#  Weather Web App - Kubernetes Deployment

This project deploys a full-stack weather web application to Kubernetes. It includes:
- A frontend website to search weather by city
- A backend PostgreSQL database for logging searches
- A Node.js API to connect the frontend to the database

---

##  Application Description

- **Frontend (weather.html):** A responsive, modern web UI that shows current weather data using the OpenWeatherMap API.
- **Backend (PostgreSQL):** Stores weather search history via a `weather_log` table.
- **API Server (Node.js):** Receives weather data from the frontend and logs it to the PostgreSQL database.

---

##  Containers Used

| Container         | Image              | Description                                  |
|------------------|--------------------|----------------------------------------------|
| `weather-frontend` | Custom Nginx-based | Serves the `weather.html` UI                 |
| `postgres`        | `postgres:15`      | Provides relational database backend         |
| `weather-api`     | Custom Node.js     | API that logs weather data to PostgreSQL     |

---

## ☸️ Kubernetes Objects

| Object Type            | File                 | Description                                                          |
|------------------------|----------------------|----------------------------------------------------------------------|
| `Namespace`            | (inside script)       | Isolates resources under `webapp-ns`                                 |
| `Deployment`           | `deployment.yaml`     | Manages frontend app                                                 |
| `Deployment`           | `deployment-api.yaml` | Manages the Node.js API                                              |
| `StatefulSet`          | `statefulset.yaml`    | Manages PostgreSQL instance with persistent volume                   |
| `PersistentVolume`     | `statefulset.yaml`    | Host-mounted volume for PostgreSQL data                              |
| `PersistentVolumeClaim`| `statefulset.yaml`    | Requests storage for StatefulSet                                     |
| `Service`              | `service.yaml`        | Exposes frontend via NodePort                                        |
| `Service`              | `deployment-api.yaml` | Exposes API via NodePort                                             |
| `ConfigMap`            | Created by script     | Stores `init-db.sql` used to create the `weather_log` table          |

---

##  Networking & Volumes

### Virtual Networks:
- Kubernetes handles inter-service communication via internal DNS and `ClusterIP` services.
- Frontend and backend are externally reachable using `NodePort` services.

### Volumes:
- `PersistentVolume` and `PersistentVolumeClaim` ensure PostgreSQL data is retained.
- `ConfigMap` mounts the SQL init script for PostgreSQL setup.

---

## ⚙️ Container Configurations

### Frontend
- Dockerfile uses `nginx:alpine`
- Serves `weather.html` (renamed as `index.html` inside container)
- Exposed on port `80`

### Node.js API
- Built with Node.js 18
- Listens on port `3000`
- Connects to PostgreSQL using service DNS
- Accepts POST requests at `/log` with weather data

### PostgreSQL
- `postgres:15` with `weatheruser`, `weatherpass`, and `weatherdb`
- Init script creates a `weather_log` table with a sample row

---

##  How to Use the Application

### 1. Build Docker Images

```bash
./prepare-app.sh
```

### 2. Start the App (create namespace and apply all configs)

```bash
./start-app.sh
```

### 3. View the App

```bash
minikube service weather-service -n webapp-ns
```

Or get the NodePort manually:

```bash
kubectl get svc -n webapp-ns
minikube ip
```

Then open:
```
http://<minikube-ip>:<frontend-nodeport>
```

### 4. Use the App
- Enter a city
- Weather will be shown
- Data is logged in PostgreSQL automatically

### 5. Stop and Clean Up

```bash
./stop-app.sh
```

---

##  API Key Setup

- Register at [OpenWeatherMap](https://openweathermap.org/api)
- Get your free API key
- Replace the placeholder in `weather.html`:

```js
const apiKey = "YOUR_API_KEY";
```

---

##  Conclusion

- Frontend calls OpenWeatherMap and logs data to your backend
- PostgreSQL is prepped with a table to store queries
- You can expand the API to serve saved data or stats