I've been coding for a while now, mostly in Python and JavaScript. I've built web apps, scripts, and even dabbled in machine learning. But I was craving something a bit more low-level, something that would get my hands dirty with systems and networking. Go seemed like the perfect language for the job.

So, I decided to build a load balancer. It was a chance to learn how to manage traffic, handle multiple connections, and dive deep into Go's concurrency features. Let's break down how I did it.

Some Homework

Before I jumped into writing code, I had to do some studying. I needed to understand how computers talk to each other on the internet, like what language they use and how they find each other. I also looked into different ways to share work between computers, like who does what job.

Then, I set up my workspace. I got the right tools and made sure my computer was ready to go. It was like getting my workshop ready before building something cool.

Why a Load Balancer ?

Alright, let's get real. Why bother with a load balancer? Imagine your website is a super popular pizza shop. You're killing it, right? But then, suddenly, everyone in town wants your pizza. Your website, which is basically your online oven, starts to overheat. Orders pile up, customers get mad, and you end up with a pile of dough (figuratively speaking).

That's where a load balancer comes in. It's like hiring a super smart pizza delivery guy. This guy is always on the lookout for which oven (or server) is free. When an order (or request) comes in, he quickly directs it to the oven with the most capacity. This way, no oven (or server) gets overworked, and everyone gets their pizza (or website content) on time.

So, in short, a load balancer is like a traffic cop for your website. It makes sure everything runs smoothly, even when things get crazy.

But why build one? There are plenty of load balancers out there, right? Well, understanding how they work under the hood can be a game-changer. Plus, building your own is a great way to learn about networking, concurrency, and system design. It's like building your own car instead of just driving one. You get a deeper appreciation for the engineering involved.

Silence Before the Storm: Building the REST API

Before diving into the load balancer, I needed some services to distribute traffic to. I created a simple REST API with basic endpoints for health checks and dummy workloads. This served as a testbed for the load balancer.

Building the API itself was fairly straightforward using Go's net/http package. I defined endpoints for health checks and basic operations. The health check endpoint returned a simple status indicating the server's health, while the other endpoints performed some dummy computations to simulate workload.

However, ensuring the reliability of these backend services was crucial. I implemented basic health checks to monitor their status. This involved periodically sending requests to the health check endpoint and marking servers as unhealthy if they failed to respond within a certain timeframe.

For Heaven's Sake: Building the Load Balancer

The next step was to build the actual load balancer. This involved several key components. First, I needed a way to keep track of all the available servers. I created a registry to store information about each server, including its address and health status. For this project, I used a simple in-memory structure, but in a production environment, a distributed system like etcd would be more suitable.

The core of the load balancer is the algorithm used to distribute traffic. I started with a basic round-robin approach, but more complex strategies like least connections or weighted round robin can be implemented based on specific requirements.

To handle incoming connections, I used Go's net package to create a listener socket. Each incoming connection was handled by a separate goroutine, allowing for concurrent processing. This was crucial for handling a high volume of traffic efficiently.

Ensuring the availability of backend servers was a top priority. I implemented basic health checks to monitor server status. If a server was found to be unhealthy, it was removed from the load balancer's rotation. However, for production environments, more sophisticated health checks like active probes or load-based checks are often required.

Building a robust load balancer is a complex task that involves careful consideration of factors like performance, scalability, and fault tolerance. While this project provided a solid foundation, production-grade load balancers typically require additional features and optimizations.

So, What's next ?

Building this load balancer was like putting together a puzzle. There were definitely times I wanted to throw in the towel, but the satisfaction of seeing it all come together was worth it.

I learned a ton about Go's concurrency features, which were essential for handling multiple connections and background tasks. Understanding how to manage resources efficiently was also a key takeaway. Plus, I got a solid grasp of networking concepts and how to build a resilient system.

While this load balancer is a good starting point, there's still a long way to go. I'd love to explore more advanced load balancing algorithms, implement features like sticky sessions, and integrate with service discovery systems.

If you're interested in diving deeper into load balancing or Go, I encourage you to give it a shot. It's a challenging but rewarding journey. Feel free to share your experiences or ask any questions in the comments below.