I’ve been recently drawn twice into an open discussion on when to throw exception in application’s logic. I’ve had my opinions, others have theirs but what lead me to this post is that such fundamental topic is extremely opinionated, even among same language/environment developers. In next few paragraphs I’ll try to sum up major proposed approaches of using exceptions (both those which abuse them ...

Od pewnego czasu chodził mi głowie pomysł by napisać coś o DDD. Tak się złożyło, ze u mnie w firmie powstaje element systemu o nazwie Audit, który będzie służył do zarządzania (planowanie, wykonanie, raportowanie) audytami. Zdecydowałem się pokazać na blogu jak napisać taki system w oparciu o reguły DDD (głównie ze względu na to, że w obecnym projekcie nie korzystamy z DDD). Aby urealnić cały proces, wymagania które będziemy implementować będą pochodzić z rzeczywistej domeny. Oczywiście będzie ...

odcinek DevTalk to nie przelewki, oj nie. Dzisiaj trochę… potaplamy się w błocie. Do rozmowy zaprosiłem Jarosława Pałkę: znanego i uznanego programistę, architekta, managera, team leadera, prelegenta, bloggera i co tam jeszcze. Spotkać możecie go na bardzo wielu konferencjach, gdzie opowiada o Javie i ciężkiej orce w naszym zawodzie. Na Twitterze: @j_palka.

It’s been quite a while since I’ve started gathering some knowledge about the microservices architectural pattern that’s been on a hype recently. After reading many articles, some books like Microservices in .NET Core and talking with smart guys in the Devs PL Slack channel, I’ve eventually decided that the time has to come to try to make the microservices happen in the real world project. That’s the beginning of my journey into the distributed programming and architecture, so please keep that in mind wh...

All right, after a few short breaks, I’m finally ready to continue our journey, during which we discover Command Query Responsibility Segregation pattern along with Event Sourcing. In a previous part, we discovered the role of events and ES in our application and to be honest we’re almost done! But before that, we need to focus a little bit on transporting our commands and events. That’s why today’s post will be dedicated the buses. Okay, let’s start!  RabbitMQ and EasyNetQ To accomplish our task, we n...

Reading time ~3 minutes This is a fifth part of a series:part 1 - Why schedule and procrastinate jobs?part 2 - Overview of Hangfiepart 3 - Scheduling and Queuing jobs in Hangfirepart 4 - Dashboard, retries and job cancellationpart 5 - Job continuation with ContinueWithpart 6 - Recurring jobs and cron expressions Part 3 covered almost all functions in BackgroundJob class except for ContinueWith functions family. So here we go :) The fact that it has the same name as a System.Threading.Tasks.Task funct...

Reading time ~2 minutes This is the third part of a series discussing job scheduling and Hangfire details:part 1 - Why schedule and procrastinate jobs?part 2 - Overview of Hangfiepart 3 - Scheduling and Queuing jobs in Hangfirepart 4 - Dashboard, retries and job cancellation This part will focus on the basic scheduling API of Hangfire. The easiest way to create a fire and forget job is by using the classHangfire.BackgroundJob and its minimalistic (and this is a complement) API of static functions:Enqu...

So far we learned about the whole concept of Command Query Responsibility Segregation (CQRS) and Event Sourcing. We also implemented domain objects which Aggregate consists of, and we expressed user’s intentions using Commands executed by Command Handlers. Today we’ll discover the role of events, and more importantly, we’ll introduce Event Sourcing to our Awesome Calendar project. One more thing. As I mentioned in one of the previous parts, I’m currently working on this project wich means that some code ...

Reading time ~2 minutes In the previous post I’ve wrote about why I think the ability to schedule tasks for later execution is a fundamental technical feature, but also a must have from a business point of view. We are passed the whys, so lets get to the hows. The answer is simple - Hangfire. I’ve wrote about it here, here and here, so yeah, I like it. Hangfire is an amazing library. It has proved itself in my pet project (cookit.pl) and in a huge ERP system that we are building at work, where we repla...

So far we got acquired with a theorythat stands behind the CQRS and Event Sourcing. Moreover, we implementeda (business) heart of our calendar application consisting of a domain objects. Today we are going to reveal next two pieces of our puzzle – Commands and Command Handlers. Once again, I encourage you to share your opinions and suggestions in the comments (if you have any).  Commands So, what exactly the commands are? In short, these objects represent intentions of a user. They are in fact imperati...