fix: update javascript-node-postgres network config and postgres volume mount

Replace network_mode: service:db with bridge network (app-network) to fix
DNS resolution failures in CI. Update postgres volume mount from
/var/lib/postgresql/data to /var/lib/postgresql for PostgreSQL 18+
compatibility. Update NOTES.md to reflect hostname db instead of localhost.

Co-authored-by: Kaniska244 <[email protected]>

Author: Copilot

src/javascript-node-postgres/.devcontainer/docker-compose.yml

@@ -1,4 +1,5 @@
-version: '3.8'
+volumes:
+  postgres-data:
 
 services:
   app:
@@ -12,17 +13,30 @@ services:
     # Overrides default command so things don't shut down after the process ends.
     command: sleep infinity
 
-    # Runs app on the same network as the database container, allows "forwardPorts" in devcontainer.json function.
-    network_mode: service:db
+    # Use proper Docker networking instead of network_mode: service:db
+    # to ensure reliable DNS resolution in all environments
+    depends_on:
+      db:
+        condition: service_healthy
+    networks:
+      - app-network
 
     # Use "forwardPorts" in **devcontainer.json** to forward an app port locally. 
     # (Adding the "ports" property to this file will not forward from a Codespace.)
 
   db:
     image: postgres:latest
     restart: unless-stopped
+    networks:
+      - app-network
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 30s
     volumes:
-      - postgres-data:/var/lib/postgresql/data
+      - postgres-data:/var/lib/postgresql
     environment:
       POSTGRES_PASSWORD: postgres
       POSTGRES_USER: postgres
@@ -31,5 +45,6 @@ services:
     # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
     # (Adding the "ports" property to this file will not forward from a Codespace.)
 
-volumes:
-  postgres-data:
+networks:
+  app-network:
+    driver: bridge

src/javascript-node-postgres/NOTES.md

@@ -5,7 +5,7 @@ This template references an image that was [pre-built](https://containers.dev/im
 
 ## Using this template
 
-This definition creates two containers, one for Node.js and one for PostgreSQL. You will be connected to the Node.js container, and from within that container the PostgreSQL container will be available on **`localhost`** port 5432. The default database is named `postgres` with a user of `postgres` whose password is `postgres`, and if desired this may be changed in `docker-compose.yml`. Data is stored in a volume named `postgres-data`.
+This definition creates two containers, one for Node.js and one for PostgreSQL. You will be connected to the Node.js container, and from within that container the PostgreSQL container will be available on **`db`** port 5432. The default database is named `postgres` with a user of `postgres` whose password is `postgres`, and if desired this may be changed in `docker-compose.yml`. Data is stored in a volume named `postgres-data`.
 
 While the definition itself works unmodified, it uses the `mcr.microsoft.com/devcontainers/javascript-node` image which includes `git`, `eslint`, `zsh`, [Oh My Zsh!](https://ohmyz.sh/), a non-root `vscode` user with `sudo` access, and a set of common dependencies for development.