Go Server Examples

This project contains both gRPC and HTTP REST API server examples built with Go. It includes basic CRUD operations for user management.

Project Structure

├── go.mod                    # Go module definition
├── proto/                    # Protocol Buffer definitions (gRPC)
│   ├── user.proto           # Proto definitions
│   ├── user.pb.go           # Generated Go structs
│   └── user_grpc.pb.go      # Generated gRPC code
├── server/                   # gRPC Server
│   └── main.go              # gRPC Server implementation
├── client/                   # gRPC Client
│   └── main.go              # gRPC Test Client
├── simple-server/            # HTTP REST API Server
│   └── main.go              # HTTP Server implementation
├── simple-client/            # HTTP REST API Client
│   └── main.go              # HTTP Test Client
├── test-commands.sh          # Automated test script
└── README.md

Requirements

• Go 1.21+
• Protocol Buffers compiler (protoc) - optional for gRPC

Installation

# Download dependencies
go mod tidy

Running the HTTP REST API Server (Recommended)

1. Start the HTTP Server

go run simple-server/main.go

The server will start on port 8080 with these endpoints:

• POST /users - Create user
• GET /users/{id} - Get user by ID
• GET /users - List all users

2. Test the HTTP Client

In another terminal:

go run simple-client/main.go

How to View and Test the Server

1. Web Browser

Once the server is running, open your browser and visit:

• List all users: http://localhost:8080/users
• Get specific user: http://localhost:8080/users/1

2. Command Line with curl

Manual Testing:

# Create a user
curl -X POST http://localhost:8080/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Alice Johnson","email":"alice@example.com"}'

# Get a user by ID
curl http://localhost:8080/users/1

# List all users
curl http://localhost:8080/users

# Test non-existent user (should return error)
curl http://localhost:8080/users/999

Automated Testing:

Run the included test script:

chmod +x test-commands.sh
./test-commands.sh

3. Go Client

go run simple-client/main.go

Expected Responses:

Create User:

{"id":1,"message":"User successfully created: Alice Johnson"}

Get User:

{"id":1,"name":"Alice Johnson","email":"alice@example.com"}

List Users:

[{"id":1,"name":"Alice Johnson","email":"alice@example.com"}]

Non-existent User:

User not found: 999

Running the gRPC Server (Advanced)

1. Start the gRPC Server

go run server/main.go

The server will start on port 50051.

2. Test the gRPC Client

In another terminal:

go run client/main.go

Features

• GetUser: Retrieve user by ID
• CreateUser: Create new user
• ListUsers: List all users (HTTP only)
• Thread-safe in-memory storage
• Simple error handling
• Context timeout support (gRPC)

Sample Output (HTTP)

=== Creating New Users ===
Result: User successfully created: John Doe (ID: 1)
Result: User successfully created: Jane Smith (ID: 2)

=== Retrieving Users ===
User 1: John Doe (john@example.com)
User 2: Jane Smith (jane@example.com)

=== Listing All Users ===
User 1: John Doe (john@example.com)
User 2: Jane Smith (jane@example.com)

=== Non-existent User Test ===
Expected error: user not found: User not found: 999

Performance Comparison

HTTP REST API:

• Simple JSON over HTTP/1.1
• Easy to debug and test
• Wide compatibility
• Human-readable

gRPC:

• Binary protocol over HTTP/2
• Type-safe with Protocol Buffers
• Better performance for high-throughput
• Streaming support
• Multi-language client generation

Advanced Features

You can extend these examples with:

• Database integration (PostgreSQL, MongoDB)
• Authentication/Authorization (JWT)
• Middleware (logging, metrics, tracing)
• Docker containerization
• Kubernetes deployment
• API documentation (OpenAPI/Swagger for REST)