02-microservices

Microservices Development Example

This example demonstrates devloop managing a microservices architecture with multiple Go services, shared libraries, and an API gateway.

What's Included

• API Gateway: Routes requests to appropriate microservices (port 20201)
• Auth Service: Handles authentication and JWT tokens (port 20202)
• User Service: Manages user data and profiles (port 20203)
• Shared Libraries: Common utilities and types used across services

Prerequisites

• Go 1.20 or higher
• devloop installed (go install github.com/panyam/devloop@latest)

Quick Start

1. Install dependencies:

   make deps

2. Run with devloop:

   make run
   # Or directly: devloop -c .devloop.yaml

3. Test the services:

   # Health check
   curl http://localhost:20201/health
   
   # Get auth token
   curl -X POST http://localhost:20201/auth/login \
     -H "Content-Type: application/json" \
     -d '{"username":"demo","password":"demo123"}'
   
   # Get user info (requires token from above)
   curl http://localhost:20201/users/123 \
     -H "Authorization: Bearer <token>"

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   Client    │────▶│ API Gateway │────▶│Auth Service │
│             │     │    :20201   │     │    :20202   │
└─────────────┘     └──────┬──────┘     └─────────────┘
                           │
                           ▼
                    ┌─────────────┐     ┌─────────────┐
                    │User Service │     │   Shared    │
                    │    :20203    │────▶│  Libraries  │
                    └─────────────┘     └─────────────┘

Service Communication

• API Gateway routes /auth/* to Auth Service
• API Gateway routes /users/* to User Service
• Services communicate via HTTP/REST
• Shared libraries provide common types and utilities

Try It Out

1. Modify shared libraries (shared/types.go):

   • Add a new field to the User struct
   • Watch all services rebuild automatically

2. Update the auth service (auth-service/main.go):

   • Change the JWT expiration time
   • Only the auth service restarts

3. Add a new endpoint to any service:

   • The specific service rebuilds
   • Other services remain running

Development Tips

• Each service has its own log prefix for easy identification
• Services are started in dependency order (shared → services → gateway)
• Use run_on_init: true ensures all services start immediately
• Process groups ensure clean shutdown of all related processes

Troubleshooting

• Port conflicts: Ensure ports 20201-20203 are available
• Service discovery: Services use hardcoded ports for simplicity
• Compilation errors: Check shared library changes don't break services