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# Hello World Example

This is the simplest Dynamo example demonstrating a basic service using Dynamo's distributed runtime. It showcases the fundamental concepts of creating endpoints and workers in the Dynamo runtime system.

## Architecture

```text
Client (dynamo_worker)
      │
      ▼
┌─────────────┐
│   Backend   │  Dynamo endpoint (/generate)
└─────────────┘
```

## Components

- **Backend**: A Dynamo service with an endpoint that receives text input and streams back greetings for each comma-separated word
- **Client**: A Dynamo worker that connects to and sends requests to the backend service, then prints out the response

## Implementation Details

The example demonstrates:

- **Endpoint Definition**: Using the `@dynamo_endpoint` decorator to create streaming endpoints
- **Worker Setup**: Using the `@dynamo_worker()` decorator to create distributed runtime workers
- **Service Creation**: Creating services and endpoints using the distributed runtime API
- **Streaming Responses**: Yielding data for real-time streaming
- **Client Integration**: Connecting to services and processing streams
- **Logging**: Basic logging configuration with `configure_dynamo_logging`

## Getting Started

## Prerequisites

 Before running this example, ensure you have the following services running:

 - **etcd**: A distributed key-value store used for service discovery and metadata storage
 - **NATS**: A high-performance message broker for inter-component communication

 You can start these services using Docker Compose:

 ```bash
 # clone the dynamo repository if necessary
 # git clone https://github.com/ai-dynamo/dynamo.git
 cd dynamo
 docker compose -f deploy/docker-compose.yml up -d
 ```

### Running the Example

First, start the backend service:
```bash
cd examples/runtime/hello_world
python hello_world.py
```

Second, in a separate terminal, run the client:
```bash
cd examples/runtime/hello_world
python client.py
```

The client will connect to the backend service and print the streaming results.

### Expected Output

When running the client, you should see streaming output like:
```text
Hello world!
Hello sun!
Hello moon!
Hello star!
```

## Code Structure

### Backend Service (`hello_world.py`)

- **`content_generator`**: A dynamo endpoint that processes text input and yields greetings
- **`worker`**: A dynamo worker that sets up the service, creates the endpoint, and serves it

### Client (`client.py`)

- **`worker`**: A dynamo worker that connects to the backend service and processes the streaming response

## Deployment to Kubernetes

Follow the [Quickstart Guide](../../../docs/guides/dynamo_deploy/quickstart.md) to install Dynamo Cloud.
Then deploy to kubernetes using

```bash
export NAMESPACE=<your-namespace>
cd dynamo
kubectl apply -f examples/runtime/hello_world/deploy/hello_world.yaml -n ${NAMESPACE}
```

to delete your deployment:

```bash
kubectl delete dynamographdeployment hello-world -n ${NAMESPACE}
```