Designing API-First Enterprise Architectures on Azure: A guide for architects and developers to expedite digital transformation with API-led architectures

BIRMINGHAM—MUMBAI

Designing API-First Enterprise Architectures on Azure

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To my mother, Krishna Chatterjee, and my father, the late Nirmalendu Chatterjee, whose countless sacrifices have made me the man that I am today.

To my elder brother, Abhijit, without whose support and guidance I wouldn't have come this far.

To my loving wife, Tamanna, for believing in me and keeping me motivated.

To my daughter, Tanusha, who makes me a proud father.

– Subhajit Chatterjee

Contributors

About the author

Subhajit Chatterjee completed his bachelor's degree in engineering from NITK, Surathkal, India, way back in 2002. He also holds a postgraduate diploma in information technology from Amity University. Aside from this, he has undertaken various other online certifications that have helped him to learn and grow as a software engineering professional.

Subhajit has close to two decades of exposure to designing, implementing, and managing software development projects, using Microsoft and open source technologies. He currently works as a solutions architect with Microsoft Consulting Services, leading large and complex projects in Azure, IoT, enterprise integrations, web applications, and mobility space.

Subhajit loves to solve problems and has had the privilege of working with customers across the globe. He is passionate about sharing what he learns with the community. He believes in continuous learning and enjoys coaching and mentoring others for professional enrichment.

I wish to thank the people who have been close to me and supported me, especially all my colleagues and mentors who have shared their knowledge and experiential learning with me.

About the reviewer

Niloshima Srivastava has around 12 years of experience working as Software Architect in a Product Based Organization. She is a graduate in CSE and holds several Cloud Certifications on Azure/AWS. She has been an evangelist when it comes to Microsoft platforms, augmented by being a hands-on developer, solution architect, and outstanding illustrator of design concepts and methodology. Not the least but proven track records even in training and orchestrating what she has learned to new rising developers across various platforms on various forums.

Table of Contents

Preface

Section 1: API-Led Architecture in the Digital Economy

Chapter 1: Evolution of Enterprise Solution Architectures

History of application architectures in an enterprise

From monoliths to SOA and microservices

IT strategies in the modern world

Outlook for digital transformation

The emergence of API-led architectures

The complexity problem

The importance of API-led architecture

Case study

About Packt Insurance Inc.

Summary

Further reading

Chapter 2: APIs as Digital Connectors

The connected enterprise

The role of APIs in digital experiences

Major benefits of API-led connectivity

APIs serve as digital enablers for an enterprise

An API is a digital service

API architecture within an enterprise

API classification by management and access pattern

Packt Insurance Inc. – an API-led architecture strategy

Domain decomposition

Service and persona map

API composability using microservices

Summary

Further reading

Section 2: Build Reliable API-Centric Solutions

Chapter 3: Architecture Principles and API Styles

Architecture principles

Evolve architecture blueprints iteratively

Constructs of an API

API operations or service contract

Data contract or entity schema

API endpoint

Communication protocol (application layer)

Input and output – the request-response pair

Popular API architecture styles

The tunneling or RPC style

RI (or REST) style

Query or GraphQL style

Event-driven or asynchronous messaging style

Hypermedia style

Other API styles

Finding the right style for your API use cases

Serverless APIs – accelerators for innovation

Benefits of using serverless computing for APIs

Serverless architecture use cases

Implementing API-led architectures in Azure

Reference architecture for an enterprise API platform

Azure services for hosting API solutions

Service Fabric

Additional services for building end-to-end solutions

Case study elaboration – Packt Insurance Inc.

API style fitment analysis

Microservices and API styles

API platform architecture

Summary

Additional reading

Chapter 4: Assuring the Quality of the API Service (or Product)

The ISO 25010 standard for software product quality

Functional Suitability

Operability/Usability

Reliability

Performance Efficiency

Security

Compatibility

Maintainability

Portability

Architecture Tradeoff Analysis Method (ATAM)

The Azure Well-Architected Framework

Benefits of using WAF

WAF recommended practices

API security considerations

Core principles – the Security Frame analysis

The Security Development Lifecycle (SDL)

Reliability through scale, performance, availability

Site Reliability Engineering (SRE)

How do you ensure appropriate reliability?

Commonly used SLOs for an API service

Defining, implementing, and measuring SLI metrics for an API platform

Using SLIs to calculate the initial SLOs for your API service

Modeling performance based on scale requirements

The API (or application) performance management lifecycle

Checklist for development teams

High-availability patterns

High-availability calculation

Architecting for operations

Logging, monitoring, and alerts

Feature flags

Understanding maintainability

Proactive maintainability

Reactive maintainability

Tracking objectives using a quality dashboard

Case study elaboration – Packt Insurance Inc.

Important SLOs for the API platform

Architecture backlog – focus on quality and handle technical debt

Summary

Further reading

Chapter 5: RESTful APIs – the New Web

Technical requirements

Understanding RESTful APIs

Using HTTP verbs for your CRUD actions correctly

History of inter-machine application communication

REST architecture constraints

Advantages and challenges of building a RESTful API

Advantages

Common challenges

Exploring the checklist for building RESTful APIs

Contract-first design for your REST APIs

OpenAPI Specification

OpenAPI definition file format

Visualizing the API definition file using the Swagger extension in VSCode           

Summary

Further reading

Chapter 6: API Design Practices

Understanding API design considerations

Coupling

Chattiness

Client complexity

Cognitive complexity

Caching

Discoverability

Versioning

Exploring recommended practices

Design should adhere to the SOLID principles

Design should be flexible to change

Use the Decision Analysis and Resolution technique

Produce documentation as per industry standards

Secure by design

Optimized for response time

API testing

Size and granularity

Content negotiation

Prefer stateless over stateful services

User-digestible response codes and messages

Using cloud design patterns

Implementing an API service using design patterns

Data-driven CRUD API

Command and Query Responsibility Segregation (CQRS)

Event Store API (Event Sourcing)

Clean architecture

Backends for Frontends (BFF)

Developer toolbox

Summary

Further reading

Chapter 7: Accelerating through DevOps Essentials

Business objectives and key results

The DevOps Dojo framework

The benefits of having a good DevOps strategy

DevOps metrics and their importance

Identifying the maturity index for your enterprise

The power of GitHub and Azure DevOps

DevOps in practice

Capability – continuous planning

Capability – continuous integration

Capability – continuous delivery

Capability – continuous operations

Capability – continuous quality

Capability – continuous security

Capability – continuous collaboration

Capability – continuous improvement

Pillar – culture

Pillar – lean product

Pillar – architecture

Pillar – technology

Tracking DevOps initiatives in the backlog

Summary

Further reading

Section 3: Deliver Business Value for a Modern Enterprise

Chapter 8: API-Centric Enterprise Integrations

Exploring EAI

Key initiatives toward a digital enterprise

Modernizing legacy applications using APIs

API use cases in the enterprise

The rise of iPaaS

What is an iPaaS platform?

Types of integrations

Benefits of iPaaS

iPaaS architecture for the Azure cloud

Implementing EAI patterns using iPaaS

API management

API gateways

API publishing, control, and governance

Developer portal

API versioning and life cycle management

Analytics and metrics

Understanding Azure Integration Services

iPaaS building blocks of Azure – explained

Using Azure Integration Services

Summary

Further reading

Chapter 9: APIs as a Monetized Product

APIs as digital assets

Growth of the API economy

The API value chain

Exploring business drivers of monetization

Expand the channels of revenue streams

Capture analytics for improved marketing strategies

Enhance brand value through customer loyalty

Foster innovation through new product capabilities

Stay relevant in the marketplace

API monetization models

Free

Consumer pays

Consumer gets paid

Indirect monetization

API productization in Azure

Requirements summary

Solution approach

API products and publishing in APIM

Subscription management

API consumption – rate limits and quotas

Measuring API consumption

API analytics

Summary

Further reading

Why subscribe?

Other Books You May Enjoy

Preface

Rapid adoption of cloud technologies has revolutionized the way modern-day applications are architected and implemented. Solution architects and IT decision-makers are constantly faced with the challenge to quickly adapt to the latest technology trends to establish a competitive advantage in the marketplace. Gartner has predicted that by 2025, about 80% of enterprises will have shifted their operations to the cloud. Hence, it has become even more imperative that enterprises pay attention to their digital transformation roadmaps to benefit from their cloud-first and mobile-first initiatives. Tactically, this means a lot of changes on the ground, including reinventing business processes, adopting agile and DevOps best practices, and even embarking on the modernization of operations.

API-led architecture is not something new – rather, it has just become a lot more relevant and important in today's world. Cloud computing offers three key benefits: flexibility, efficiency, and strategic value. API-led connectivity has changed the way enterprises interact with their customers and partners. Customers today are very demanding. They expect businesses to be agile and adapt to their demands. They prefer a simple and intuitive approach to meeting their needs. They are open to the use of technology and apps to get the job done in just a few steps. Thus, enterprises are required to utilize the insights derived from analyzing customer behavior as the basis for their digital innovation strategies.

Over the past few years, I have worked with multiple enterprise customers to define their blueprints for a robust and reliable API-led solution. However, the common challenge has been in getting them to understand the benefits of this approach, as it requires some initial investment and work prioritization. It was always a hard sell unless the key stakeholders had prior experience with implementing solutions using a service-oriented architecture (SOA) approach. Many lacked the appetite to incur any additional complexity on top of what they were used to. It was also a revelation to me that teams weren't too well versed in the concept of microservices. Everybody wanted to do it, but nobody seemed to know how to approach it. A few believed that splitting a large monolith into smaller services was, in effect, building microservices. While this was still a good starting point, it lacked a futuristic vision, as the many other aspects of a microservices architecture were not considered as part of the design process. The technical teams were also getting used to the new way of building solutions and would often miss out on the fundamentals, leading to problems later in the life cycle. Teams often lacked a production-first mindset as many of the important architecture-critical requirements were deferred to later.

In this book, it has been my endeavor to provide a glimpse of the whole nine yards that is essential for the successful delivery of an API-led enterprise solution. This book focuses on the latest emerging trends in the industry, supplementing theoretical concepts with real-world scenarios and examples to help you grasp the concepts more easily. The book touches upon the important principles and practices that can eventually serve as a checklist for development teams. While I have used the Microsoft Azure cloud as the platform of choice, the topics discussed are valid even for a multi-cloud scenario as well.

After reading this book, you will be well versed in how to architect, design, implement, deploy, and maintain a digital service.

Who this book is for

This book is meant to serve as a ready reckoner for solution architects, developers, and IT and business decision-makers as they are taken through a journey showing how to approach their API-led connectivity requirements. The book has been written from a practitioner's point of view, with lots of tips, practical guidance, and additional references that will surely provide clarity of thought for developers, allowing them to confidently prepare for their next API-first architecture implementation.

What this book covers

Chapter 1, Evolution of Enterprise Solution Architectures, gives you a background on the evolution of enterprise architectures, from SOA to a more microservices-based approach, and discusses how the adoption of open standards will help advance the building of interconnected experiences in the evolution process.

Chapter 2, APIs as Digital Connectors, walks you through the concept of a connected enterprise, emphasizing the role and importance of APIs in fueling the growth of the digital economy.

Chapter 3, Architecture Principles and API Styles, provides an overview of important architecture principles that are the basis for the foundation of any API platform. The chapter also covers the popular architecture styles that are frequently used in an enterprise and how they can be implemented in the Azure cloud.

Chapter 4, Assuring the Quality of the API Service (or Product), focuses on the quality attributes that are critical for the success of API solutions. It also explains how to make use of the Azure Well-Architected Framework to design, implement, and measure the quality of service for your API solutions.

Chapter 5, RESTful APIs – The New Web Standard, covers some of the best practices that must be followed while designing and implementing RESTful-style API interfaces, which are becoming a new web standard.

Chapter 6, API Design Practices, discusses the important design practices that must be followed while building your API-centric solutions. It also briefly covers the different patterns that are commonly used for implementing your API microservices.

Chapter 7, Accelerating through DevOps Essentials, focuses on the essential DevOps practices that must be followed by the engineering teams to drive greater IT maturity across the broad spectrum of the enterprise.

Chapter 8, API-Centric Enterprise Integrations, takes a deeper look into some real-world enterprise integration scenarios and considers how the Azure Integration Services offering can be utilized for this purpose.

Chapter 9, API as a Monetized Product, discusses how enterprises can realize greater business value and improve their revenue streams by applying an intelligent productization strategy for their API assets.

To get the most out of this book

This book is intended for audiences who are likely to have a role in either defining and/or implementing API-centric solutions. Hence, it is recommended that you apply the inferences shared to your own practical requirements and do further self-study and analysis to better understand the concepts presented.

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://static.packt-cdn.com/downloads/9781801813914_ColorImages.pdf.

Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: For example, say the URI /api/policies/id returned the policy resource for the specified ID. Then the URL /api/policies/id/assets will return all the assets linked to the respective policy.

A block of code is set as follows:

GET /policy/getPolicy?id=POLICY1122334455 HTTP/1.1

Host: api.contoso.inc

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

https://api.packinsurance.com/quotingservice/getquote?api-version=1.0

https://api.packinsurance.com/quotingservice/getquote?api-version=2.0

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: Observe that Quote Service (Basic) is accessible to Guests.

Tips or important notes

Appear like this.

Get in touch

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Section 1: API-Led Architecture in the Digital Economy

In the first part of the book, you will discover why API-based integration architectures within enterprises are increasing, and how they are beneficial compared to traditional approaches to expedite digital transformation in a cloud-first, mobile-first world.

This section includes the following chapters:

Chapter 1, Evolution of Enterprise Solution Architectures

Chapter 2, APIs as Digital