Have you ever been part of an On-Call rotation?

If so, you know how annoying it is to have monitoring alerts that you can’t trust. If they don’t trigger, you’ll live in fear of missing an incident. If they trigger too much, they won’t let you sleep. Neither case sounds great.

On-Call me maybe

Over the past year and a half, I’ve been part of projects that practice On-Call. You’d be surprised how easily people get used to situations that are so clearly dysfunctional. In this post, I want to talk about how I’ve tried to improve the quality of our alerts.

What Is the Goal of Alerting?

Simply…


In my previous post, Starting a New App With Redux? Consider Context API First, I wrote about the Context API as a viable alternative to Redux. In this post, I want to show how a React application using Redux looks when using the Context API.

First Considerations

I’m assuming that my previous article intrigued you enough that you’re considering migrating away from Redux. You have to ask yourself: Is a migration worth it? The approach based on the Context API might be simpler, but that’s not enough of an argument on its own to rewrite perfectly functional code.

I can’t tell you…


Agile development has a complex relationship with management. Some old school organizations want to call themselves agile, without changing anything substantive. So they maintain the same hierarchies as before and keep decisions out of the team. But they use story points. Others react to this and go the opposite way: They have teams where every single thing is supposed to be decided in a “democratic” way. It tends to lead to a lot of meetings and few if any actual decisions.

So, there seems to be still plenty of space for books like this one. This book intends to give…


Tell me about your biggest flaw

Technical interviews are a contentious topic, to say the least. It applies both as a candidate and as an interviewer. It feels that you end up sinking a lot of time into it, often with little to show for it.

More concretely, it seems that take-home coding assignments are becoming more and more the norm in the tech industry. Do you have opinions about them? I surely do! In this post, I want to talk about some practices I’ve observed lately that make companies look bad and poison the goodwill essential for a successful interaction between candidates and companies.

What is a Take-home Coding Assignment, anyways?

It’s…


I’ve been working with OAuth a lot lately. Just recently, I wrote about setting it up for grafana. Today, I want to talk about the recommended flow for Single Page Applications, Authorization Code Flow with PKCE. I’m going to add authorization to a React application leveraging Auth0 as an Identity Provider.

I mention Auth0 so often around here, you’d think I’m getting a referral bonus. I promise you I’m not! It’s deserved praise. The UI is easy to navigate, is conveniently provisioned with Terraform, and has powerful libraries for most programming languages. I wrote about verifying JWTs from a SpringBoot…


We’ll need your signature, mister

I’ve gotten into the habit at work of signing my commits in git with my GPG key. It adds an extra layer of integrity to the source code, as it enables us to know who produced each commit (if the practice is followed widely).

It requires some initial configuration, but after that, it adds very little overhead.

Even if your organization doesn’t have a policy requiring it, I think it’s still worth setting up. Let’s see how to do it.

Even if it’s not required by your organization’s policies, I think it’s still worth setting up. …


This seminal book aims to answer one simple yet fundamental question: What makes an organization that develops software successful? This is a topic that has been explored in depth by many, many authors. The key difference is the comprehensive body of research that the authors have compiled. Like, they’re using actual science for this, man.

As could be expected, it is a mixture of product development, practices, organizational alignment, and technical practices. The book is not exploring the topics comprehensively, but it’s definitely a good start.

It comes down to Continuous delivery, in the end. Who would’ve thought? Rapid iteration…


Be careful of the debris

The appeal behind using Kubernetes is that you abstract the details of where your applications run and leave it in k8s’s hands. It’ll schedule containers following some given constraints, and restart them if they crash.

However, a Kubernetes cluster is not a perfect abstraction. That is especially visible as an operator. Even if you use a managed solution like AWS EKS, you still have to perform some maintenance yourself.

As an operator, I want this maintenance to happen regularly, to avoid stagnation and prevent failure. As a developer, I avoid unwanted interruptions for my applications. A Pod Disruption Budget (PDB)…


Team topologies is a book about software delivery that doesn’t mention technology. Rather, it’s about how to organize teams.

It’s almost impossible to work in the software industry and not hear regularly about Conway’s law (It’s not actually a law). It turns out that the way an organization is set up will influence the software architecture that it produces. Everybody is mindlessly using microservices regardless of fit. But if I’m allowed to quote myself:

All the fancy technology in the world won’t fix an organizational problem.

That’s pretty much the point of this book. Fast flow is easier to achieve…


The ingress police is watching

It seems hard to believe, but I had never written about Kubernetes before. It feels impossible to hold a conversation about technology for more than five minutes without coming to the topic of k8s. Let’s fix that. I have to publish a couple of articles centered around Kubernetes to catch up.

If you operate a Kubernetes cluster with any significant usage, chances are you’re using an Ingress Controller. It just seems the thing to do. I’ve had a thing for Traefik for a while. However, the path of least resistance is to use the NGINX Ingress Controller. …

Mario Fernández

I develop software for a living. Then I go home and I continue reading about software, because I just cannot get enough. Nowadays I work for ThoughtWorks.

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