Welcome!

Microservices Expo Authors: AppNeta Blog, Jason Bloomberg, Elizabeth White, Gopala Krishna Behara, Sridhar Chalasani

Blog Feed Post

Implementing Domain-Driven Design Book Review

Agile is not easy and implementing Domain-Driven Design (DDD) is not easy. I think my favorite part of the book is that the author realizes that, and also has a realistic perspective on what it takes to successfully use agile processes and DDD.

The book starts out with a really nice overview of DDD. By the time you are done the first chapter you have a pretty good high level picture of what DDD is all about. One topic he really drives home is Ubiquitous Language.

Ubiquitous Language is a shared team language that defines a certain domain. When you are reading about Ubiquitous Language it may seem like something that just happens on its own. It isn't. An explicit domain language should be defined, it should not just be allowed to implicitly come about. This same concept has been around for years in Water Fall, Unified Process, RUP, and other processes. It has always been a very important part of the software development process, so don't discount it.

Chapter 1 also does a great job of providing tips on how to show the business value of using DDD. The author has a clear understanding that without the support of the business you aren't going to get very far with your project, and in order to get them onboard you need to show them what they will gain by supporting DDD.

The remaining chapters dig into the details of DDD. I have listed the chapters below. Their titles are pretty self-explanatory.

Chapter 1. Getting Started with DDD
Chapter 2. Domains, Subdomains, and Bounded Contexts
Chapter 3. Context Maps
Chapter 4. Architecture
Chapter 5. Entities
Chapter 6. Value Objects
Chapter 7. Services
Chapter 8. Domain Events
Chapter 9. Modules
Chapter 10. Aggregates
Chapter 11. Factories
Chapter 12. Repositories
Chapter 13. Integrating Bounded Contexts
Chapter 14. Application
Appendix A. Aggregates and Event Sourcing: A+ES

I have seen a lot of teams that could not build software with UP or RUP adopt Scrum in hopes that changing the process will make a difference. It never does. There are a variety of reasons including not doing any architecture, not having experienced developers with the right skill sets, not having the right business users involved, not having the requirements elicitation skills needed, and the list can go on and on. The author clearly understands Scrum is not a silver bullet. I mention this because DDD done correctly can give agile processes a much better chance at success, but you must have the skills on the team in order pull it off.

I was really glad to see the author included a chapter on architecture. The author does a great job of covering a ton of architectural styles and patterns. Patterns, styles, and topic found in the Architecture chapter include Layers Architecture with the Dependency Inversion Principle, Hexagonal Architecture, SOA environment, REST, Data Fabric, Grid-Based Distributed Cache, and CQRS.

Every chapter is an in depth look at the topic of the given chapter. I did not leave any of the chapters feeling like I missed something. I have read both Domain-Driven Design: Tackling Complexity in the Heart of Software and Patterns of Enterprise Application Architecture, and I had both handy for looking up references to them. It is not necessary to read them first, but it did help that I had.

I am not going to say using DDD is easy, but I will say this book can definitely get you to where you can successfully use it. The author's writing style is really good and he is good at making the book entertaining. I will however say this, be prepared to read the entire book if you want to get to that point of successfully using DDD. There is a lot to learn, but it is worth it.

I highly recommend this book to every software architect and developer. Even if you don't go all out DDD there is a ton of great advice and wisdom found in this book that will help you improve your skills.

Implementing Domain-Driven Design

Read the original blog entry...

More Stories By Tad Anderson

Tad Anderson has been doing Software Architecture for 18 years and Enterprise Architecture for the past few.

@MicroservicesExpo Stories
The IT industry is undergoing a significant evolution to keep up with cloud application demand. We see this happening as a mindset shift, from traditional IT teams to more well-rounded, cloud-focused job roles. The IT industry has become so cloud-minded that Gartner predicts that by 2020, this cloud shift will impact more than $1 trillion of global IT spending. This shift, however, has left some IT professionals feeling a little anxious about what lies ahead. The good news is that cloud computin...
By now, every company in the world is on the lookout for the digital disruption that will threaten their existence. In study after study, executives believe that technology has either already disrupted their industry, is in the process of disrupting it or will disrupt it in the near future. As a result, every organization is taking steps to prepare for or mitigate unforeseen disruptions. Yet in almost every industry, the disruption trend continues unabated.
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In his Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, will explore t...
As Enterprise business moves from Monoliths to Microservices, adoption and successful implementations of Microservices become more evident. The goal of Microservices is to improve software delivery speed and increase system safety as scale increases. Documenting hurdles and problems for the use of Microservices will help consultants, architects and specialists to avoid repeating the same mistakes and learn how and when to use (or not use) Microservices at the enterprise level. The circumstance w...
Lots of cloud technology predictions and analysis are still dealing with future spending and planning, but there are plenty of real-world cloud use cases and implementations happening now. One approach, taken by stalwart GE, is to use SaaS applications for non-differentiated uses. For them, that means moving functions like HR, finance, taxes and scheduling to SaaS, while spending their software development time and resources on the core apps that make GE better, such as inventory, planning and s...
Everyone wants to use containers, but monitoring containers is hard. New ephemeral architecture introduces new challenges in how monitoring tools need to monitor and visualize containers, so your team can make sense of everything. In his session at @DevOpsSummit, David Gildeh, co-founder and CEO of Outlyer, will go through the challenges and show there is light at the end of the tunnel if you use the right tools and understand what you need to be monitoring to successfully use containers in your...
What if you could build a web application that could support true web-scale traffic without having to ever provision or manage a single server? Sounds magical, and it is! In his session at 20th Cloud Expo, Chris Munns, Senior Developer Advocate for Serverless Applications at Amazon Web Services, will show how to build a serverless website that scales automatically using services like AWS Lambda, Amazon API Gateway, and Amazon S3. We will review several frameworks that can help you build serverle...
The Software Defined Data Center (SDDC), which enables organizations to seamlessly run in a hybrid cloud model (public + private cloud), is here to stay. IDC estimates that the software-defined networking market will be valued at $3.7 billion by 2016. Security is a key component and benefit of the SDDC, and offers an opportunity to build security 'from the ground up' and weave it into the environment from day one. In his session at 16th Cloud Expo, Reuven Harrison, CTO and Co-Founder of Tufin, ...
SYS-CON Events announced today that HTBase will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...
Building custom add-ons does not need to be limited to the ideas you see on a marketplace. In his session at 20th Cloud Expo, Sukhbir Dhillon, CEO and founder of Addteq, will go over some adventures they faced in developing integrations using Atlassian SDK and other technologies/platforms and how it has enabled development teams to experiment with newer paradigms like Serverless and newer features of Atlassian SDKs. In this presentation, you will be taken on a journey of Add-On and Integration ...
Culture is the most important ingredient of DevOps. The challenge for most organizations is defining and communicating a vision of beneficial DevOps culture for their organizations, and then facilitating the changes needed to achieve that. Often this comes down to an ability to provide true leadership. As a CIO, are your direct reports IT managers or are they IT leaders? The hard truth is that many IT managers have risen through the ranks based on their technical skills, not their leadership abi...
The essence of cloud computing is that all consumable IT resources are delivered as services. In his session at 15th Cloud Expo, Yung Chou, Technology Evangelist at Microsoft, demonstrated the concepts and implementations of two important cloud computing deliveries: Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). He discussed from business and technical viewpoints what exactly they are, why we care, how they are different and in what ways, and the strategies for IT to transi...
Without a clear strategy for cost control and an architecture designed with cloud services in mind, costs and operational performance can quickly get out of control. To avoid multiple architectural redesigns requires extensive thought and planning. Boundary (now part of BMC) launched a new public-facing multi-tenant high resolution monitoring service on Amazon AWS two years ago, facing challenges and learning best practices in the early days of the new service.
All organizations that did not originate this moment have a pre-existing culture as well as legacy technology and processes that can be more or less amenable to DevOps implementation. That organizational culture is influenced by the personalities and management styles of Executive Management, the wider culture in which the organization is situated, and the personalities of key team members at all levels of the organization. This culture and entrenched interests usually throw a wrench in the work...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
As software becomes more and more complex, we, as software developers, have been splitting up our code into smaller and smaller components. This is also true for the environment in which we run our code: going from bare metal, to VMs to the modern-day Cloud Native world of containers, schedulers and micro services. While we have figured out how to run containerized applications in the cloud using schedulers, we've yet to come up with a good solution to bridge the gap between getting your contain...
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningf...
DevOps has often been described in terms of CAMS: Culture, Automation, Measuring, Sharing. While we’ve seen a lot of focus on the “A” and even on the “M”, there are very few examples of why the “C" is equally important in the DevOps equation. In her session at @DevOps Summit, Lori MacVittie, of F5 Networks, explored HTTP/1 and HTTP/2 along with Microservices to illustrate why a collaborative culture between Dev, Ops, and the Network is critical to ensuring success.
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
An overall theme of Cloud computing and the specific practices within it is fundamentally one of automation. The core value of technology is to continually automate low level procedures to free up people to work on more value add activities, ultimately leading to the utopian goal of full Autonomic Computing. For example a great way to define your plan for DevOps tool chain adoption is through this lens. In this TechTarget article they outline a simple maturity model for planning this.