DEV Community: Digital Craft Workshop

How I Upgrade my Code-Style of MediatR Pipeline using .NET 6

Digital Craft Workshop — Wed, 08 Jul 2026 15:06:44 +0000

SOFTWARE ARCHITECTURE & REFACTORING

How I Upgrade my Code-Style of MediatR Pipeline using .NET 6

I want to share with you how .NET 6 features with the new MediatR.Extensions.AttributedBehaviors NuGet package helped me polish my MediatR pipelines.

What is MediatR

It is a popular library for C# created by Jimmy Boggard, which can be described as a simple Mediator Pattern implementation in .NET. MediatR NuGet package currently has almost 50 million downloads and still rising.

Wiki page on its GitHub says:

MediatR is a low-ambition library trying to solve a simple problem — decoupling the in-process sending of messages from handling messages.

The word in-process is essential. This is not a Message Broker as Kinesis or RabbitMQ. This is about sending the message from one place and handling such message in a different place, but still in one process.

I use MediatR for decoupling Command and Query Requests. So In my case, the MediatR message is Query or Command, depending on the direction of data flow. This architectural design is called Command-Query Separation, and I am explaining it in the first paragraph of blog-post 3 CQRS Architectures that Every Software Architect Should Know.

You can see how I can handle HTTP GET by defining a GetWarehousesQuery as a MediatR request (message), and GetWarehousesQueryHandler as its Handler in the code sample below.

Warehouses Query Handling

Upgrade Code with .NET 6 Features

Records

Actually records are with us since .NET 5 and C# 9, but it is related to the topic of a blog post so that I will introduce them to you too. The feature called Records. Records introduced a shorter syntax for defining an immutable class. I find helpful when I am declaring Command or Query class.

Look at line 8. The definition of GetWarehousesQuery is now one-line code. I like to have Query and Command classes with theirs Handler classes in one place, which makes my code cleaner.

There is a drawback. You will not be able to change the value of any property after Record initialization. It is an immutable object, and the setter of every property is defined with the init keyword.

Global Usings

Another sugar feature of .NET 6 is Global Usings. The new keyword global before Using directive is making it possible not to include using MediatR in every file where we are implementing interfaces from the MediatR library.

Global Usings are project-scoped, so I recommend you to create just one dedicated file for them in the root of the project folder. Define your Global Usings only there. It can be a mess once you start to write global using in a random file.

Let’s create a GlobalUsings.cs file with this line of code:

global using MediatR;

Now, we can remove using MediatR; from the code sample.

File Scoped Namespaces

File Scoped Namespace means defining one namespace per file without curly brackets. So our code sample can be even cleaner. Take a look below.

Query and Handler in one short file. That’s how I like it.

Upgrade Code with MediatR Attributed Behaviors

MediatR Pipeline

Before moving to my last upgrade, I need to explain what MediatR Pipeline is. It is a pipeline defined for one MediatR Request (message). Pipelines execution starts with Mediator.Send method invocation and passing an object of MediatR Request into it.

Side note: if you enjoy small, practical ways to keep code clean like this, I share short free lessons in The Claude Code Memory Starter — a tiny email series you can join in one click.

Simple pipeline

Pipeline Behaviors

MediatR has a feature called Pipeline Behaviors. Behaviors can be attached to the pipeline by defining a proper interface implementation.

Pipeline with behaviors

You can attach Behavior before or after Handler, depends where you will invoke the next() delegate. A typical example can be a Validation Behavior that will validate the MediatR Request form before Handler.

Now some code. This is my new CreateWarehouseCommand pipeline. The code in the Handler is not vital for proof of the concept. What it does is to persist the new Warehouse record into the database.

Now let’s define Validation Behavior.

The ValidateCreateWarehouseBehavior will be executed before Handler because we are invoking next delegate after validation. If the await next() was at line 14 before if, Handler would be invoked before validation. This is how you can manage the position of Behavior towards the Handler or another Behavior in the pipeline.

Behaviors have to be registered into the DI container manually.

services.AddScoped>, ValidateCreatedWarehouseBehavior>();

By the way, if you have multiple Behaviors for one pipeline, their order of execution is defined by order of registrations into the DI container. This is an unpleasantly hidden way of behaving by MediatR. But I have a nice fix for it in the next paragraph.

MediatR Attributed Behaviors

The last upgrade is the extension library for MediatR called MediatR Attributed Behaviors. The library helps you remove the responsibility of manual DI registrations of Behaviors from the developer. Also, you can see the Behaviors of your pipeline right over the MediatR Request definition. Take a look at the last code sample.

Another power of this extension library is defining the order and scope of behaviors and passing it as other parameters.

[MediatRBehavior(typeof(MySingletonPipelineBehavior), serviceLifetime: ServiceLifetime.Singleton, order: 1)]

public class MyQuery : IRequest

Sources

Last Words

I appreciate your attention. I have a list of non-restricted links for each of my blog-post here. I am part of the Itixo company organizing the biggest .NET conference in Central Europe, Update Conference Prague.

How to Implement Azure Functions in any Language with Custom Handlers

Digital Craft Workshop — Mon, 06 Jul 2026 15:10:41 +0000

How to Implement Azure Functions in any Language with Custom Handlers

Introduction of Custom Handlers with Demo using Go Language.

Azure Functions with Go Language

Introduction

Every Azure Function has its handler. Azure Functions supports handler implementations in many different languages but they may not provide a native implementation in your favorite language. That is where Custom Handlers comes at the scene.

The language of your choice must support HTTP communication because Custom Handler is a web server that receives events from Functions Host modified into HTTP requests with JSON payloads.

Communication Diagram

Functions Host is a bunch of JSON configuration files where you will define which trigger and bindings you want to use and of course the path to the executable file, which is our Custom Handler (Web Server).

Once the Trigger activates by event, the Functions Host sends a request payload to the Web Server. The payload can hold trigger and input binding data.

The Web Server invokes the function and possibly returns a response payload. A response payload can be used for output binding.

Demo

The source code can be found on my GitHub.

Things you Need

Create Project

Location of Create New Project Button

Click on the button highlighted in the image to create a new project.
You will be asked to choose basic settings. Select Custom language, HTTP Trigger, HttpExample as a name of the function, and Anonymous authorization level to define Function Host.

Create a Handler

Create a file in the root folder and save it as handler.go.
Copy/Paste this code into the file.

The function helloHandler is printing a simple message as an HTTP response. The form of the message depends on the value of nameparameter in the HTTP request.

If the value name is set, the response will be:

Hello, {name}. This HTTP triggered function executed successfully.

If the value name is NOT set, the response will look like this:

This HTTP triggered function executed successfully. Pass a name in the query string for a personalized response.

3. Open a command line or PowerShell and compile Custom Handler into an executable file named handler.exe by using this command (installed Go):

go build handler.go

Modify host.json

Now you need to specify the file path for customHandler:defaulteExecutablePath property in host.json. If you created the *.exe file in the root folder, you can set the value to handler.

You also need to set the value of customHandler:eneableForwardingHttpRequest to true.

On a side note — if you like getting your tooling set up properly like this, I put together a short free email series, The Claude Code Memory Starter, on giving AI coding agents a persistent memory.

Run the function

Open a command line or PowerShell again and run this command (installed Azure Function Core Tools) in the root folder:

func start

2. Navigate to the following URL to execute the function:

[http://localhost:7071/api/HttpExample?name=medium](http://localhost:7071/api/HttpExample?name=medium)

If you get a similar response as me, you were successful.

3. You can also take a look into the console and see if your function was executed.

Summary

We found out what Custom Handlers of Azure Functions are, how they work, and how we can easily implement them with Go language. As a next step, I would recommend that you should try to publish function into the Azure.

If you like the article, give it a few claps. Thank you for your time.

If a topic like this is your kind of thing, you might also enjoy my free email series The Claude Code Memory Starter — a few short lessons on giving AI coding tools a memory that sticks.

Sources

Microsoft documentation.
Pluralsight course by Mark Heath — Microsoft Azure Developer: Implement Azure Functions.

3 Things that Change my Way of Thinking in 2020

Digital Craft Workshop — Sat, 04 Jul 2026 15:19:33 +0000

3 Things that Change my Way of Thinking in 2020

This is a list of things that completely changed me in 2020, and it was not the COVID-19.

This year is hard for all of us. When everybody is scared of how global warming affects humanity's future, other catastrophes came by. Large fires in Australia, COVID-19 Pandemic, American Riots, and recent events, the Islamic state’s strikes in France and Austria.

But from my individual perspective, I love the year 2020. This year was groundbreaking for my career. My long-term relationship with the love of my life could not be better, and I doubled my incomes in nine months. Here is what happen.

Entrepreneurship

Last year was the last time I was an employee. I quit and concluded a new contract with the same company I worked for, but this time as a hired entrepreneur.

Becoming an entrepreneur was not my idea. The origin of it comes from the CEO of the mentioned company and also my good friend. “It will suit you and open doors for you. You’ll see.” He told me. And in a few months, I find out he was right.

In the spring, the company's IT specialist, where my beloved works, suddenly end his contract, and that company needs to find someone immediately to take his place.

Once you are an entrepreneur, you can have as many customers as you can handle. So I immediately took his place and migrated all of the company’s IT obligations under my wings.

After a tough week of work, the work was done, and now it cost me a few hours of work every month, and I am paid more than well. I couldn’t achieve it if I stay an employee.

Entrepreneurship brings you the freedom to do more and help others more. It unlocks a different way of thinking about work-life.

Psychology

I am Youtube addicted. Especially when it comes to stand-up comedy or TED talks. Someday in February, I came across the famous interview of Cathy Newman with Dr. Jordan B. Peterson. The interview topic should be the doctor’s new book, The 12 Rules for Life — An Antidote to Chaos.

From my perspective, it was obvious that the interviewer does not read the book nor read it with an open mind. Peterson’s comments on young men’s mindsets touched me, and I decided to search for another his interviews or lectures.

Therefore, I found out that he uploads all of his psychology lectures for free, and now I can’t be more thankful. It answers so many questions every young man has. I recommend you read his book or play one of those videos.

The main thought I learn from him is that life's meaning can be found in responsibility. How much responsibility you can take, that much is your life meaningful for you, your loved ones, your community, and even for the world.

Take responsibility for your life on your shoulders. Stop accusing the law, the rich people, or the economy for your problems. You are the one who can change everything in your life.

Don’t wait until some politicians discuss the problems of groups in society you are part of. The solution to your problem can be only one google search away.

Physical Health

I was good at sports in my whole childhood. I played hockey for ten years. Hockey is a big deal in the Czech Republic, and many young men start with hockey at a really young age.

More precisely, I was a goalie. I wasn’t in a stable form, once I catch every puck, once I got 15 goals in one match. Today I think it was unstable self-esteem. In the last two years of my career, I was bullied by the team members for my bad results on the ice.

Suddenly, I quit hockey. It was a busy childhood. Four pieces of training weekly plus match on the weekend in winter and five pieces of training in summer. It was a relief.

Since then, I never workout for more than one week. But this year, I find out through my study that mental health relies heavily on physical health, and I want to work a whole day and don’t feel tired the next morning. So I want to do something about it.

First, I cut the amount of alcohol consumption to almost zero. As a Czech man, I don’t count one beer after lunch into it. But these situations or rarer than ever before.

Second, I talked to my girlfriend about the food, and she taught me the basics of balancing my daily food income. Now I am eating mashed eggs every morning and dine a tuna salad every evening, and I feel so light every morning I couldn't believe it.

Third, I am daily consuming a dietary supplement. As a central-Europeans, we are lacking Omega 3 acids from seafood, and almost every individual lacks Magnesium. Plus, some complex vitamins, and I feel healthy like never before. But this is a recipe for me, read something about it or talk to your doctor before you take any action.

Now I feel physically capable of anything, and I even started with a light daily work-out. It has been two months now, and my back hurts are gone.

Summary

Educate yourself. Take responsibility for your life. Don’t rely on any system or anyone else.

Study your body more and find your own recipe to improve it. We are all ecosystems as our planet. We want all to take care of the planet more, but how about start with yourself. Once you have no limits, you will help the planet more than the only wave with signs in protesters' crowd.

No More Mess in my Head Around Phrases Related to Identity in Computing

Digital Craft Workshop — Thu, 02 Jul 2026 15:04:36 +0000

Azure

No More Mess in my Head Around Phrases Related to Identity in Computing

What is Identity? Azure Active Directory is just Active Directory in Azure? Microsoft Graph is a Data Visualization Framework or What?

Credits of logos for [Microsoft](https://microsoft.com).

Identity

What is Identity in Cloud

Identity is a unique identification of an object. Such an object can be a human being, machine, or a combination of it. When we talk in the cloud computing context, identity means a set of properties about this object stored in the cloud's datacentre.

Introduction to Cloud Computing

Cloud computing is the present and future of software utilization, development, and hosting. Let me introduce you to its…levelup.gitconnected.com

Identity & Access Management

Identity Management (IdM) and Identity and Access Management (IAM) is an interchangeable term in identity access management. So if you are reading about one, you are probably reading about the second term too.

IAM is a framework of policies that tell what users can do in their restricted area and what he needs from the user to operate properly. Such systems identify, authenticate, and authorize individuals or hardware applications to use restricted resources.

IAM exists in the world without the internet too. It appears in different forms. For example, the “Staff Only” label at doors in markets, id card pinned at employees suit, or doorman as a profession by itself. Even your dog protecting yard is some Access Management of your property.

Dog protecting an off-limits area.

Every IAM operates in its defined context. The context of IAM specifies the number of properties it needs from the Identity. For example, every patient has a folder with properties about his identity at the doctor's office.

Identity Platform

Identity Platform is an IAM service provided by third-parties such as Microsoft or Amazon (Amazon Cognito).

Using External vs. Internal Identity Platform

External identity platform (IP) helps you build applications without its own identity management service such as Identity Server. Authorization and authentication can be handled externally, and the only thing you need to do is integrate between your system and MIP.

Integration with an external identity platform does not make sense if you are not using third-party software, and most of your companies applications were built in-house. For example, if the whole company is using Windows and Office 365, it does make sense to integrate your system with Microsoft Identity Platform.

Microsoft Identity Platform

The Microsoft identity platform helps you build applications your users and customers can sign in to using their Microsoft identities or social accounts, and provide authorized access to your own APIs or Microsoft APIs like Microsoft Graph. — docs.microsoft.com

Components of the Microsoft Identity Platform?

OAuth 2.0 and OpenID Connect standard-compliant authentication service. — Possibility of secured work or school accounts authentications.
Microsoft Authentication Libraries or MSAL. — Microsoft MVP and my friend Daniel Krzyczkowski have great GitHub repo with guidelines for using MSAL.
Application management portal. — Registration and configuration of applications in the Azure portal. Management is also possible through PowerShell or configuration API.

Microsoft Graph

Microsoft Graph is the gateway to data and intelligence. It provides a unified programmability model that you can use to access the tremendous amount of data in Microsoft 365, Windows 10, and Enterprise Mobility + Security. — docs.microsoft.com

Downloaded from [https://docs.microsoft.com/en-us/graph/overview](https://docs.microsoft.com/en-us/graph/overview). Credits for [Microsoft](https://microsoft.com).

Mostly when you are sign-in or up with your Microsoft account and you tracked the communication, you will find out that the browser is talking a lot to https://graph.microsoft.com, which is a single endpoint of Microsoft Graph API.

Side note: I also write short, free lessons on getting more out of AI coding tools — if that's your thing, The Claude Code Memory Starter is a tiny email series you can join in one click.

Once you are integrating your application with the Microsoft Identity Platform, you will communicate through this API. You can do it directly or with MSAL, which encapsulates the HTTP communication with API.

Active Directory vs. Azure Active Directory

Active Directory

Active Directory (AD) is a directory service developed by Microsoft for Windows domain networks. — Wikipedia

Physically it is nothing else than an on-premise private server. Active Directory or Active Directory Domain Services is a database of your company’s users and computers. It provides authentication and authorizations for applications or users. It uses dinosaur protocols like Kerberos and NTLM.

Azure Active Directory

Azure Active Directory (Azure AD) is Microsoft’s cloud-based identity and access management service. — docs.microsoft.com

Credits of the logo to [Microsoft](https://microsoft.com).

Azure Active Directory (Azure AD) takes AD approaches, expands them, and brings them to the next level, the cloud level. Azure AD provides organizations with an Identity as a Service (IDaaS) solution for applications across Azure and on-premise servers too.

Azure Active Directory vs. Microsoft Graph

Azure Active Directory is a security token server which analogous to a directory in the Cloud. When organizations want to move their on-premise directories to the cloud and make their applications securely accessible anywhere from the internet, they can take advantage of Azure AD.

Azure AD has two versions. The V1 endpoint and the V2 endpoint and Microsoft Identity Platform is made of the V2 endpoint, documentation, and application registration tools like App Registrations in the Azure portal. The Microsoft Identity Platform contains part of the Azure Active Directory.

Sources

More about Azure

Introduction to Cloud Computing

Cloud computing is the present and future of software utilization, development, and hosting. Let me introduce you to its…levelup.gitconnected.com

How to Create a Free Azure Account Step by Step

Guide for creating a free Azure account. What services can you use for free? What is Directory or subscription and what…levelup.gitconnected.com

How to Choose the Azure Region

What should you consider before choosing Azure Region? How Microsoft geographically divide datacentres position to…danielrusnok.medium.com

Understanding the Azure Resource Groups and Azure Resources

Also with Guide How to Create your First Azure Resource Group and Add your Azure Resource Into it.danielrusnok.medium.com

Daniel Rusnok’s Newsletter

Every month I will send you an email about a list of my newest articles. It will be, of course, the friendly links…www.danielrusnok.com

If this helped clear things up, you might also like The Claude Code Memory Starter — a short, free email series, one bite-sized lesson at a time.

Understanding the Azure Resource Groups and Azure Resources

Digital Craft Workshop — Tue, 30 Jun 2026 15:04:02 +0000

AZURE & CLOUD

Understanding the Azure Resource Groups and Azure Resources

Introduction to Azure Resource Groups and Azure Resources. How they are related and what are they capable of.

Introduction

Once you have your Azure account and access into Azure portal, you are ready to create your first Azure Resource Group and add some resources into it. You will also need a subscription. If you don’t have any of those things then I would recommend you to see my tutorial How to Create an Azure Account.

How to Create a Free Azure Account Step by Step

Guide for creating a free Azure account. What services you can use for free? What is Directory or subscription and what…levelup.gitconnected.com

Azure Resource

Azure Resource is the manageable item in Azure. It includes things like Virtual Machines, Azure Storage Accounts or Azure Web Service. The Azure resource is an instance of Azure Services.

There are three basic divisions of Azure Services.

Infrastructure as a Service (IaaS)
Platform as a Service (PaaS)
Software as a Service (SaaS)

You can find more about divisions in my Introduction to Cloud Computing article.

Introduction to Cloud Computing

Cloud computing is the present and future of software utilization, development and hosting. Let me introduce you its…levelup.gitconnected.com

Whenever Azure Service you want to use, you will find the resource for it. But first, you need the Azure Resource Group.

Side note: if you also lean on AI tooling while you build, I share short, free lessons on getting more out of it in The Claude Code Memory Starter, a tiny email series you can join in one click.

Azure Resource Group

Azure Resource Group is basically a container for Azure Resources. The resource can only exist in one resource group. Resources are not limited by region and can be from different regions. The resource group is not a physical grouping of resources. I covered the topic Azure Regions in my article How to Choose Azure Region.

How to Choose the Azure Region

What you should consider before choosing Azure Region? How Microsoft geographically divide datacentres position to…medium.com

Resources in the resource group shared the same lifecycle, which means you can deploy, update and delete them together. Such operations are possible to do at the resource level too, but general guidance is that if the resource needs to exist on the different deployment cycle, it should be in another resource group.

Resources and resource group can communicate across. For example, you have the Azure Web Service in one resource group and still can communicate with the Azure SQL Database from different resource group.

Azure Resource Group icon created by [vecta.io](https://vecta.io/symbols/27/microsoft-azure-mono/110/resourcegroup)

The resource group is also suitable to set security boundaries for the whole group. What can be done with security can also be done with access control. You are able to assign access for the whole group and not for every resource separately.

The pretty cool feature is an export Infrastructure-as-code using Resource Manager Templates. But this I will save for the next time.

Sources

Daniel Rusnok's Newsletter

Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…www.danielrusnok.com

If this was useful, you might also enjoy The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

How to Choose the Azure Region

Digital Craft Workshop — Sun, 28 Jun 2026 15:04:43 +0000

AZURE & CLOUD

How to Choose the Azure Region

What you should consider before choosing Azure Region? How Microsoft geographically divide datacentres position to secure high availability and disaster recovery?

Introduction

Most of the Azure resources demand the region to be specified. I was struggling with this choice and always picked the one nearest to my location. Lately, I found out that the choice should be made more based on the physical location of resource users than the location of me, and I changed it.

After a while, one question still bothers me — Does the choice of region matter more than I think? Then, I started to dig deeper into this topic and boy. It really matters, especially on enterprise application levels.

Azure Regions

Azure regions approximately specified Azure Resource’s physical location. It is not the precise location of the machine your resource is hosted on but it’s more the scope where you expect the majority of requests. So, the first question you should ask yourself is:

Where is most service users?

Some services are not available in every region. You can find out which service is available where at Microsoft webpage. Few of services from Azure portfolio is defined as global. Which means they are highly available in every region. For example, Azure Active Directory.

[Source](https://azure.microsoft.com/cs-cz/global-infrastructure/services/)

If you are designing the whole cloud infrastructure, you should check the availability of each service in the region you planned to use. So, the second question you should ask yourself is:

Is each of service you need available in the region you want to use?

Another reason to pick different region can be regulatory and compliance reasons with regards to data residency. Data residency refers to the physical location of information in environments such as the cloud or on-premises servers.

If your company or industry is heavily regulated, you might need to look at the specific requirements. There is a chance you might need to do some extra encryption of your data. This is a tough topic and Microsoft created a document to help you with it. Take a look here.

We figured out the third question:

Do I need to consider regulations or compliance reasons relating to data residency?

Azure Geographies and Azure Region Pairs

Side note: if you also lean on AI tooling while you build, I share short, free lessons on getting more out of it in The Claude Code Memory Starter, a tiny email series you can join in one click.

Now, when we know, what we need to consider when choosing the region, let’s talk more about Azure geographies and region pairs.

Image download and converted to PNG from [https://azure.microsoft.com/en-us/global-infrastructure/geographies/](https://azure.microsoft.com/en-us/global-infrastructure/geographies/)

Azure Geography contains one or more regions. Every geography has its specific data residency and compliance requirements. There exist some automatic processes like replication which you might want to forbid. Go to Microsoft’s webpage with geographies and use filter to get Azure compliance offerings and data residency information for your chosen geography.

Snipped out from [https://azure.microsoft.com/en-us/global-infrastructure/geographies/](https://azure.microsoft.com/en-us/global-infrastructure/geographies/)

An Azure Region Pair is a relationship between two azure Regions within the same geographic region for disaster recovery purposes. The datacentres in region pair are tactically minimally 300 miles apart of each other. It is a reasonable distance from possible natural disaster or blackout events.

Microsoft decided which regions are impaired and you can’t decide it for yourself. To ensure high availability, Microsoft always updates only one region from pair in one time. During possible multiple outages, there is one region prioritized for disaster recovery.

Some services have a built-in option for failover and in an inconvenient event, it handles the situation by itself for you. Some services do not have a failover option. You should design your own solution for disaster recovery and high availability for such services. Keeping in mind which regions are in pair helps you to design such solutions.

Azure Availability Zone

Availability Zones are unique physical locations in a single region. It can contain more datacentres with independent power, cooling, and networking. Minimum for one region is three separated zones.

When you are creating a Virtual Machine Service, you can specify the availability zone. That gives you the power to create a more virtual machine in different zones and setup load balance or data replication between them. This can protect you from a natural disaster in one region.

Some services like Zone Redundant Storage will replicate your data automatically across zones and you don’t have to take care of it.

Sources

Daniel Rusnok's Newsletter

Every month I will send you an email about with a list of my newest articles. It will be of course the friendly links…www.danielrusnok.com

If this was useful, you might also enjoy The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

How to Create a Free Azure Account Step by Step

Digital Craft Workshop — Fri, 26 Jun 2026 15:06:47 +0000

AZURE & CLOUD

How to Create a Free Azure Account Step by Step

Guide for creating a free Azure account. What services can you use for free? What is Directory or subscription and what type of subscription Azure offers?

official Azure logo downloaded from seeklogo.com

What is Azure

Azure is a cloud provider developed by Microsoft. If you are not familiar with Cloud Computing I recommend you to read my Introduction to Cloud Computing.

Introduction to Cloud Computing

_Cloud computing is the present and future of software utilization, development and hosting. Let me introduce you its…_levelup.gitconnected.com

Creating the Free Azure account

Go to https://azure.microsoft.com/free.
Click on “Start for free” button.
You will be redirected to a sign-in form. You need the Microsoft account. If you don’t have any, created one or there is also the possibility to use GitHub account since Microsoft bought it.

Microsoft sign-in form

4. After your successful authorization you will be redirected to Identity verification by card form. For those who also do not like to give credit card initials, I have a little tip for you. Use service Revolut to create the international bank account for free and then generate a virtual credit card. It is completely free.

Identity verification by card form

5. Now that only remains is checking the agreement, click sign up and your Azure account is created. Congratulations!

Agreement and sign up button

6. If you weren’t have been redirected to Azure Portal, please use this link.

Free Services with Free Account

With your first registration, Microsoft is more than generous to us. You will be provided with:

€170 or $200 free credit for the duration of the first month. When your first month ends, the credit expires and you will be asked to choose one of the available subscriptions. We will talk about them soon.
12 months of popular services for free.
25 services independently for free. Offer might differ in different regions.

The structural list of free services and advantages can be found on the same page which we used for registration. Scroll down and you should find it.

Subscriptions

Quick aside: if you like picking up new tools one clear step at a time like this, I share short, free lessons in that spirit over at The Claude Code Memory Starter — a tiny email series you can join in one click.

One Directory can hold multiple subscriptions. It serves as a single billing unit for Azure resources. This is the most often used subscription types:

Pay-as-you-go — As the title refers, you will be billed monthly for resources you used in the current month. This is an obvious choice after one-month free trial. If you want to use just free services, you have nothing to worry about.
Azure Open Licencing — Credits bought from third-party retailers. You will obtain the code which one you going to apply threw online form in Azure Portal.
Visual Studio Enterprise Subscription — if you are a user of VS Enterprise, you are provided with free monthly credits in the amount of $200.

There are also more enterprise subscriptions which include the Azure support services. What is worth mentioning is that you cannot deploy any service without the active subscription.

If you are not interested in the free trial month, you can immediately upgrade your subscription threw button Upgrade in top left corner of Azure Portal home page.

Upgrade button in Azure Portal

Subscription can also be added threw page subscription. You can be navigated there threw interactive search field at the top.

Search subscriptions

Or, if you are really newbie and doesn’t play with the settings of your homepage, you should be able to see the link to the subscriptions page in Azure services section and also in Navigate section.

Subscription links at Azure Portal homepage

Once you will be at Subscriptions page, use the button Add. You will be redirected to page with subscription offers. As you can see in the image below, I have disabled the Pay-As-You-Go Select offer button, because my free trial month is still running. But I would be able to upgrade my account threw provide link next to it.

Summary

I hope that everything was clear and you are now ready to create your free account and start to play with Azure. Azure is really huge playground and it is worthwhile.

Sources

Daniel Rusnok's Newsletter

_Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…_www.danielrusnok.com

Level Up Coding

Thanks for being a part of our community! Level Up is transforming teach recruiting. Find your perfect job at the best companies, not just your next job. Click “Apply to join” if you’re a dev or “Start hiring” if you’re a company.

Level Up — Transforming the Hiring Process

_🔥 Enabling software engineers to find the perfect role that they love 🧠 Finding talent is the most painful part of…_jobs.levelup.dev

If this was useful, you might also enjoy The Claude Code Memory Starter — a short, free email series, one bite-sized lesson at a time.

Introduction to Cloud Computing

Digital Craft Workshop — Wed, 24 Jun 2026 15:05:24 +0000

Azure & Cloud

Introduction to Cloud Computing

Cloud computing is the present and future of software utilization, development and hosting. Let me introduce you its basics.

Early Evolution of Cloud Computing

Datacentres in the Past

Until recently, maybe 10 to 15 years in the past, each company had its own datacentres with servers for a different purpose, maybe running on different hardware, and even with a different operating system.

Each of these servers has its own CPU, hard drive, and RAM memory and every one of them need enough resources for utilization at peak time.

It also means, that on average, most servers were really underutilized, and organizations were spending a ton of money on hardware that most of the time was not even used at 10% of its capability.

Virtualization

Then, we started to implement virtualization, which allows us to run multiple virtual machines at a single virtual host (physical server). So, we were able to get more usage out of hardware, cut down space cooling and of course, the costs.

However, even with virtualization, we still had a few disadvantages, such as high upfront cost. So, we needed to buy powerful virtual hosts, which we would then kept for five years for the amortization of cost.

We still had to pay for space in the datacentre, as well as electricity and utility costs for cooling and other server’s needs. Furthermore, hardware maintenance is still required as this can breakdown, network cards can go bad, and so on.

Virtualization is more cost-efficient than dedicated hardware, but there still was space for improvement. This is where Cloud Computing came in.

Cloud Computing

Cloud Computing enables companies to consume a compute resource such as a virtual machine, storage, or an application, as a utility — just like electricity — rather than having to build and maintain computing infrastructures in house. Source.

How to Create a Free Azure Account Step by Step

Guide for creating a free Azure account. What services you can use for free? What is Directory or subscription and what…medium.com

In the cloud environment, you have the cloud provider which owns their datacentre and manages all their hardware, networking and, of course, virtualization. Cloud is fully built on the principle of virtualization. No client has direct access to the hardware. Simply, its virtualized environment.

All resources are pulled together and then shared to multiple clients that all consume that shared hardware. Such clients do not need to know what server they are run on or on how many servers their environment is running. They simply consume a service and the cloud provider is the one making sure there are enough shared resources to handle requirements.

Users select only the services they want to use. Each service has its own definition of utilization. Once you can be billed per user, once it can be per minute. Cloud infrastructure should be self-serviced by the user and provisioning should be fully automated by the cloud provider and delivered at almost instant fashion.

Side note: I send short, free lessons on building and shipping software in The Claude Code Memory Starter — a tiny email series you can join in one click.

Fundamental Division of Cloud Services

Each cloud provider has its own list of services to offer, but these services can be always divided into two basic ones.

Compute Power

Compute power is how much processing computer can do. For example, when you are buying new home computer, you may choose a computer with 8 GB of RAM and the latest processor to run today’s software. But, as a load of computer grows, you will find that it slows down.

With Cloud Computing you can add or remove compute power as you need. This can save your costs, since you are paying only for the resources you use.

Storage

Storage is a volume of data you can store on your computer. Traditional computer has a limited hard drive for space. With cloud computing you can request more storage as you need.

Furthermore, we can divide cloud services more by its user’s needs into three categories.

Infrastructure as Service(IaaS)

IaaS aims to provide control over hardware directly to the customer. This does not mean control over the physical machines. This means full control over hardware threw online interfaces. Customer will gain control over virtual machines, storages, or operating systems.

Common usage:

Load migration.
Storages.
Backups and recovers.

Platform as Service(PaaS)

PaaS is providing an environment for development, testing and deploying of software applications. Target is to create application quickly without infrastructure concerns.

Common usage:

Development framework(Software resources such as Azure Fabric Service).
Analytics and Bussiness inteligence.

Software as Service(SaaS)

SaaS is supplying companies without software focus business. So we are talking about software like Office365 or Skype.

Table of Responsibility

[Source](https://docs.microsoft.com/en-us/learn/modules/principles-cloud-computing/media/5-layer-diagram.png)

IaaS — Requires the most of user’s management over all of cloud services.
PaaS — Requires less of user’s management. Cloud is providing operation system and user is responsible for applications and data.
SaaS — All of responsibility relies on cloud provider.

If this was a useful primer, you might also enjoy The Claude Code Memory Starter — a short, free email series, one bite-sized lesson at a time.

How to Rewrite your Code to Achieve More Flexible Design

Digital Craft Workshop — Mon, 22 Jun 2026 15:03:47 +0000

CLEAN CODE & REFACTORING | SOLID SERIES

How to Rewrite your Code to Achieve More Flexible Design

The ultimate guide with an example of how to break class and separate concerns using the Single Responsibility Principle

[Clean code](https://www.amazon.com/gp/product/B001GSTOAM/ref=dbs_a_def_rwt_hsch_vapi_taft_p1_i0) _is a software development discipline that aims to raise the IT company’s vitality by introducing practices, principles, and patterns to improve developer’s programming skills. Programmers who follow the_ Clean Code _becomes professionals and leaders in their fields._

Single Responsibility Principle or SRP stands for the idea that every class or module should have one and only one responsibility. In other words, each class or module should do one thing and do it well.

What Means Responsibility in Software Engineering?

Robert C. Martin defined responsibility as a reason to change. Don’t mistake it with the four main reasons to change your software I blogged about before.

Four Reason to Change your Software

Michael Feathers defines four main reasons to change your code in the book Working Effectively with Legacy Code. I…medium.com

This reason to change is more related to module or application features. In an ideal world, one feature’s behavior change means one class or module to modify.

SRP in Unix

SRP is a well-known principle in software design, and we’ve known for decades that this works very well.

Unix is based on this principle of doing one thing and does it well. Unix is based on the command line, so each command is a small executable program. It has a way to compose those executables into larger-scale programs.

The success of Unix continues by the success of Linux, so we know that there are examples of this principle leading to systems that are very stable and very long-lived.

I found a repository with historical commits since 1970 if you are more interested.

Why is SRP Hard to Implement?

On my hunt for the answer, I came across a great Quora answer from user Pawan Bhadauria, and I want to quote the piece of it.

Consider following sentence: “Tihs snetnece is hrad to raed”.

I bet, you will be able to read this sentence since you comprehend the word as a whole rather than linking each alphabet and making a sentence out of it. Though it directly doesn’t relate to the principle but gives a glimpse into how our brain processes things. Our minds are excellent at seeing a set of behaviour and grouping those together, even when those constitute different responsibilities.

We tend to group behaviors by our nature. The human brain’s strength is also a developer’s kryptonite when he is trying to apply SRP.

Indicators of Violation SRP

The most significant indicator is the size of the class or function. Count of physical lines of code measures functions size. On the other hand, the number of responsibilities measures the class size.

“The first rule of classes is that they should be small. The second rule of the class is that they should be smaller than that.” — Robert C. Martin

Troubles to name the class correctly is one of the indicators as well. The name should be maximally 25 characters long without using words like “if”, “and”, “or” or “but”.

Sometimes, problems with naming the class end by raising a point of view and using the most common name that comes up to the programmer’s mind like OrderService.

The order is processed from filling the basket to receiving a receipt, and it can’t be defined with such a simple name.

Tutorial

Prerequisites

The reader should have basic knowledge about Object-oriented Programming or OOP. Basic understanding of Unit Testing is also appropriate, but not necessary. I am programming in C# language, but Java or other OOP language developers should not have a problem understanding the concept.

Introduction of Project

The repository consists of two projects. First one is the Class Library named BusinessLogic. It includes two folders; Before and After.

Folder Before contains the class FileStore, which is taking care of storing messages into text files.

Folder After contains module consists of three class with the very same responsibilities, as a Before/FileStore class. The content of the directory is the resulting representation of applying the SRP process.

The second project Tests also holds two folders with the same names. Each folder has one class with the very same Unit Tests. The test class Before/FileStoreUnitTests is almost identical to the test class After/MessageStoreUnitTests, but its tests aim to the different system under test as its names suggest.

Side note: if you like thinking about the craft itself — when to refactor, when to leave code alone — I share short, free lessons like that in The Claude Code Memory Starter, a tiny email series you can join in one click.

Identifying the Responsibilities

Gist bellow shows how Before/FileStore.cs the class looks like.

FileStore.cs

Most of you can identify what’s the FileStore class responsibilities. First, that should come at the top of your head is Storing Messages.

Another more obvious responsibility is Logging. Both command methods, Read and Save invokes the NLog functions to log what is currently happening.

The last is not that clear so I’ll tell you. It is what I call an Orchestration. The way of control how the previous two aspects play with each other is also the responsibility.

That’s it! We identified all three, and let’s repeat them.

Storing Messages
Logging Events
Orchestrating interactions

Break the Class

Breaking the class is practically an applying of another well-known principle called the Separation of Concerns.

I like Quora answer by architecture mentor Victor Kane to the question “What is Separation of Concerns in Software Engineering?”

Let me quote the beginning of the answer;

The philosophy of separation of concerns in IT is aimed at preventing “pathological” dependencies between code “concerned” with different domains while attempting to isolate all code concerned with a single “concern”.

“..isolate all code concerned with a single concern.” Sounds familiar right? Now, let’s break the FileStore.

I began with the extraction of Logging concerns. The new StoreLogger class encapsulates implementation details about logging events into its methods. The initialization of StoreLogger is in FileStore constructor and methods are called from the same places as where NLog functions invocations were before.

Interstate Before and After of FileStore.cs

StoreLogger.cs

Now, we need to separate Storing Messages and Orchestration. Let’s logically in our minds separate two implementation details; Storage and Data. In our particular case, the storage is a file system, and the data are messages.

When we consider the dependencies, it appears that the messages should be dependent on its storage, but storage does not need to know anything about the form of data. We can achieve it by extracting the orchestration around the message and let concerns about storage on FileStore.

I separated the original FileStore class into the two new classes; FileStore and MessageStore.

After/FileStore.cs

MessageStore orchestrates the messages, logging, and storage processes.

MessageStore.cs

This time I stuck with the word “store” in the name because it is more precise. Sometimes I struggle to pick the right name for the orchestration responsible classes. So usually I choose the word “Processor”, and I add a prefix which defines the responsibility-for example, a MessageStoringProcessor. The MessageStore name sounds more precise.

I would love to hear how you are dealing with this problem.

Summary

We looked at FileStore class and identify its three responsibilities. First, we extracted the easiest one, the Logging responsibility. Therefore, we separated remaining concerns, Storring Messages, and Orchestration, into the two new classes; MessageStore and FileStore.

The repository also contains the project with unit tests which you can try to run and see if any dropped behavior or function. The green test will prove that we did just right.

Daniel Rusnok's Newsletter

Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…www.danielrusnok.com

If this resonated, you might also enjoy The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

How to Dynamically Add Behaviors With Decorator Pattern

Digital Craft Workshop — Sat, 20 Jun 2026 15:04:10 +0000

DESIGN PATTERNS SERIES

How to Dynamically Add Behaviors With Decorator Pattern

Everything you need to know about Decorator

Created by [www.freepik.com](http://www.freepik.com/)

What is the Decorator Pattern?

The Decorator Pattern is a structural design pattern that allows you to dynamically add behavior to a class without making changes to that class. In other words, it uses composition instead of inheritance to add the functionality of an object.

Elements of the Decorator Pattern

IComponent

IComponent is an interface. It is an abstraction of what we want to decorate. You can also use an abstract class.

Component

The component is a class that you want to add behavior. The component needs to implement an interface or extend an abstract class.

Decorator

The decorator class will implement the same interface or abstract class as the Component class.

The decorator’s constructor always takes an object implementing the same interface as a parameter. Then the object of Component is introduced into the class attribute in Component’s constructor. Like this.

When Decorator implements an interface IComponent, you must implement methods SomeMethod() and AnotherMethod(). Into those methods, you can add new behavior.

When you do not invoke an inner method of Component, it is no longer a Decorator Pattern. You will not add new behavior. You will code a new implementation of the IComponent interface.

Multiple Decorators

You are not limited to just one Decorator object per Component class. You can define Decorator which decorates another Decorator which decorates Components and so on. Look at the image below.

Both pictured Decorators must implement both methods defined in the IComponent interface.

Block named Code represents a place in the codebase where I am operating with Component.

The code will always invoke methods of the most outer Decorator firstly. To bubbled into a Component class, you must call the same-titled method of an inner Decorator in every Decorator.

If you want to use new behaviors of both Decorators at the same time, you must change the initialization of the Component object in the calling code. It can be done in three steps.

Initialization of DecoratorTwo.
Initialization of DecoratorOne and passing into the constructor of DecoratorTwo.
Initialization of Component and passing into the constructor of DecoratorOne.

That’s it! You don’t have to modify any more code. The word dynamic gets its value.

Tutorial

Prerequisites

The tutorial assumes basic knowledge of .NET and Object-Oriented Programming.

Introduction of the Sample project

The sample project is a web application that collects data about the location of the Company's cars. An external API provides data.

Your role at the project

Imagine you are working as a support developer, and the Sample project is your responsibility. Suddenly, you have got a phone call from the customer;

“Hello, Mr. AwesomeReader, I would like to report that the data location page ends with the timeout error.”

Or maybe he is not that polite.

created Kues1 — [www.freepik.com](http://www.freepik.com/)

You are going to ask for advice from colleagues. They advise you to measure a time of how long it application takes to collect data.

LocationService class

LocationService class is taking care of requesting an API and serialize collected data into Data-Transfer objects.

Class implements interface ILocationService. The interface contains a definition of the method GetLocation(). The implementation looks like this.

Maybe you get an idea to add a logging code directly into the method. Let me tell you why it is a bad idea.

First, it will make the class a lot harder to read. More importantly, when you are modifying the existing code, you can quickly introduce an error to the application.

Another reason for not doing this is a violation of the Single Responsibility Principle. The meaning of principle can be expressed in one sentence.

A class should have only one reason to change.

Because you are a great developer and thanks to the great author, who tell you why is it a bad idea, you decide to use Decorator Pattern.

Making that decision allows you to extend LocationService without modification of class. This reminds me of another SOLID principle and it is an Open-Closed Principle. The main thought of this principle sounds like this.

Side note: if you enjoy thinking about design patterns and clean, flexible code, I share short, free lessons like that in The Claude Code Memory Starter, a tiny email series you can join in one click.

Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification.

The decorator supports the Open-Closed Principle by its nature. What a great pattern.

Logging Decorator

You are going to create a LoggingLocationService which is the Decorator of your Component LocationService.

Nice. I noticed that you are using a built-in Stopwatch class to measure elapsed time in milliseconds. It’s much better than my solution to deducting two variables with different DateTime.Now values.

Now you need to do a little change to calling code, which you can found in the Index.cshtml.cs class. LocationService initialization looks like this.

You need to replace the new LocationService(apiKey] with

new LoggingLocationService(
  new LocationService(apiKey),
    _loggerFactory.CreateLogger<LocationService>())

and that’s it. You are ready to go.

Story continues

Thankfully of implemented logging, you were able to find a cause of long loading time. You did some magic as developers do and bug no longer exists.

While you were coding, a wild idea came into your mind; “Maybe I can cache the collection of locations into memory and short loading time even more”.

CachingLocationService

After a conversation with teammates, you decide to cache data for one hour. It sounds like a reasonable amount of time. Time for another Decorator.

Looking good. I see you are using a built-in MemoryCache class. Also, there is no need to generate a random cache key because you are loading a whole collection, right?

In the first if statement, you simply try to get the value of locations collection by cache key. If the collection is empty, new data will be loaded. Therefore, you set a new record into the cache with the expiration of the hour.

Now I guess you would like to combine both new decorators. Logging Decorator and Caching Decorator together.

_locationService = new CachingLocationService(
  new LoggingLocationService(
    new LocationService(apiKey), logger), memoryCache);

You wrapped the initialization of LoggingLocationService with the initialization of CachingLocationService. It looks a little bit unreadable. Try to use multiple variables.

var withLocationService = new LocationService(apiKey);var withLoggingLocationService = new LoggingLocationService(withLocationService, logger);var cachingLocationService = new CachingLocationService(withLoggingLocationService, memoryCache)

Much better. When I see code where you can initialize instance with different behaviors, I am using a Builder Pattern. You can explore it, but not now.

The final class diagram after our changes looks like this.

Decorator and Dependency Injection

Before any Decorator implementations, registration into the container of LoggingService in the Sample project looked like an example below.

services.AddScoped<ILocationService>(serviceProvider => 
  new LocationService(apiKey));

In this case, we are using a build-in .NET Core IoC container. This registration means that injected ILocationService via constructor will always provide an instance of the LocationService object. But you want an instance of CachingLocationService.

You can take a code of multiple initializations shown at the end of the tutorial and use it in registration like this.

There is a third option. You can use a great NuGet package named Scrutor. It is an extension of dependency injection in .NET. It adds methods for registration to make registrations more fluently readable. Cool, right?

Decorator in .NET

You can find the Decorator Pattern also in the guts of .NET. A prime example is a Stream class.

At the top of the hierarchy, we have the Stream class. This is an abstract class and requires you to provide implementations for several methods, mainly the Read and Write method. Sounds familiar, right?

Then we have several concrete implementations of the Stream class, including FileStream, MemoryStream, and NetworkStream. Each of these classes would be equivalent to the LocationService class

Finally, we have several classes that act is decorators. These include the BufferedStream, GZipStream, and CryptoStream classes.

How to recognize when to use a Decorator?

Cross-cutting concerns. These are things like logging, performance tracking, caching, and authorization. Whenever you have these cross-cutting concerns come up, you can implement them using a Decorator Pattern.

Another typical situation is the modification of data before being passed into the Component. For example, encrypt and decrypt data or conversion of units.

Build-in shortcut in Visual Studio

There is a built‑in refactoring tool in Visual Studio, either with the keyboard shortcut of Ctrl+R and then Ctrl+I. Visual Studio will create a Decorator class from the selected interface.

Summary

Remember, patterns are just guiding rails, not prescriptive implementation rules. They are not set into stone. Decorator Pattern is dynamic, clean, beloved principles supportive, and you should consider it as a new tool to your toolbox. The sample project can be found at Github.

Daniel Rusnok's Newsletter

Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…www.danielrusnok.com

If this clicked for you, you might also enjoy The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

Four Reason to Change your Software

Digital Craft Workshop — Thu, 18 Jun 2026 15:07:15 +0000

CLEAN CODE & REFACTORING

Four Reasons to Change your Software

Created by [Stories](https://www.freepik.com/stories)

Michael Feathers defines four main reasons to change your code in the book Working Effectively with Legacy Code. I found those few paragraphs interesting, and I would like to share them with you from my perspective.

Four main reasons to change are

Adding a feature
Fixing a bug
Improving design
Optimising

Adding Feature and Bug Fixing

original pictures by [Stories](https://www.freepik.com/stories)

The most typical reason to change software is an adding of the feature. Your software is acting one way, and the boss or client needs it to do something else.

At first, adding a feature may look like an easy task for both sides. Friction between the developer and the task assigner began when the assigner thinks it is a bug, but the developer sees it as a completely new feature.

At the moment when I am writing this article, I am also working on a form-based information system, and new task recently appeared in the mailbox. The client wants me to fix the focus behaviour of textboxes. He thinks that every time he clicks or tabs into a textbox which contains a text, the whole text should be already selected or as he said; “it should be blue”.

selection of text

As the developer, you know that this is not typical behaviour of textbox and you will have to make changes. Depends on the framework you are work with, the task can take a few minutes or a few hours, and you may come out without a solution.

It might seem that difference between adding a feature and bug fixing is just the dilemma about the contrast of the point of view. A task stays the same, and you still have to complete it one or another.

But some companies are tracking developers time, for example, for invoice calculations or quality initiatives. Such difference decides if the company will bill the customer for a new feature or not. Bug fixing can be part of the contract with the customer. In this situation, the determination of difference crucial.

Design Improvement and Optimisation

Created by [Stories](https://www.freepik.com/stories)

First of all, don’t get me wrong. By saying word design, I mean a code design, no design of user interface.

Design improvement is a different kind of software change. It is driven by the goodwill of the developer, no by the boss task.

When we want to alter the software’s design to make it more maintainable, we want software behaviour to keep untouched. By changing a design, we may introduce a bug. Fear of introducing a bug leads to intact code segments which stay the same since the beginning and will rot.

As developers, we grow and knowledge of our craft rise. Time goes, design of new code is better, and one day task will appear for adding a new feature into old code parts. We can clearly say that such situations will once in a while come out. Such a position always motivate me to improve the design, but I am too afraid of dropping behaviours, and I will not do any. Again.

Created by [Stories](https://www.freepik.com/stories)

Refactoring

Developers fear of changing code drives the creation of whole the discipline named refactoring. Refactoring is also the main topic of the earlier mentioned book.

The idea behind refactoring is that we can make the software more maintainable without changing behaviour if we write tests. Tests will serve as watchdogs. If any test fails while you improve a design, it indicates that you unwillingly drop a behaviour.

Code should be cover by the collection of tests which will keep watch on application behaviours. We should refactor in small steps, and continuously run a set of tests that will keep us informed.

The critical thing about refactoring from a change point of view is that there aren’t supposed to be any functional changes when you refactor.

Optimisation

Created by [Stories](https://www.freepik.com/stories)

The optimisation is like refactoring, but with a different goal. We want the functionality to stay the same, but the goal is to increase performance. Optimising can lead to dropping a behaviour and introduction of bugs too. We must apply the very same rules as in the refactoring process.

Summary

Fight between “it’s a feature” and “it’s a bug” is endless. Correct identification of the problem could lead to the rise of the company’s income or vice versa.

Refactoring and Optimizing are essential disciplines of code improvement and reasons for changing code. It has to be done slowly, wisely, and with the collection of tests which are going to watch your back.

One way of improving code design is to take advantage of design patterns. I wrote a few pieces, and you might find an interested in reading them as well.

Decoupling with Chain of Responsibility Pattern in C#

The Chain of Responsibility Pattern allows us to easily separate dependent parts to make code more extensible and…medium.com

How to manage states with State Design Pattern in C#?

Everything you need to know about State Design Pattern in C# at one place.medium.com

Daniel Rusnok's Newsletter

Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…www.danielrusnok.com

If this resonated, you might also enjoy The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

Developers are introverts. Domain-driven design can help.

Digital Craft Workshop — Tue, 16 Jun 2026 15:07:44 +0000

Developers are introverts. Domain-driven design can help to change it.

As developers, we are writing code to build software, but we can’t make good software without talking to clients.

Developers aren’t chatty.

Most of the time software developers are struggling in communication with clients and also with the outer world. Many of us choose this career to avoid meeting with people, and that is why companies hire managers who are doing instead of us.

If you are one of these introverts, then I have bad news for you. You may end up stuck with buggy code forever.

Created by rawpixel.com — [www.freepik.com](http://www.freepik.com)

If you are going to build software for business, you need to understand every detail because you are translating business processes into code. And you don’t want to lose important information in translation.

Domain-driven design intervention

One of the critical pieces of Domain-driven design(DDD) is to encourage developers for better interaction with domain experts. The domain expert is one who knows the client’s business needs and processes.

Developers need to understand their clients more than their partners. If you are a man, you probably are more successful in understanding your client than your precious one.

Photo by yanalya — [www.freepik.com](http://www.freepik.com)

You may say you already talk to them, but maybe in a different language. Maybe you are using your terms like tables in the database rather than domain concepts.

DDD guides us to find a common language with Domain Experts and understand each other at a much higher level.

Ubiquitous language

Ubiquitous. Terrible word. If you don’t know how to pronounce it, this might help [yo͞oˈbikwətəs]. For me, it doesn’t. I had to use Google Translator for listening to the pronunciation. It doesn’t help either.

A simple definition of a ubiquitous language is to come up with terms that will be commonly used when discussing a particular subdomain. What subdomain is, will be introduced in the next paragraph. Hold tight.

There will most likely be terms that come from the business space, not the software world. But those terms have to be agreed by both sides, domain expert and developer. Make sure there is no confusion or misunderstanding created by the terminology used by various members of the team.

Photo by pressfoto — [www.freepik.co](http://www.freepik.com)m

Domain and subdomains

The core domain is a field of study that defines a set of common requirements, terminology, and functionality for any software program. DDD teaches us how to divide the core domain into smaller subdomains.

Imagine a company. It can be divided into smaller pieces, departments, for example. With subdomains, the logic stays the same. They are filled with their complexity, terminology, tasks, and challenges.

Image by Starline — [www.freepik.com](http://www.freepik.com)

Many applications just try to do many things at once and introducing new features getting more difficult. With DDD, you will divide and conquer. By tearing software to separated subdomains, we can achieve dividing problems that are much easier to solve.

The principle of Separation of Concerns(SoC) not only plays a critical role in identifying the subdomains but within each subdomain, we use it as well.

Many applications spread domain logic across the entire project. Across the persistence layer, across the user interface. Such spreading makes it much more difficult to keep all of the business logic consistent.

If you want to keep going on the meta-skill side of building software — I'm publishing short, free lessons in The Claude Code Memory Starter, a tiny email series you can join in one click.

DDD applies an SoC to help direct you by focusing on the domain. Not on details like how to persist data into the database or how to connect to external API. Those become implementation details that you can ve worry about later.

Benefits

The first main benefit is flexibility. Because DDD guides us to focus on small, individual nearly autonomous pieces of our domain, our process and the resulting software is more flexible. We can easily move or modify the small parts with little or no side effects. The project is stable and flexible.

Image by master1305 — [www.freepik.com](http://www.freepik.com)

Another benefit is that code is closely mapped to the customer’s understanding of the problem. DDD gives you a clear and manageable path through a very complex problem. When you look at the code, you can see that it’s generally well organized and business logic all lives in one place.

DDD is not a path for every project, but there are many principles and patterns from which you can benefit. Its real benefit is for complex domains. You can describe domain as complex when it gets challenging to domain experts to express their needs. You know. Like women.

Image by Jcomp — [www.freepik.com](http://www.freepik.com)

DDD provides principles and patterns that help us tackle difficult software problems and even business problems. These patterns are historically successful in solving very complex problems.

The ultimate goal is not to write code, not even building software, but to solve problems. Nobody wants your software; they want what it can give them.

Disadvantages

You will spend a lot of time talking about the domain and the problems that need to be solved. And you will spend plenty of time sorting out what is truly domain logic and what is just infrastructure.

DDD is not always the right path for your applications. And it’s helpful to keep in mind that exist some scenarios where DDD is an overkill. If you have an application or subdomain that is just a data-driven app and doesn’t do much more than a lot of crud logic, there is no needs to use DDD. It would be a waste of time and effort.

Technical complexity doesn’t mean business domain complexity. DDD may not just be a path because your project is technically challenging.

The Book

DDD was presented in 2003 by Eric Evans in a book titled Domain-Driven Design. The book was written for one major reason, and that is for solving complex problems. That’s why a subtitle of Evans's book is “Tackling Complexity in the Heart of Software”.

Summary

Domain-Driven Design helps man to understand women fully. No. I am joking. One book could not be enough.

What I want you to take with you is this. Be more chatty with your clients and always try to understand their needs. If you don’t understand each other, define your ubiquitous language.

Divide and conquer your business logic. Separation of Concerns, loose coupling, subdomains. So many titles for one thought. Divide your code into smaller pieces on every level.

Daniel Rusnok's Newsletter

Every month I will send you an email about with list of my newest articles. It will be ofcourse the friendly links…www.danielrusnok.com

If this resonated, you might also like The Claude Code Memory Starter — a short free email series, one bite-sized lesson at a time.

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