In the previous post, I described what a cluster is and how to setup a RabbitMQ cluster on Raspberry Pi with a few Zero W’s. I’ve built a 5 node cluster, with one master and 4 followers. But this is not enough, I’d like my cluster to be accessible from a single location, it doesn’t really matter which node my applications connect to, since I would work only with HA or Quorum queues. For the latter, a new blog post is coming up where I’ll go through exhaustive details on these queues, their pros, cons and usage examples.

Introduction

In this…


In this blog post I will show you how to build and configure a 5-node Raspberry Pi cluster and use RabbitMQ’s clustering capabilities on the above to scale the message broker horizontally.

Introduction

Experimenting with Pi clusters is something that I have been thinking a lot lately. I decided to build a small Pi Zero W cluster for fun and experimentation, in order to fiddle around with messaging mechanisms such as MPI or to manage Kubernetes or RabbitMQ clusters. In this post, I’m going to talk about the latter.

Requirements

You need to purchase some hardware if you intent to fully follow…


In part 1 I demonstrated how to create a simple consumer and producer using ASP.NET Core Hosted Services. In this part, I will cover everything that happens under the wraps, the communication between the client and the server, the connection, the message publishing and consuming.

AMQP

AMQP is the protocol that RabbitMQ uses to communicate with client applications. Aside from the fact that AMQP defines the wire protocol for RabbitMQ to communicate, it also provides some logical model that comprises of classes and methods which RabbitMQ adopts in its core functionality.

In its core, AMQP defines three components that are very…


Having a system which is composed by distributed applications is a great idea, but a way to communicate with each other is required. A very popular architecture is the so called MDA or Message Driven Architecture, where a system is composed from autonomous components that communicate with each other via messages. The part which facilitates communication is the message broker, effectively decoupling applications, which don’t communicate directly, rather they publish messages to the message broker and the latter is responsible to forward them to interested parties, i.e. other applications.

A message broker that is particularly powerful and interesting is RabbitMQ…


Introduction

Writing readable and declarative code in JavaScript, how nice it would be! 😆

I know, readable and declarative don’t go in the same sentence when talking about JavaScript, but should it be always like this? The community has been looking for ways to improve these problems with the language for years.

Since Babel 7.0 there have been a few proposals implemented that lean towards the readable and declarative JavaScript goal. I’m sure you have heard about the pipeline operator, but if you haven’t then it’s fine, this post will guide you through. This operator is syntactic sugar with the intention…


Introduction

Working with types sometimes can be very tricky for a developer, regardless of the employed programming language. Surely, many professionals have a story or two to share on this. Types can be tricky beasts and it’s not uncommon to be accompanied with few surprises and often sinister quirks which can cause all kinds of trouble. In this post, I want to discuss about boxing & unboxing value types, the performance penalty of this technique and ways to avoid this altogether when applicable.

I know there are plenty of resources all over the internet, where lots of people discuss about boxing…


What is the resource owner password credentials grant? How can I secure my Angular client using OAuth and JWT bearer tokens? In this post I will focus on the resource owner password credentials grant, a different kind of credential flow supported by the OAuth protocol, and how it can be used to secure certain resources on an Angular application. Similarly to previous post, I will create the authorization server from scratch, then the resource server, a simple ASP.NET Core RESTful API, and finally the Angular 6 application, with all the bits and pieces required to prevent unauthorized access.

Source code

Code outlined…


For many years I thought that working hard was the way to go. Just make some TO-DO lists, pick work items in order, carry the task on and move to the next. This was my style and I thought this was the proper way. However this proved to be not that great plan, as I had a hard time tracking my progress, maintain focus on tasks at hand, while burnouts occurred more often than usual. On top of that, health issues risen to make things worse, degrading my focus even more. There were times that I was at terrible shape…


What is OAuth 2.0 and how its flows can be applied for securing my applications? What does a token do and how it is useful in securing API’s? Is there any way to implement all these nice and easy in ASP.NET Core? In this post I will cover these topics, by first discussing about why token based security is so successful in security scenarios, and the OAuth protocol play in this. We’ll see more closely one of OAuth flows, the client credentials flow and implement it to secure an ASP.NET Web API application.

Source code

Source code outlined in this article can…


Since the release of 7.0 version for C#, we’ve seen many small, yet useful features added to the language, aiming to aid developers, directly or indirectly. A new keyword was added in version 7.2, the in keyword, which makes the reference semantics of the language richer. In this post, I will explore this new keyword, along with readonly structs and the ref readonly modifier.

Source code

Code outlined in this article can be found on my GitHub repository.

How to enable C# 7.x features

To enable C# 7.x features in your project, you can do this via the project properties. In Visual Studio, right click on the project…

George Dyrrachitis

Hi there, I am George, an experienced software engineer, hobbyist electronic engineer, writer, clean coder and adventurer! http://codereform.com

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