basic-order-processing-worker

Basic Order Processing - Worker

Consumer application demonstrating type-safe AMQP message consumption with multiple handlers.

📖 Full documentation →

Quick Start

# Start RabbitMQ
docker run -d --name rabbitmq -p 5672:5672 rabbitmq:4-management

# Run the worker
pnpm --filter @amqp-contract-examples/basic-order-processing-worker dev

Code Organization

This sample demonstrates two approaches to organizing worker handlers:

Inline Handlers (src/index.ts - Main Example)

Handlers are defined directly in the worker creation. This approach is suitable for:

• Simple applications with few handlers
• Quick prototypes
• When handlers don't need to be reused

const worker = (
  await TypedAmqpWorker.create({
    contract: orderContract,
    handlers: {
      processOrder: ({ payload }) => {
        // Handler logic here
        return okAsync(undefined);
      },
      notifyOrder: ({ payload }) => {
        // Handler logic here
        return okAsync(undefined);
      },
    },
    urls: [env.AMQP_URL],
  })
)._unsafeUnwrap();

External Handlers (src/handlers.ts)

Handlers can be organized in separate files using defineHandler or defineHandlers. The src/handlers.ts file demonstrates this pattern, which is recommended for:

• Production applications
• Better code organization and testability
• Reusable handlers across multiple workers
• Clearer separation of concerns

// handlers.ts
export const processOrderHandler = defineHandler(orderContract, "processOrder", ({ payload }) => {
  // Handler logic here
  return okAsync(undefined);
});

// index.ts - to use external handlers, import them:
import { processOrderHandler /* other handlers */ } from "./handlers.js";

const worker = (
  await TypedAmqpWorker.create({
    contract: orderContract,
    handlers: {
      processOrder: processOrderHandler,
      // ... other handlers
    },
    urls: [env.AMQP_URL],
  })
)._unsafeUnwrap();

The main src/index.ts file uses inline handlers for simplicity, while src/handlers.ts provides an example of how to organize handlers externally for better maintainability.

Environment Variables

Variable	Default	Description
AMQP_URL	amqp://localhost:5672	RabbitMQ connection URL
LOG_LEVEL	info	Log level (info, debug, etc.)

For detailed documentation, visit the website.