feat: enhance error handling and configuration validation

- Added a global exception handler to log unhandled exceptions and return a generic 500 JSON response without exposing details to the client.
- Updated the configuration to validate the `DATABASE_URL` format, ensuring it starts with `sqlite://` or `postgresql://`, and log warnings for invalid formats.
- Introduced safe parsing for numeric environment variables (`HTTP_PORT`, `INIT_DATA_MAX_AGE_SECONDS`) with defaults on invalid values, including logging warnings for out-of-range values.
- Enhanced the duty schedule parser to enforce limits on the number of schedule rows and the length of full names and duty strings, raising appropriate errors when exceeded.
- Updated internationalization messages to include generic error responses for import failures and parsing issues, improving user experience.
- Added unit tests to verify the new error handling and configuration validation behaviors.

duty_teller/run.py

@@ -3,7 +3,9 @@
 import asyncio
 import json
 import logging
+import sys
 import threading
+import time
 import urllib.request
 
 from telegram.ext import ApplicationBuilder
@@ -13,6 +15,9 @@ from duty_teller.config import require_bot_token
 from duty_teller.handlers import group_duty_pin, register_handlers
 from duty_teller.utils.http_client import safe_urlopen
 
+# Seconds to wait for HTTP server to bind before health check.
+_HTTP_STARTUP_WAIT_SEC = 3
+
 
 async def _resolve_bot_username(application) -> None:
     """If BOT_USERNAME is not set from env, resolve it via get_me()."""
@@ -69,6 +74,25 @@ def _run_uvicorn(web_app, port: int) -> None:
     loop.run_until_complete(server.serve())
 
 
+def _wait_for_http_ready(port: int) -> bool:
+    """Return True if /health responds successfully within _HTTP_STARTUP_WAIT_SEC."""
+    host = config.HTTP_HOST
+    if host == "0.0.0.0":
+        host = "127.0.0.1"
+    url = f"http://{host}:{port}/health"
+    deadline = time.monotonic() + _HTTP_STARTUP_WAIT_SEC
+    while time.monotonic() < deadline:
+        try:
+            req = urllib.request.Request(url)
+            with safe_urlopen(req, timeout=2) as resp:
+                if resp.status == 200:
+                    return True
+        except Exception as e:
+            logger.debug("Health check not ready yet: %s", e)
+        time.sleep(0.5)
+    return False
+
+
 def main() -> None:
     """Build the bot and FastAPI, start uvicorn in a thread, run polling."""
     require_bot_token()
@@ -85,16 +109,30 @@ def main() -> None:
 
     from duty_teller.api.app import app as web_app
 
-    t = threading.Thread(
-        target=_run_uvicorn,
-        args=(web_app, config.HTTP_PORT),
-        daemon=True,
-    )
-    t.start()
-
     if config.MINI_APP_SKIP_AUTH:
         logger.warning(
             "MINI_APP_SKIP_AUTH is set — API auth disabled (insecure); use only for dev"
         )
+        if config.HTTP_HOST not in ("127.0.0.1", "localhost", ""):
+            print(
+                "ERROR: MINI_APP_SKIP_AUTH must not be used in production (non-localhost).",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+
+    t = threading.Thread(
+        target=_run_uvicorn,
+        args=(web_app, config.HTTP_PORT),
+        daemon=False,
+    )
+    t.start()
+
+    if not _wait_for_http_ready(config.HTTP_PORT):
+        logger.error(
+            "HTTP server did not become ready on port %s within %s s; check port and permissions.",
+            config.HTTP_PORT,
+            _HTTP_STARTUP_WAIT_SEC,
+        )
+        sys.exit(1)
     logger.info("Bot starting (polling)... HTTP API on port %s", config.HTTP_PORT)
     app.run_polling(allowed_updates=["message", "my_chat_member"])