Running of app.
 if __name__ == "__main__":
     uvicorn.run(
-        "app.main:APP", host="127.0.0.1", port=int(os.getenv("PORT", "5000")), log_level="info",
+        "app.main:APP", host="127.0.0.1", port=SETTINGS.port, log_level="info",
     )

requirements-dev.txt

@@ -31,13 +31,13 @@ pluggy==0.13.1
 py==1.8.1
 pylint==2.4.4
 pyparsing==2.4.7
-pytest-asyncio==0.10.0
+pytest-asyncio==0.11.0
 pytest-cov==2.8.1
 pytest==5.4.1
 pyyaml==5.3.1
 regex==2020.4.4
 requests==2.23.0
-responses==0.10.12
+responses==0.10.14
 six==1.14.0
 smmap==3.0.2
 stevedore==1.32.0

requirements.txt

@@ -15,7 +15,7 @@ httptools==0.1.1 ; sys_platform != 'win32' and sys_platform != 'cygwin' and plat
 idna-ssl==1.1.0 ; python_version < '3.7'
 idna==2.9
 multidict==4.7.5
-pydantic==1.5
+pydantic[dotenv]==1.5.1
 python-dateutil==2.8.1
 python-dotenv==0.13.0
 requests==2.23.0