Unified logging behaviour and added exponential backoff

- Logger doesn't start with log level DEBUG by default, instead reads a environment variable
- Secret handler raises exceptions instead of using the module os to exit
- Added extensive debug logging
- Added detailed function descriptions
- Added exponential backoff when parsing the RSS feed

src/main.py

@@ -2,7 +2,7 @@ from fastapi import FastAPI, Depends, HTTPException, Response, Request
 import uvicorn
 from contextlib import asynccontextmanager
 from db import get_db, create_connection_pool, close_connection_pool, start_healthcheck_thread
-from logger_handler import setup_logger
+from logger_handler import setup_logger, LOG_LEVEL
 from feed_handler import grab_latest_chapter_information
 from send_notification import send_notification
 from metrics_server import REQUEST_COUNTER
@@ -14,17 +14,18 @@ logger = setup_logger(__name__)
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-	logger.info("Starting application...")
+	logger.info("[App] Starting application...")
 
-	logger.info("Creating MySQL connection pool...")
+	logger.info("[DB] Creating MySQL connection pool...")
 	create_connection_pool()
 
 	start_healthcheck_thread()
-	logger.info("MySQL healthcheck thread started.")
+	logger.info("[DB] MySQL healthcheck thread started.")
 
 	yield
-	logger.info("Closing MySQL connection pool...")
+	logger.info("[App] Closing MySQL connection pool...")
 	close_connection_pool()
+	logger.info("[App] Shutdown complete.")
 
 api = FastAPI(
 		title="Docker Repository Query",
@@ -35,50 +36,73 @@ api = FastAPI(
 
 @api.middleware("http")
 async def prometheus_middleware(request: Request, call_next):
+	logger.debug(f"[Metrics] Incoming request: {request.method} {request.url.path}")
 	status = 500
 	try:
 		response = await call_next(request)
 		status = response.status_code
+		logger.debug(f"[Metrics] Request processed with status {status}")
 	except Exception:
+		logger.error(f"[Metrics] Exception occurred: {e}", exc_info=True)
 		raise
 	finally:
 		REQUEST_COUNTER.labels(request.method, request.url.path, status).inc()
+		logger.debug(f"[Metrics] Counter incremented for {request.method} {request.url.path} [{status}]")
 	return response
 
-
-@api.get("/health")
-def return_health():
-	return Response(status_code=200)
-
 @api.get("/royalroad")
-def get_chapters(
-			request: Request,
-			db = Depends(get_db)
-			):
-	try:
-		logger.info("Checking for new Royalroad chapters")
+def get_chapters(request: Request, db = Depends(get_db)):
+	"""
+	Checks for new Royalroad chapters and updates the database accordingly.
 
+	Behaviour:
+		- Fetches all active stories and their last known chapter number.
+		- Queries Royalroad for each story's latest chapter.
+		- Updates `lastChapter` if a new chapter is found.
+		- Sends a notification for any newly discovered chapters.
+
+	Returns:
+		A JSON object indicating the check status.
+	"""
+	logger.info("[Royalroad] Checking for new chapters...")
+	try:
 		cursor = db.cursor()
-		cursor.execute("SELECT id,royalroadId,lastChapter FROM stories where active=1")
-		for id,royalroadId,last_chapter_db in cursor.fetchall():
-			chapter_number,chapter_link,title = grab_latest_chapter_information(royalroadId)
+		cursor.execute("SELECT id, royalroadId, lastChapter FROM stories WHERE active=1")
+
+		stories = cursor.fetchall()
+		logger.debug(f"[Royalroad] Found {len(stories)} active stories to check.")
+
+		for id, royalroadId, last_chapter_db in stories:
+			chapter_number, chapter_link, story_title = grab_latest_chapter_information(royalroadId)
+			logger.debug(f"[Royalroad] Story {id}: last={last_chapter_db}, latest={chapter_number}")
+
 			if chapter_number > last_chapter_db:
-				cursor.execute("UPDATE stories SET lastChapter = %s WHERE id = %s",
-								(chapter_number, id))
+				logger.info(f"[Royalroad] New chapter detected for story ID {id}: {story_title}")
+				cursor.execute("UPDATE stories SET lastChapter = %s WHERE id = %s", (chapter_number, id))
 				db.commit()
-				send_notification(title,chapter_number,chapter_link)
+				send_notification(story_title, chapter_number, chapter_link)
+				logger.debug(f"[Royalroad] Notification sent for story ID {id}")
+
+		logger.info("[Royalroad] Chapter check completed successfully.")
 		return {"status": "checked"}
+	except ValueError as e:
+		logger.error(f"[Royalroad] Failed to fetch feed {royalroadId}: {e}")
+		raise HTTPException(status_code=404, detail=str(e))
+
 	except Exception as e:
+		logger.error(f"[Royalroad] Error during chapter check: {e}", exc_info=True)
 		raise HTTPException(status_code=500, detail=str(e))
 
 async def start_servers():
-	config_main = uvicorn.Config("main:api", host="0.0.0.0", port=5000, log_level="info")
-	config_metrics = uvicorn.Config("metrics_server:metrics_api", host="0.0.0.0", port=9000, log_level="info")
+	logger.info("[Server] Starting main API (port 5000) and metrics server (port 9000)...")
+	config_main = uvicorn.Config("main:api", host="0.0.0.0", port=5000, log_level=LOG_LEVEL.lower())
+	config_metrics = uvicorn.Config("metrics_server:metrics_api", host="0.0.0.0", port=9000, log_level=LOG_LEVEL.lower())
 
 	server_main = uvicorn.Server(config_main)
 	server_metrics = uvicorn.Server(config_metrics)
 
 	await asyncio.gather(server_main.serve(), server_metrics.serve())
+	logger.info("[Server] Both servers started successfully.")
 
 if __name__ == "__main__":
 	asyncio.run(start_servers())