Jump to content

Rust in Production: Why Reliability Is Worth the Learning Curve

From JOHNWICK

1. The Moment I Knew I Needed Rust When you’ve spent enough nights debugging memory leaks in C++ or chasing race conditions in Go, you start to crave safety.
Not theoretical safety — actual guarantees that your code won’t collapse under pressure at 2 a.m. That’s how I discovered Rust.

I wasn’t trying to chase trends or impress recruiters. I was trying to fix a system that crashed every few days for reasons that felt… supernatural. Logs were clean. Stack traces looked fine. Yet, somehow, we’d hit segmentation faults. So I did what every desperate engineer does: I rebuilt a small piece of it in Rust — just to see if it would behave better. It did. And it never broke again.


2. The Early Frustration

My first week with Rust was humbling.
The compiler yelled at me constantly. Ownership rules felt alien. Borrowing and lifetimes made me question my programming ability. Coming from Python, I was used to freedom — not fences. But Rust doesn’t care about your habits. It forces you to write safe code, even when you’d prefer a shortcut.

For example, here’s something that looks innocent enough:

fn main() {

   let mut name = String::from("Rust");
   let ref1 = &name;
   let ref2 = &mut name; // ❌ Compiler error: cannot borrow `name` as mutable because it is also borrowed as immutable
   println!("{}", ref1);

}

That single line could cause undefined behavior in C or C++, but Rust stops you before it even runs. At first, that was frustrating.
But slowly, I started realizing that every compiler error was preventing a potential production bug.


3. Why the Borrow Checker Became My Friend

The moment it clicked for me was when I rewrote a data ingestion service that handled thousands of concurrent requests.
In Go, I’d occasionally hit data races — not because Go was unsafe, but because I was careless.

In Rust, the borrow checker refused to let me even compile race-prone code.
That constraint made me rethink how I structured memory, ownership, and concurrency.

Here’s a simplified example of what Rust helped me avoid:

use std::thread;

fn main() {

   let mut counter = 0;
   let handles: Vec<_> = (0..5)
       .map(|_| {
           thread::spawn(|| {
               // ❌ Can't mutate `counter` safely across threads
               // Compiler forces you to use synchronization primitives
           })
       })
       .collect();
   for handle in handles {
       handle.join().unwrap();
   }

}

The compiler’s refusal wasn’t punishment — it was protection.
It forced me to use channels or mutexes to share data correctly. Once I embraced that, concurrency bugs disappeared.


4. Performance Without Panic

When we finally shipped Rust into production, it replaced one of our most performance-critical services — a data pipeline stage that validated and serialized large JSON files.

The results were ridiculous.

  • Latency dropped by over 60%.
  • CPU utilization fell by half.
  • Memory leaks? Gone.
  • Restarts? Zero.

And here’s the crazy part — it wasn’t even heavily optimized Rust. Just clean, idiomatic, safe code.

Example of a JSON transformation snippet:

use serde::{Deserialize, Serialize};

  1. [derive(Serialize, Deserialize, Debug)]

struct Record {

   id: u32,
   name: String,

}

fn main() -> Result<(), Box<dyn std::error::Error>> {

   let json_data = r#"[{"id":1,"name":"Alice"},{"id":2,"name":"Bob"}]"#;
   let records: Vec<Record> = serde_json::from_str(json_data)?;
   for record in &records {
       println!("User: {} ({})", record.name, record.id);
   }
   let output = serde_json::to_string_pretty(&records)?;
   println!("{}", output);
   Ok(())

}

This single function handled tens of thousands of records per second, flawlessly.
And unlike my older Node.js version, it didn’t choke under high load.


5. Rust in a Team Setting

Adopting Rust wasn’t just a technical change — it was cultural. Our senior devs were skeptical at first. “Why rewrite what works?” was the question that echoed in every meeting.
But once they saw the reduction in runtime bugs and the measurable stability, things shifted.

Rust’s strictness forced us to improve code reviews.
Every PR turned into a discussion about ownership and design rather than syntax or style.

We started documenting lifetimes, designing structs around clear ownership, and thinking in systems, not snippets.
Rust didn’t just change our code — it improved how we thought.


6. Integrating Rust into Existing Systems

If you’re thinking, “I can’t rewrite everything in Rust,” you’re right. You shouldn’t. We didn’t either. 
Instead, we used Rust for performance-critical components — the “hot path” of our architecture. The rest stayed in Python or Node. One of the easiest ways to blend Rust into an existing ecosystem is through FFI (Foreign Function Interface) or WebAssembly.

For example, here’s how we integrated Rust into Python:

// src/lib.rs use pyo3::prelude::*;

  1. [pyfunction]

fn multiply(a: i32, b: i32) -> PyResult<i32> {

   Ok(a * b)

}

  1. [pymodule]

fn fastmath(_py: Python, m: &PyModule) -> PyResult<()> {

   m.add_function(wrap_pyfunction!(multiply, m)?)?;
   Ok(())

}

Then in Python:

import fastmath

print(fastmath.multiply(6, 7)) # 42

This tiny bridge allowed us to run Rust’s speed where it mattered most — while keeping the simplicity of Python everywhere else.


7. Security Without Sacrifice

Rust’s design eliminates entire classes of vulnerabilities — no null pointers, no data races, no buffer overflows. 
For a company that handled sensitive data, that was a game changer. We didn’t need external memory sanitisers or complex runtime checks — the compiler did the heavy lifting. 
And because there’s no garbage collector, performance was predictable and consistent.

I remember watching our monitoring dashboard after deploying a Rust service — zero spikes, zero crashes, zero memory drift.
That moment sold me on Rust for good.


8. The Payoff

Yes, Rust’s learning curve is real.
You’ll struggle, curse the borrow checker, and rewrite functions five times before it compiles.
But once it does — it runs perfectly. That trade-off — slow learning for fast, stable runtime — is what makes Rust so powerful. 
Every line you write buys you long-term confidence. Our team now uses Rust for microservices that need speed, uptime, and safety.
And honestly, I sleep better knowing a single pointer can’t silently take down a production system.


Final Thoughts

Rust isn’t for everything.
If you’re building prototypes or quick scripts, it might feel like overkill.
But when you’re shipping code that handles real money, critical data, or millions of requests — reliability is the real feature. Learning Rust taught me that performance isn’t about faster code — it’s about predictable behaviour under pressure. And once you experience that kind of reliability, going back feels impossible.

Read the full article here: https://medium.com/rustaceans/rust-in-production-why-reliability-is-worth-the-learning-curve-7f51f41a46e3