Simplify config module

Access to configuration values is now done through an instance of lazy
interface to typed environment variables, which allows not to update
this module every time a new variable is added (unless it must have a
default value). From now on, addition of new variables will be done
primarily just by appending them to .env.example.

Signed-off-by: alfred richardsn <rchrdsn@protonmail.ch>

.gitignore

@@ -1,6 +1,3 @@
-# Project files
-config.ini
-
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]

src/app.py

@@ -24,7 +24,7 @@
 from src import notifications
 from src.bot import dp
 from src.bot import tg
-from src.config import Config
+from src.config import config
 from src.escrow import connect_to_blockchains
 
 
@@ -34,7 +34,7 @@ async def on_startup(webhook_path, *args):
     Set webhook and run background tasks.
     """
     await tg.delete_webhook()
-    await tg.set_webhook("https://" + Config.SERVER_HOST + webhook_path)
+    await tg.set_webhook("https://" + config.SERVER_HOST + webhook_path)
     asyncio.create_task(notifications.run_loop())
     asyncio.create_task(connect_to_blockchains())
 
@@ -45,15 +45,15 @@ def main():
     Bot's main entry point.
     """
     url_token = secrets.token_urlsafe()
-    webhook_path = Config.WEBHOOK_PATH + "/" + url_token
+    webhook_path = config.WEBHOOK_PATH + "/" + url_token
 
     bot.setup()
     executor.start_webhook(
         dispatcher=dp,
         webhook_path=webhook_path,
         on_startup=lambda *args: on_startup(webhook_path, *args),
-        host=Config.INTERNAL_HOST,
-        port=Config.SERVER_PORT,
+        host=config.INTERNAL_HOST,
+        port=config.SERVER_PORT,
     )
     print()  # noqa: T001  Executor stopped with ^C
 

src/bot.py

@@ -23,7 +23,7 @@
 from aiogram.contrib.middlewares.logging import LoggingMiddleware
 from aiogram.dispatcher import Dispatcher
 
-from src.config import Config
+from src.config import config
 from src.database import MongoStorage
 from src.i18n import i18n
 
@@ -33,16 +33,16 @@
 
 
 def setup():
-    """Set API token from Config to bot and setup dispatcher."""
-    with open(Config.TOKEN_FILENAME, "r") as token_file:
+    """Set API token from config to bot and setup dispatcher."""
+    with open(config.TOKEN_FILENAME, "r") as token_file:
         tg._ctx_token.set(token_file.read().strip())
 
     dp.storage = MongoStorage()
 
     i18n.reload()
     dp.middleware.setup(i18n)
 
-    logging.basicConfig(level=Config.LOGGER_LEVEL)
+    logging.basicConfig(level=config.LOGGER_LEVEL)
     dp.middleware.setup(LoggingMiddleware())
 
 

src/config.py

@@ -17,58 +17,52 @@
 from os import getenv
 
 
-def getenv_int(key, default=None):
-    """Convert the value of the environment variable key to an integer."""
-    env = getenv(key)
-    try:
-        return int(env)
-    except (TypeError, ValueError):
-        return default
+DEFAULT_VALUES = {
+    "INTERNAL_HOST": "127.0.0.1",
+    "DATABASE_HOST": "127.0.0.1",
+    "DATABASE_PORT": 27017,
+    "DATABASE_NAME": "tellerbot",
+    "ESCROW_ENABLED": True,
+}
 
 
-def getenv_bool(key, default=None):
-    """Convert the value of the environment variable key to a boolean."""
+def get_typed_env(key):
+    """Get an environment variable with inferred type."""
     env = getenv(key)
-    return env == "true" if env in ("true", "false") else default
+    if env is None:
+        return None
+    elif env == "true":
+        return True
+    elif env == "false":
+        return False
+    try:
+        return int(env)
+    except ValueError:
+        return env
 
 
 class Config:
-    """Data holder for configuration values."""
-
-    TOKEN_FILENAME: str
-    INTERNAL_HOST: str = "127.0.0.1"
-    SERVER_HOST: str
-    SERVER_PORT: int
-    WEBHOOK_PATH: str
-    DATABASE_HOST: str = "127.0.0.1"
-    DATABASE_PORT: int = 27017
-    DATABASE_USERNAME: str
-    DATABASE_PASSWORD_FILENAME: str
-    DATABASE_NAME: str = "tellerbot"
-
-    LOGGER_LEVEL: str
-    LOG_FILENAME: str
+    """Lazy interface to configuration values."""
 
-    SUPPORT_CHAT_ID: int
-    EXCEPTIONS_CHAT_ID: int
+    def __setattr__(self, name, value):
+        """Set configuration value."""
+        super().__setattr__(name, value)
 
-    ORDERS_COUNT: int
-    ORDERS_LIMIT_HOURS: int
-    ORDERS_LIMIT_COUNT: int
-    ORDER_DURATION_LIMIT: int
+    def __getattr__(self, name):
+        """Get configuration value.
 
-    ESCROW_FEE_PERCENTS: int
-    ESCROW_ENABLED: bool = True
-    WIF_FILENAME: str
-    OP_CHECK_TIMEOUT_HOURS: int
+        Return value of environment variable ``name`` if it is set or
+        default value otherwise.
+        """
+        env = get_typed_env(name)
+        if env is not None:
+            value = env
+        elif name not in DEFAULT_VALUES:
+            raise AttributeError(f"config has no option '{name}'")
+        else:
+            value = DEFAULT_VALUES[name]
+        setattr(self, name, value)
+        return value
 
 
-for name, annotation in Config.__annotations__.items():
-    if annotation == int:
-        value = getenv_int(name)
-    elif annotation == bool:
-        value = getenv_bool(name)
-    else:
-        value = getenv(name)
-    if value is not None:
-        setattr(Config, name, value)
+config = Config()

src/database.py

@@ -19,20 +19,20 @@
 from aiogram.dispatcher.storage import BaseStorage
 from motor.motor_asyncio import AsyncIOMotorClient
 
-from src.config import Config
+from src.config import config
 
 
 try:
-    with open(Config.DATABASE_PASSWORD_FILENAME, "r") as password_file:
+    with open(config.DATABASE_PASSWORD_FILENAME, "r") as password_file:
         client = AsyncIOMotorClient(
-            Config.DATABASE_HOST,
-            Config.DATABASE_PORT,
-            username=Config.DATABASE_USERNAME,
+            config.DATABASE_HOST,
+            config.DATABASE_PORT,
+            username=config.DATABASE_USERNAME,
             password=password_file.read(),
         )
 except (AttributeError, FileNotFoundError):
-    client = AsyncIOMotorClient(Config.DATABASE_HOST)
-database = client[Config.DATABASE_NAME]
+    client = AsyncIOMotorClient(config.DATABASE_HOST)
+database = client[config.DATABASE_NAME]
 
 STATE_KEY = "state"
 

src/escrow/__init__.py

@@ -14,10 +14,10 @@
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with TellerBot.  If not, see <https://www.gnu.org/licenses/>.
-from src.config import Config
+from src.config import config
 
 
-if Config.ESCROW_ENABLED:
+if config.ESCROW_ENABLED:
     from src.escrow.blockchain.golos_blockchain import GolosBlockchain
 
     SUPPORTED_BLOCKCHAINS = [GolosBlockchain()]

src/escrow/blockchain/golos_blockchain.py

@@ -30,7 +30,7 @@
 from golos.exceptions import TransactionNotFound
 from golos.ws_client import error_handler
 
-from src.config import Config
+from src.config import config
 from src.database import database
 from src.escrow.blockchain import BaseBlockchain
 from src.escrow.blockchain import BlockchainConnectionError
@@ -115,7 +115,7 @@ async def get_limits(self, asset: str):
         return limits.get(asset)
 
     async def transfer(self, to: str, amount: Decimal, asset: str, memo: str = ""):
-        with open(Config.WIF_FILENAME) as wif_file:
+        with open(config.WIF_FILENAME) as wif_file:
             transaction = await get_running_loop().run_in_executor(
                 None,
                 self._golos.transfer,

src/handlers/__init__.py

@@ -25,7 +25,7 @@
 
 from src.bot import dp
 from src.bot import tg
-from src.config import Config
+from src.config import config
 from src.handlers import escrow  # noqa: F401, noreorder
 from src.handlers import start_menu  # noqa: F401, noreorder
 from src.handlers import creation  # noqa: F401
@@ -80,7 +80,7 @@ async def errors_handler(update: types.Update, exception: Exception):
 
     if chat_id is not None:
         try:
-            exceptions_chat_id = Config.EXCEPTIONS_CHAT_ID
+            exceptions_chat_id = config.EXCEPTIONS_CHAT_ID
         except AttributeError:
             pass
         else:

src/handlers/base.py

@@ -25,7 +25,7 @@
 from aiogram.utils.emoji import emojize
 from pymongo.cursor import Cursor
 
-from src.config import Config
+from src.config import config
 from src.escrow import get_escrow_instance
 
 from src.bot import (  # noqa: F401, noreorder
@@ -110,19 +110,19 @@ async def orders_list(
             {"_id": user["_id"]}, {"$set": {"invert_book": invert}}
         )
 
-    keyboard = types.InlineKeyboardMarkup(row_width=min(Config.ORDERS_COUNT // 2, 8))
+    keyboard = types.InlineKeyboardMarkup(row_width=min(config.ORDERS_COUNT // 2, 8))
 
     inline_orders_buttons = (
         types.InlineKeyboardButton(
             emojize(":arrow_left:"),
             callback_data="{} {} {}".format(
-                buttons_data, start - Config.ORDERS_COUNT, int(invert)
+                buttons_data, start - config.ORDERS_COUNT, int(invert)
             ),
         ),
         types.InlineKeyboardButton(
             emojize(":arrow_right:"),
             callback_data="{} {} {}".format(
-                buttons_data, start + Config.ORDERS_COUNT, int(invert)
+                buttons_data, start + config.ORDERS_COUNT, int(invert)
             ),
         ),
     )
@@ -136,7 +136,7 @@ async def orders_list(
             await tg.edit_message_text(text, chat_id, message_id, reply_markup=keyboard)
         return
 
-    all_orders = await cursor.to_list(length=start + Config.ORDERS_COUNT)
+    all_orders = await cursor.to_list(length=start + config.ORDERS_COUNT)
     orders = all_orders[start:]
 
     lines = []
@@ -197,8 +197,8 @@ async def orders_list(
     text = (
         "\\["
         + i18n("page {number} {total}").format(
-            number=math.ceil(start / Config.ORDERS_COUNT) + 1,
-            total=math.ceil(quantity / Config.ORDERS_COUNT),
+            number=math.ceil(start / config.ORDERS_COUNT) + 1,
+            total=math.ceil(quantity / config.ORDERS_COUNT),
         )
         + "]\n"
         + "\n".join(lines)

src/handlers/creation.py

@@ -44,7 +44,7 @@
 from src import whitelist
 from src.bot import dp
 from src.bot import tg
-from src.config import Config
+from src.config import config
 from src.database import database
 from src.handlers.base import inline_control_buttons
 from src.handlers.base import private_handler
@@ -244,14 +244,14 @@ async def whitelisting_request(call: types.CallbackQuery):
                 currency, len(request["users"]) + 1
             )
             if len(request["users"]) == 1:
-                message = await tg.send_message(Config.SUPPORT_CHAT_ID, support_text)
+                message = await tg.send_message(config.SUPPORT_CHAT_ID, support_text)
                 await database.whitelisting_requests.update_one(
                     {"_id": request["_id"]},
                     {"$set": {"message_id": message.message_id}},
                 )
             else:
                 await tg.edit_message_text(
-                    support_text, Config.SUPPORT_CHAT_ID, request["message_id"],
+                    support_text, config.SUPPORT_CHAT_ID, request["message_id"],
                 )
 
     await call.answer()
@@ -668,7 +668,7 @@ async def text_location(message: types.Message, state: FSMContext):
         await OrderCreation.duration.set()
         await tg.send_message(
             message.chat.id,
-            i18n("ask_duration {limit}").format(limit=Config.ORDER_DURATION_LIMIT),
+            i18n("ask_duration {limit}").format(limit=config.ORDER_DURATION_LIMIT),
             reply_markup=InlineKeyboardMarkup(
                 inline_keyboard=await inline_control_buttons()
             ),
@@ -718,7 +718,7 @@ async def choose_location(message: types.Message, state: FSMContext):
     await OrderCreation.duration.set()
     await tg.send_message(
         message.chat.id,
-        i18n("ask_duration {limit}").format(limit=Config.ORDER_DURATION_LIMIT),
+        i18n("ask_duration {limit}").format(limit=config.ORDER_DURATION_LIMIT),
         reply_markup=InlineKeyboardMarkup(
             inline_keyboard=await inline_control_buttons()
         ),
@@ -729,7 +729,7 @@ async def choose_location(message: types.Message, state: FSMContext):
 async def duration_handler(call: types.CallbackQuery):
     """Ask for duration."""
     await tg.edit_message_text(
-        i18n("ask_duration {limit}").format(limit=Config.ORDER_DURATION_LIMIT),
+        i18n("ask_duration {limit}").format(limit=config.ORDER_DURATION_LIMIT),
         call.message.chat.id,
         call.message.message_id,
         reply_markup=InlineKeyboardMarkup(
@@ -749,11 +749,11 @@ async def choose_duration(message: types.Message, state: FSMContext):
         await tg.send_message(message.chat.id, i18n("send_natural_number"))
         return
 
-    if duration > Config.ORDER_DURATION_LIMIT:
+    if duration > config.ORDER_DURATION_LIMIT:
         await tg.send_message(
             message.chat.id,
             i18n("exceeded_duration_limit {limit}").format(
-                limit=Config.ORDER_DURATION_LIMIT
+                limit=config.ORDER_DURATION_LIMIT
             ),
         )
         return
@@ -776,7 +776,7 @@ async def set_order(order: MutableMapping[str, Any], chat_id: int):
     """Set missing values and finish order creation."""
     order["start_time"] = time()
     if "duration" not in order:
-        order["duration"] = Config.ORDER_DURATION_LIMIT
+        order["duration"] = config.ORDER_DURATION_LIMIT
     order["expiration_time"] = time() + order["duration"] * 24 * 60 * 60
     order["notify"] = True
     if "price_sell" not in order and "sum_buy" in order and "sum_sell" in order: