Table Of Contentwith examples in Nancy
Christian Horsdal Gammelgaard
M A N N I N G
What is a microservice?
In short, a microservice is a very narrowly focused service
that has the following characteristics:
A microservice is responsible for a single piece of func-
tionality.
A microservice is individually deployable.
A microservice consists of one or more processes.
A microservice owns its own data store.
A small team can maintain a handful of microservices.
A microservice is replaceable.
You can use these characteristics in two ways: to guide the
design and implementation of microservices, and to recog-
nize microservices when you see them.
Microservices in .NET Core
Microservices in .NET Core
WITH EXAMPLES IN NANCY
CHRISTIAN HORSDAL GAMMELGAARD
MANNING
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brief contents
PART 1 GETTING STARTED WITH MICROSERVICES.......................1
1 ■ Microservices at a glance 3
2 ■ A basic shopping cart microservice 30
PART 2 BUILDING MICROSERVICES...........................................55
3 ■ Identifying and scoping microservices 57
4 ■ Microservice collaboration 79
5 ■ Data ownership and data storage 109
6 ■ Designing for robustness 134
7 ■ Writing tests for microservices 155
PART 3 HANDLING CROSS-CUTTING CONCERNS: BUILDING
A REUSABLE MICROSERVICE PLATFORM ......................183
8 ■ Introducing OWIN: writing and testing OWIN
middleware 185
9 ■ Cross-cutting concerns: monitoring and logging 199
v
vi BRIEF CONTENTS
10 ■ Securing microservice-to-microservice
communication 223
11 ■ Building a reusable microservice platform 248
PART 4 BUILDING APPLICATIONS ...........................................271
12 ■ Creating applications over microservices 273
contents
preface xiii
acknowledgments xiv
about this book xv
about the cover illustration xix
PART 1 GETTING STARTED WITH MICROSERVICES..............1
1 Microservices at a glance 3
1.1 What is a microservice? 3
What is a microservices architecture? 5 ■ Microservice characteristics 5
1.2 Why microservices? 10
Enabling continuous delivery 11 ■ High level of
maintainability 12 ■ Robust and scalable 13
1.3 Costs and downsides of microservices 13
1.4 Greenfield vs. brownfield 14
1.5 Code reuse 15
1.6 Serving a user request: an example of how microservices work
in concert 16
Main handling of the user request 17 ■ Side effects of the user
request 18 ■ The complete picture 19
vii
viii CONTENTS
1.7 A .NET microservices technology stack 20
Nancy 20 ■ OWIN 21 ■ Setting up a development
environment 22
1.8 A simple microservices example 23
Creating an empty ASP.NET Core application 24 ■ Adding
Nancy to the project 24 ■ Adding a Nancy module with an
implementation of the endpoint 25 ■ Adding OWIN
middleware 27
1.9 Summary 28
2 A basic shopping cart microservice 30
2.1 Overview of the Shopping Cart microservice 31
Components of the Shopping Cart microservice 33
2.2 Implementing the Shopping Cart microservice 34
Creating an empty project 34 ■ The Shopping Cart microservice’s
API for other services 35 ■ Fetching product information 42
Parsing the product response 44 ■ Adding a failure-handling
policy 46 ■ Implementing a basic event feed 48
2.3 Running the code 52
2.4 Summary 52
PART 2 BUILDING MICROSERVICES..................................55
3 Identifying and scoping microservices 57
3.1 The primary driver for scoping microservices:
business capabilities 58
What is a business capability? 58 ■ Identifying business
capabilities 59 ■ Example: point-of-sale system 60
3.2 The secondary driver for scoping microservices: supporting
technical capabilities 65
What is a technical capability? 65 ■ Examples of supporting
technical capabilities 65 ■ Identifying technical capabilities 69
3.3 What to do when the correct scope isn’t clear 69
Starting a bit bigger 70 ■ Carving out new microservices from
existing microservices 73 ■ Planning to carve out new
microservices later 75
