Handle config not set cases more gracefully

config.py

@@ -1,7 +1,7 @@
 import logging
 
 from etcd3_wrapper import Etcd3Wrapper
-from decouple import config
+from decouple import config, UndefinedValueError
 
 logging.basicConfig(
     level=logging.DEBUG,
@@ -11,7 +11,11 @@ logging.basicConfig(
     datefmt='%Y-%m-%d:%H:%M:%S',
 )
 
-
-etcd_client = Etcd3Wrapper(host=config("ETCD_HOST"), port=config("ETCD_PORT"))
+# load configs
 APP_PORT = config("APP_PORT", 5000)
+try:
+    etcd_client = Etcd3Wrapper(host=config("ETCD_HOST"), port=config("ETCD_PORT"))
     STRIPE_API_PRIVATE_KEY = config("STRIPE_API_PRIVATE_KEY")
+except UndefinedValueError as uve:
+    print(str(uve))
+    exit(1)

ucloud_pay.py

@@ -2,7 +2,7 @@ import binascii
 import json
 
 import requests
-from decouple import config, Csv
+from decouple import config, Csv, UndefinedValueError
 from datetime import datetime
 from flask import Flask, request
 from flask_restful import Resource, Api
@@ -16,13 +16,26 @@ import time
 app = Flask(__name__)
 api = Api(app)
 
+# load configs
+AUTH_NAME = config("AUTH_NAME", "")
+AUTH_TOKEN = TOTP(config("AUTH_SEED", "")).now()
+AUTH_REALM = config("AUTH_REALM", "")
+OTP_SERVER = config("OTP_SERVER", "")
+OTP_VERIFY_ENDPOINT = config("OTP_VERIFY_ENDPOINT", "verify/")
+
+try:
+    INIT_ORDER_ID = config("INIT_ORDER_ID")
+    REALM_ALLOWED = config("REALM_ALLOWED", cast=Csv(str))
+except UndefinedValueError as uve:
+    print(str(uve))
+    exit(1)
 
 def check_otp(name, realm, token):
     try:
         data = {
-            "auth_name": config("AUTH_NAME", ""),
-            "auth_token": TOTP(config("AUTH_SEED", "")).now(),
-            "auth_realm": config("AUTH_REALM", ""),
+            "auth_name": AUTH_NAME,
+            "auth_token": AUTH_TOKEN,
+            "auth_realm": AUTH_REALM,
             "name": name,
             "realm": realm,
             "token": token,
@@ -32,8 +45,8 @@ def check_otp(name, realm, token):
 
     response = requests.post(
         "{OTP_SERVER}{OTP_VERIFY_ENDPOINT}".format(
-            OTP_SERVER=config("OTP_SERVER", ""),
-            OTP_VERIFY_ENDPOINT=config("OTP_VERIFY_ENDPOINT", "verify/"),
+            OTP_SERVER=OTP_SERVER,
+            OTP_VERIFY_ENDPOINT=OTP_VERIFY_ENDPOINT,
         ),
         data=data,
     )
@@ -50,7 +63,7 @@ def get_order_id():
     if order_id_kv is not None:
         order_id = int(order_id_kv.value) + 1
     else:
-        order_id = config("INIT_ORDER_ID")
+        order_id = INIT_ORDER_ID
     client.put("/v1/last_order_id", str(order_id))
     return "OR-{}".format(order_id)
 
@@ -97,7 +110,6 @@ class AddProduct(Resource):
     def post():
         data = request.json
         logging.debug("Got data: {}".format(str(data)))
-        REALM_ALLOWED = config("REALM_ALLOWED", cast=Csv(str))
         logging.debug("REALM_ALLOWED = {}".format(REALM_ALLOWED))
         if data["realm"] not in REALM_ALLOWED:
             logging.error(