Go Caching Proxy Server

Overview

This project is a high-performance Caching Proxy Server built in Go. It acts as an intermediary between clients and an origin server, caching responses in Redis to dramatically improve response times and reduce the load on the origin.

This refactored version includes:

• Content-Agnostic Caching: Caches any type of content, not just JSON.
• Configuration via Environment Variables: Easy to configure and deploy.
• Graceful Shutdown: Ensures no in-flight requests are dropped on shutdown.
• Modular Codebase: A clean, maintainable, and testable structure.
• Unit Tests: Robust tests to ensure reliability.

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Prerequisites

• Go (v1.18+)
• Make
• Docker & Docker Compose

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🚀 Getting Started

1. Start Redis

To run the proxy, you first need a Redis instance. A docker-compose.yml file is provided for convenience.

make start-redis

This will start a Redis container in the background and expose it on port 6379.

2. Run the Application

Once Redis is running, you can build and start the proxy server with a single command:

make run

By default, the server will start on port 8080 and proxy requests to https://dummyjson.com.

3. Test the Proxy

You can now send requests to the proxy. The X-Cache header in the response will tell you if you got a HIT or a MISS.

# First request (MISS)
curl -v http://localhost:8080/products/1

# Second request (HIT)
curl -v http://localhost:8080/products/1

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⚙️ Configuration

The application is configured using environment variables. You can override the default values by setting them in your shell or including them in the make run command.

Variable	Description	Default Value
PORT	Port for the proxy server to listen on.	8080
ORIGIN_URL	The target origin server to proxy requests to.	https://dummyjson.com
REDIS_ADDR	The address of the Redis server.	localhost:6379
CACHE_EXPIRES	Cache expiration time (e.g., 5m, 1h).	10m

Example with Custom Configuration:

export PORT=4000
export ORIGIN_URL=http://my-api.com
make run

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✨ Available make Commands

• make build: Compiles the Go binary.
• make run: Builds and runs the server.
• make test: Runs all unit tests.
• make tidy: Tidies up Go module dependencies.
• make clean: Removes the compiled binary and test cache.
• make start-redis: Starts the Redis container.
• make stop-redis: Stops the Redis container.
• make check-redis: Pings the Redis container to check connectivity.

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Project Structure

.
├── cmd/
│   └── main.go              # Application entry point with graceful shutdown
├── internal/
│   ├── proxy.go             # Core proxy and caching logic
│   ├── proxy_test.go        # Unit tests for the proxy
│   ├── redis.go             # Redis client initialization
│   └── server.go            # Server setup and lifecycle management
├── pkg/
│   └── config/
│       └── config.go        # Configuration loader from environment variables
├── Makefile                 # Automation for build, run, test, etc.
├── go.mod                   # Go module dependencies
├── go.sum
└── docker-compose.yml       # Docker Compose for Redis service

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License

This project is licensed under the MIT License.