Book Image

The Definitive Guide to Modernizing Applications on Google Cloud

By : Steve (Satish) Sangapu, Dheeraj Panyam, Jason Marston
Book Image

The Definitive Guide to Modernizing Applications on Google Cloud

By: Steve (Satish) Sangapu, Dheeraj Panyam, Jason Marston

Overview of this book

Legacy applications, which comprise 75–80% of all enterprise applications, often end up being stuck in data centers. Modernizing these applications to make them cloud-native enables them to scale in a cloud environment without taking months or years to start seeing the benefits. This book will help software developers and solutions architects to modernize their applications on Google Cloud and transform them into cloud-native applications. This book helps you to build on your existing knowledge of enterprise application development and takes you on a journey through the six Rs: rehosting, replatforming, rearchitecting, repurchasing, retiring, and retaining. You'll learn how to modernize a legacy enterprise application on Google Cloud and build on existing assets and skills effectively. Taking an iterative and incremental approach to modernization, the book introduces the main services in Google Cloud in an easy-to-understand way that can be applied immediately to an application. By the end of this Google Cloud book, you'll have learned how to modernize a legacy enterprise application by exploring various interim architectures and tooling to develop a cloud-native microservices-based application.
Table of Contents (26 chapters)
1
Section 1: Cloud-Native Application Development and App Modernization in Google Cloud
5
Section 2: Selecting the Right Google Cloud Services
10
Section 3: Rehosting and Replatforming the Application
17
Section 4: Refactoring the Application on Cloud-Native/PaaS and Serverless in Google Cloud

Analyzing the structure of the application backend

In this section, we will be analyzing the packaging structure and dependencies of our application backend to decide what code refactoring is needed to restructure and repackage so that a microservice only contains the interfaces and classes it needs. It would be a rare application that can simply be repackaged without some code changes being necessary.

The dependency structure between the components of our application is shown in the following diagram:

Figure 13.1 – Component dependencies (legacy)

The preceding diagram shows the WAR file banking-rest, which as well as providing its own classes contains the JAR files for banking-domain, domain-driven-design, and firebase-authentication. The last two of those are supporting JAR files and not specific to any service, so each microservice will have a copy of domain-driven-design and firebase-authentication. Our target is to separate banking-rest and account...