A brief intro to the Armeria Hyperfocal blog series, spotlighting Armeria features with practical code examples.

In my last post, Monitoring Prometheus metrics from Armeria, we took a look at how you can monitor Armeria metrics using Grafana. In this post, I would like to show you how you can customize Armeria metrics to suit your needs.

In this post, we'll be taking a look at how you can monitor Prometheus metrics collected with Armeria. For those of you who are trying Armeria for the first time, I will be adding simple practice samples so that you can follow along.

What is a circuit breaker?​

Suppose an unexpected failure occurs (For example, a network issue or a server crash) and a remote server is unable to respond to the request. If so, the client who made the request to the remote server will either wait for a response until a timeout occurs, consume resources, or eventually continue to send unnecessary requests. And on a Microservice Architecture (MSA), this client can also be a server for other services. In the end, clients of this server will have the same problem.

In the first part of this blog post, we took a look at the basic concepts of Reactive Streams. In part 2 of this blog post, I'd like to tell you about how we use Reactive Streams with Armeria.

What is Reactive Streams?​

In this post, I'd like to introduce the basic concept of Reactive Streams, and how to use Reactive Streams with Armeria, the open-source asynchronous HTTP/2, RPC, REST client/server library. Let's begin by examining what Reactive Streams is.

The official homepage of Reactive Streams defines it as follows.

Reactive Streams is a standard for asynchronous data processing in a streaming fashion with non-blocking back pressure.

Let's take a closer look at what they mean by "processing in a streaming fashion," "asynchronous," "back pressure," and "standard."

This November, accompanied by 3 other members of the Shop team, I attended Devoxx Belgium 2019, held in Antwerp, Belgium - the birthplace of Devoxx and most populous city of Belgium.

Hi, there! Do any of you need to make lots and lots of commits to turn your GitHub contribution calendar into a pastureland? If that's the case, I proudly present Armeria Sprint! Let me give you some ideas on what Armeria Sprint is and share reviews from our enthusiastic participants.

You've probably come across a sprint at technical conferences such as PyCON Development Sprints before. Or, you might just find the term, sprint, familiar because it appears in Agile software development. You might still wonder, "What is an open source sprint anyway? What's up with Armeria Sprint?"

Hello to the readers! I'd like to share with you the first ever Armeria Contributor Reward Event and how it went. For this posting, I'm not going to elaborate on the technical aspects of Armeria. To learn more about its technology and features, please visit the official website for Armeria.

The Armeria project was initially developed by LINE but went to open source later. Even though the project was initiated by LINE, Armeria is where it is now thanks to participation from many passionate contributors. That is why we organized this Armeria Contributor Reward Event, to express our gratitude to all of the contributors.

Let me first give a quick summary of what open source contribution is.

As some of you know already, LINE has been actively open-sourcing projects including Armeria and Central Dogma. Today, I'd like to share a bit about Armeria and setting up a simple web server using Armeria. To follow the instructions, you need to have Java and IntelliJ IDEA installed, which can be downloaded from the following links:

• Java Development Kit
• IntelliJ IDEA