feat(backend): enhance server shutdown process and Redis error handling

- Add 'init' flag to backend service in docker-compose for initialization.
- Modify start-dev.sh to use 'exec' for better process management.
- Set 'trust proxy' in app configuration for improved request handling.
- Update graceful shutdown to log connection closures for Prisma, Redis, and IORedis.
- Change signal handling to 'once' for shutdown events in app and worker.
- Improve Redis error logging by removing unnecessary object wrapping.

Author: markmdev

apps/backend/src/app.ts

@@ -41,6 +41,7 @@ app.use(requestLogger);
 app.use(cookieParser());
 app.use(express.json());
 app.use(express.urlencoded({ extended: true }));
+app.set("trust proxy", 1);
 
 app.use("/api/vocab", vocabularyModule.router);
 app.use("/api/story", storyModule.router);
@@ -64,9 +65,12 @@ const startServer = async () => {
 
   const gracefulShutdown = async (signal: string) => {
     logger.info(`Received ${signal}. Stopping server...`);
-    prisma.$disconnect();
+    await prisma.$disconnect();
+    logger.info("Closed prisma connection");
     await closeRedisConnection();
+    logger.info("Closed Redis connection");
     await closeIORedisConnection();
+    logger.info("Closed IORedis connection");
     server.close((err) => {
       if (err) {
         logger.error("Error closing server:", err);
@@ -83,14 +87,14 @@ const startServer = async () => {
   };
 
   ["SIGINT", "SIGTERM"].forEach((sig) => {
-    process.on(sig, () => gracefulShutdown(sig));
+    process.once(sig, () => gracefulShutdown(sig));
   });
 
-  process.on("uncaughtException", (err) => {
+  process.once("uncaughtException", (err) => {
     logger.error("Uncaught exception:", err);
     gracefulShutdown("uncaughtException");
   });
-  process.on("unhandledRejection", (reason) => {
+  process.once("unhandledRejection", (reason) => {
     logger.error("Unhandled rejection:", reason);
     gracefulShutdown("unhandledRejection");
   });

apps/backend/src/services/redis/redisClient.ts

@@ -21,7 +21,7 @@ const connectRedis = async () => {
   try {
     await redisClient.connect();
   } catch (error) {
-    logger.error("Failed to connect to Redis", { error });
+    logger.error("Failed to connect to Redis", error);
     throw new RedisError("Failed to connect to Redis", error);
   }
 };
@@ -30,7 +30,7 @@ const closeRedisConnection = async () => {
   try {
     await redisClient.quit();
   } catch (error) {
-    logger.error("Failed to close redisClient", { error });
+    logger.error("Failed to close redisClient", error);
     throw new RedisError("Failed to close redisClient", error);
   }
 };

apps/backend/src/worker.ts

@@ -39,6 +39,6 @@ const shutdown = async () => {
   process.exit(0);
 };
 
-["SIGINT", "SIGTERM"].forEach((sig) => process.on(sig, shutdown));
+["SIGINT", "SIGTERM"].forEach((sig) => process.once(sig, shutdown));
 
 startWorker();

apps/backend/start-dev.sh

@@ -3,4 +3,4 @@ echo 'Waiting for DB to be ready...' &&
 npx prisma migrate deploy &&
 echo 'Migration complete, seeding data...' &&
 node ./prisma/seed-word-ranking.js
-npm run dev
+exec npm run dev

docker-compose-dev.yml

@@ -20,6 +20,7 @@ services:
     build:
       context: ./apps/lemmas
   backend:
+    init: true
     build:
       context: ./apps/backend
       dockerfile: Dockerfile.dev