Table Of ContentHands-On Microservices with
C# 8 and .NET Core 3
Third Edition
Refactor you monolith architecture into microservices using
Azure
Gaurav Aroraa
Ed Price
BIRMINGHAM - MUMBAI
Hands-On Microservices with C# 8 and
.NET Core 3
Third Edition
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To my younger sister, Preeti, who always inspires me with her positive attitude toward life.
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– Gaurav Aroraa
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Foreword
Microservices is more than just a buzzword. They represent a fresh new way of thinking
about systems architecture that builds upon the designs and layering of the last two
decades, combined with the real-world experiences of building large scalable systems at a
size we once thought impossible.
We've all learned about three-tiered architecture: we design our systems with the single
responsibility principle, and we have tried different ways to scale and deploy our systems.
Microservices combines the best of all these worlds. It aims to build systems that separate
responsibility appropriately; that manage, version, and deploy services individually; and
that elastically scale, backed by the power of the cloud.
This new generation of cloud-native applications needed a new way of thinking about
architecture. Gaurav and Ed have put together a journey that walks you through the
process of creating effective microservices, using C# 8 and the new open source, cross-
platform .NET Core.
The book covers everything that you'll need, from architecture, an introduction to
containers, and how services communicate, to the concepts behind a service mesh.
Everything is backed by practical examples in real-world use cases, including IoT.
I'm thrilled that you're coming along this journey with us, and I'm excited to see what you'll
be able to build with this new knowledge.
Scott Hanselman
Partner Program Manager
.NET Open Source
Contributors
About the authors
Gaurav Aroraa is a serial entrepreneur and start-up mentor. He has done an M.Phil in
computer science. He is a Microsoft MVP award recipient. He is a lifetime member of the
Computer Society of India (CSI), is an advisory member and senior mentor at IndiaMentor,
is certified as a Scrum trainer/coach, is ITIL-F certified, and is PRINCE-F and PRINCE-P
certified. He is an open source developer and a contributor to the Microsoft TechNet
community. Recently, Gaurav was awarded "Icon of the year – excellence in Mentoring
Technology Startups" for 2018-19 by Radio City, a Jagran initiative, for his extraordinary
work during his 22-year career in the industry in the field of technology mentoring.
In life, it's hard to understand things when you don't find support. My family is one such
support system and I am the luckiest to have them. I would like to thank my wife, Shuby
Aroraa, and my little angel, Aarchi Arora, who gave me permission to write and invest
time in this book.
A special thanks to the Packt team (especially Tiksha, Afshaan, and Richa) and Andreas
Helland. Also, a big thanks to Ed Price (my coauthor) and Scott Hanselman.
Ed Price is a senior program manager in engineering at Microsoft, with an MBA in
technology management. He has run Microsoft customer feedback programs for Azure
Development, Service Fabric, IoT, and Visual Studio. He was also a technical writer at
Microsoft for 6 years, helped to lead TechNet Wiki, and now leads efforts to publish key
guidance from AzureCAT (Customer Advisory Team), especially in the development of
microservices. He is the coauthor of Learn to Program with Small Basic.
About the reviewer
Andreas Helland has a degree in software engineering and over 20 years of experience in
building products and services. He has worked both with the development side and the
infrastructure side and holds a number of Microsoft certifications across various skill sets.
This also led him to become an early adopter of Azure. After building up his knowledge
working in the telecommunications industry, he switched to consulting, and currently
works as an architect for Capgemini where he assists customers on how to utilize the cloud
in the best ways possible. He specializes in Azure Active Directory and works closely with
the Identity teams at Microsoft, both in testing new services and providing feedback based
on learnings from the field.
I have to thank my family for allowing me to spend so much time "in my lab" working on
my pet projects as well as being more or less understanding of why a home needs proper IT
infrastructure. I've also been lucky with having employers that have given me great
freedom to work with the things I've wanted to and letting me "go crazy" with the
Microsoft tech stack. My output is certainly not a result purely based on what I put in.
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Table of Contents
Preface 1
Chapter 1: An Introduction to Microservices 7
Technical requirements 8
The origin of microservices 8
Discussing microservices 10
Exploring monolithic architecture 10
Service-oriented architecture 12
Understanding services 13
Understanding microservice architecture 16
Messaging in microservices 18
Synchronous messaging 18
Asynchronous messaging 19
Message formats 19
Using microservices 20
The workings of microservice architecture 20
The advantages of microservices 21
SOA versus microservices 22
The prerequisites of microservice architecture 23
Understanding the problems with the monolithic architectural style 24
The challenges in standardizing a .NET stack 25
Fault tolerance 26
The scaling property of a system 27
Vertical scaling or scale-up 27
Horizontal scaling or scale-out 28
Deployment challenges 28
Organizational alignment 29
Modularity 30
Big database 31
Prerequisites for microservices 31
Functional overview of the application 33
Solutions for the current challenges 34
Handling deployment problems 35
Making better monolithic applications 35
Introducing dependency injections 35
Database refactoring 40
Database sharding and partitioning 41
DevOps culture 43
Automation 43
Testing 43
Versioning 44
Deployment 44
Table of Contents
Identifying decomposition candidates within monolithic 45
Important microservices advantages 46
Technology independence 46
Interdependency removal 46
Alignment with business goals 47
Cost benefits 47
Easy scalability 47
Security 48
Data management 48
Integrating monolithic applications with microservices 49
An overview of Azure Service Fabric 50
Summary 52
Questions 52
Chapter 2: Refactoring the Monolith 53
Technical requirements 53
Understanding the current and new technology stack 54
Discussion – current stack (C#, EF, and SQL Server) 54
C# 8 54
Entity Framework Core 55
Visual Studio 2019 55
Microsoft SQL Server 55
New features in .NET Core 56
New features in C# 8.0 63
Enabling support for the C# 8.0 language using Visual Studio 63
Indices and ranges 65
The readonly members 69
Default interface methods 70
The size of microservices 71
What makes a good service? 72
DDD and its importance for microservices 73
Domain model design 73
Importance for microservices 74
Understanding the concept of seam 75
Module interdependency 75
Technology 76
Team structure 76
Databases 77
Master data 80
Transactions 81
Communication between microservices 82
The benefits of the API gateway for microservices 83
API gateway versus API management 84
Revisiting the FlixOne case study 84
Prerequisites 85
Transitioning to our product service 85
Migrations 87
[ ii ]
