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Sifter: Scalable Sampling for Distributed Tracing

Distributed tracing can be ridiculously expensive if you try to trace a hundred percent of requests. A common technique to reduce costs is to sample only a small portion of the traffic. But naive sampling techniques like uniform sampling will inevitably capture more common-case executions and might miss the more interesting edge cases. Instead, Sifter’s approach is to bias sampling decisions towards outliers and anomalous traces. This way, anomalous traces have a higher chance of being sampled, and the more uninteresting traces are discarded.

written in distributed-tracing, observability, papers, sampling Read on →

Google Docs Could Be So Much Better!

Lots of businesses run on Google Docs. It’s how we write memos, define strategies, discuss proposals, document decisions, write tutorials, and plenty of other things.

Google Docs is a fantastic piece of technology. I almost can’t imagine how we worked before it (productStrategy-Jun-2004-version13.docx anyone?). And yet, I sometimes feel like it could be so much more! Like we’ll look back in 10 years and think: “My god! I can’t believe we were working that way!”. Improving Docs has the potential of completely overhauling the way information flows through an organization. Here are some ideas on how Google could improve it.

written in Read on →

About Deploying on Fridays

Common knowledge says that you don’t deploy on Friday if you want to have a peaceful weekend. Yet, some people will tell you that if you’re not comfortable deploying every day of the week, you’re doing it wrong. They’ll say that deploying shouldn’t be scary and that you probably don’t have enough tests. So, which one is it?

written in ci/cd, deploy, deployment, o11y, observability, release Read on →

Documenting Decisions

It’s Monday morning. You’re sitting at your desk with your steaming cup of Joe, ready to sink your teeth into that new feature you have to develop. The git pull downloads months worth of changes, and you dive into the code. Piece by piece, you start building a mental model of the system, trying to make sense of the different components. But something doesn’t feel right. Why was it built this way? It feels weird, it feels so obviously wrong, so poorly designed, so suboptimal.

You realize you need help. Whoever wrote this mess should be able to provide some context. You run git blame and your own name hits you in the face like a brick. You start thinking that maybe it’s no so wrong. That you probably had your reasons. If you could only go back in time and ask your past self…

written in architecture, culture, documentation Read on →

Effective Testing - Reducing Non-determinism to Avoid Flaky Tests

Flaky tests are those that randomly fail for no apparent reason. If you have a flaky test, you might re-run it, over and over, until it succeeds. If you have a couple of them, the chances of all passing at the same time are slim, so maybe you ignore the failures. You know, just this one time… Soon enough, you’re not paying attention to failures on this test suite. Congratulations! Your tests are now worthless.

written in effective-testing-series, flaky, non-determinism, testing, tests Read on →

Graphic Design Tools for Backend Engineers

You might think that being a backend engineer means you’ll never have to draw anything more complex than a bunch of boxes connected with arrows (or hexagons if are going all cloud native). This is simply not true, and that’s why you’re here.

At some point you’ll find yourself producing system diagrams, flow-charts, slides, mockups, maybe even icons! So, let me show you some tools and tricks I picked up over the years to fake it at design.

written in communication, design, draw, graphic, graphs, productivity, soft-skill, tools, visual Read on →

Using PowerMock + TestNG to Mock a Static Class

 This week I needed to test a class that depended on a method from an static class. I saw we were using PowerMock and thought to myself: “Well this sounds pretty common, I bet it’s easy to accomplish”. But of course I ran into half a dozen issues before I was able to make it work. Here’s my two cents to make your experience easier than mine.

written in java, mocking, testing Read on →

Android Animations Are Just a Trick

So I was learning to animate Views in Android using this video and was having trouble with the second time the animation runned. First run the objects end up in their destination, second run it was mayhem. I had fallen victim to the great misunderstanding everyone makes about Android animations: they are just a magic trick.

written in android Read on →

Value Types the Easy Way

Value types is a fancy name for those classes where you have to implement equals() and hashCode(), and usually toString(). You’ve probably wrote thounsands of those classes, but have you ever wonder why do you have write almost 50 lines of code to express such a common concept?

written in java, libs Read on →

Why Was This Blog Created

There are billions of blogs written by more experienced and talented devs, there is stackoverflow.com and communities for each tool and language ever created, so why bother creating yet another dev blog? Here are the two reasons why I started this blog.

written in offtopic Read on →