Go Lang in Depth Guide to program microservices, networking, database and APIs using Go Lang (Bhagvan Kommadi) (Z-Library)

Go Lang in Depth Guide to program microservices, networking, database and APIs using Go Lang Bhagvan Kommadi

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First Edition 2025 Copyright © BPB Publications, India ISBN: 978-93-65894-806 All Rights Reserved. No part of this publication may be reproduced, distributed or transmitted in any form or by any means or stored in a database or retrieval system, without the prior written permission of the publisher with the exception to the program listings which may be entered, stored and executed in a computer system, but they can not be reproduced by the means of publication, photocopy, recording, or by any electronic and mechanical means. LIMITS OF LIABILITY AND DISCLAIMER OF WARRANTY The information contained in this book is true to correct and the best of author’s and publisher’s knowledge. The author has made every effort to ensure the accuracy of these publications, but publisher cannot be held responsible for any loss or damage arising from any information in this book. All trademarks referred to in the book are acknowledged as properties of their respective owners but BPB Publications cannot guarantee the accuracy of this information. www.bpbonline.com

Dedicated to My dad who passed away during this book writing and My mom my strength and support system

About the Author Bhagvan Kommadi has around 21 years of experience and is currently working as a chief information officer. He is responsible for creating and managing the company's IT strategy, operations, and resources. He is responsible for the alignment of the company’s goals and objectives with IT strategy and operations. He ensures that the IT performance operates at high productivity and delivers high business value to the customers and employees. He establishes policies and the best practices in the company, using the right IT governance to meet compliance requirements. He is responsible for ensuring IT infrastructure’s data quality, integrity, and security standards. He has a Master’s in Industrial Systems Engineering from the Georgia Institute of Technology (1997) and a Bachelor’s in Aerospace Engineering from the Indian Institute of Technology, Madras (1993). He is an individual member of Oracle JCP. He has published papers on IEEE, JIMR, Johr Online, and the Association of Data Scientists (ADaSci) on the latest technologies. He is a TEDx Speaker and has presented at EuroPython, Pycon, ClueCon Weekly, World RPA Conference, and Avios conferences. He has written Packt Publishing - Hands-On Data Structures and Algorithms with Go and Paytech book on The Payment Technology Handbook for Investors, Entrepreneurs, and FinTech Visionaries He has worked extensively in FinTech Space in various verticals such as banking, financial services, and insurance.

Bhagvan has worked for Fortune 500 companies, including JPMC, Fidelity, Oracle, Siebel, Citi, American Express, ING, ENBD, Pacific Corp, and Kaiser Permanente. He has provided technology and business process reengineering consulting guidance and implemented various new-generation platforms for business enablement. Bhagvan founded Quantica Computacao, the first quantum computing startup in India. Markets and Markets has positioned Quantica Computacao in the ‘Emerging Companies’ section of Quantum Computing quadrants. The company's focus is on developing quantum cryptographic tools that will be able to provide quantum-proof data security, which will help banking institutions protect their transactions. He contributes to open-source projects, blogs, and the latest technology stacks such as Go, Python, Django, Node.js and Java, Mysql, Postgres, Mongo, and Cassandra. He has reviewed the Manning book Machine Learning with TensorFlow. He has written Data Structures and Algorithms with Golang (Packt) and Quantum Computing Solutions (Apress). He has presented at IEEE, Avios, Astricon, Devcon, and PyCon on topics such as Adaptive Learning and AI Coder.

About the Reviewer Mahima Singla is a passionate Principal Software Design Engineer with extensive professional experience and passion for designing and implementing robust, scalable software solutions in the domain of Cloud Assessment, Cloud Governance, Cloud Cost Optimization, Application fitment for cloud, Cloud Operating Models, cutting-edge technologies, particularly in the realms of Cloud computing, AWS, and Kubernetes in Go language. She is currently working in Precisely Software and is part of the Studio Administrator Cloud project and Customer Onboarding project. She has played a pivotal role in architecting and developing solutions that harness the full potential of cloud platforms. She has proficiency in AWS, including services like AWS services EC2, S3, and Lambda, has allowed her to create resilient and scalable applications that align with business objectives. Additionally, proficiency in Kubernetes reflects the commitment to staying at the forefront of container orchestration. She has successfully implemented and managed containerized workloads, ensuring efficiently managed containerized workloads, efficient resource utilization, and high availability for applications. Throughout her career, she has not only focused on technical excellence but also on driving innovation and fostering collaborative environments. As a Principal Software Engineer, she takes pride in leading teams to deliver high- quality solutions that meet and exceed client expectations.

She is dedicated to staying abreast of industry trends and leveraging the latest technologies has allowed her to contribute meaningfully to the success of the projects she undertakes. She is quite excited about the continuous evolution of software engineering and is always eager to take on new challenges that push the boundaries of what is possible in the world of cloud-native development.

Acknowledgement Embarking on the journey of writing Go Lang in Depth has been wonderful, and I am deeply grateful to the BPB team, who have played a crucial role in bringing this book to fruition. This endeavor would not have been possible without the unwavering support, guidance, and expertise generously provided by my parents and kids. To my parents and kids, thank you for your unwavering support. In the middle of this book journey, my father passed away. I dedicate this book to his support and guidance during this book journey. I want to express deep appreciation to my mom, whose encouragement and understanding have been a constant source of strength throughout this writing journey. Firstly, my heartfelt thanks go to the Go Lang community, whose dedication to the framework has shaped this book. Special gratitude is extended to the technical reviewers whose meticulous reviews and insightful feedback enhanced the book. Their dedication and expertise have been invaluable in refining the content and ensuring its accuracy. To all those at the BPB Publications house who have contributed in various capacities, your collective efforts have enriched this endeavor. I appreciate the collaborative spirit that has fueled the creation of Go Lang in Depth. Finally, to the readers, thank you for choosing this book as your source of knowledge. May it be a valuable companion on your journey to learning Go Lang in Depth.

Preface Understanding the basics of digital systems and technology is important in today's rapidly evolving world. This book, Go Lang in Depth, covers the essential concepts that form the backbone of digital systems. In the fast-evolving landscape of Go Lang development, understanding the development of apps using Go Lang is very important for aspiring developers. There are many open-source, popular frameworks in Go Lang. New open- source frameworks have embraced Go Lang as the language for their tech stack. This book comprises 17 chapters, each a complete module in itself, serving as your comprehensive guide to learning Go Lang in Depth. It covers a wide array of topics, ranging from the fundamentals to advanced techniques. Whether you're a seasoned developer looking to expand your skills or a newcomer eager to dive into Go Lang development, this book has something for everyone. Through practical examples, comprehensive explanations, and a structured approach, this book aims to equip readers with a solid understanding of Go Lang programming and software engineering. Whether you are a novice or an experienced learner, I hope this book will serve as a valuable resource in your journey of exploring the foundations of digital systems and technology. Chapter 1: Go Fundamentals - In this chapter, readers will be presented with fundamentals in Go language. The

topics like data types, variables, constants, operators, and Go programming will be discussed. Chapter 2: Advanced Features of Go - In this chapter, readers will be presented with advanced features like error handling, interfaces, typecasting, concurrency, and Mutex. These topics will be discussed with coding examples. Chapter 3: Go Console Applications - In this chapter, readers will be presented with techniques to build console- based applications. Applications will have the capability to read input and write output. The input and the output can be of different formats like CSV, properties, XML, and JSON. Console applications can talk to a database, and these apps will be built in Go. Data structures in Go will be discussed. Chapter 4: Building Rest API - In this chapter, readers will learn about different algorithms which can be implemented in Go. They will also know how to develop REST API to access data from different data sources. The REST API can read and write data to data sources like relational databases, no sql databases, and message queues. REST API clients can be web applications and mobile applications Chapter 5: Go Web Apps - In this chapter, readers will be presented with examples and solutions to build web applications using Gin and Beego. Web applications will consume REST API and communicate to databases through the API. These web applications will be built to be scalable and performable. Chapter 6: RPC Apps with gRPC - In this chapter, the reader can build RPC apps using Go. These apps are built using Google gRPC. Readers will know about Protocol Buffers. gRPC clients will be developed to talk to the gRPC server. Unit tests will be written to test the clients and server code.

Chapter 7: Go Real Life Applications - CRM- In this chapter, readers will learn how to build a real-life application of customer relationship management. CRM application will be a web application that will have the capability to maintain customer data and run campaigns for segments or a list of customers by geography or vertical. Chapter 8: Go Concurrent Apps- In this chapter, readers will learn how to build concurrent applications using Go. Readers will know how to use goroutines, channels, and concurrency using Go. The reader will understand the principles of concurrency and parallelism. Chapter 9: Go Dependency Injection and SOLID - In this Chapter, the Reader will understand dependency injection using the Go Language. The reader will also understand SOLID principles, which include dependency inversion. The reader will also learn different types of dependency injection, such as constructor, property, and method. Chapter 10: Containerization and Docker - In this chapter, the reader will understand containers and Docker. The reader will be able to develop services that can be containerized using Docker. Docker images can be created and posted on the Docker Hub for different Go services. Chapter 11: Go Microservices - In this chapter, the reader will understand the principles of microservices architecture vs. monolithic architecture. The reader will be able to create an architecture using Microservices and deploy these services on the containers. Chapter 12: Adding Security and IAM - In this chapter, readers will learn how to build security services like authentication, authorization, encryption, and identity management. Readers will learn about Cross-Site Request Forgery (CSRF) prevention middleware. Readers can

understand the security principles to build scalable and secure web applications. Chapter 13: Go Design Patterns–Part 1 - In this chapter, readers can understand different design patterns like Creational and Structural Design patterns. Code samples will be provided for the Gang of Four Design patterns. Readers will understand object-oriented design principles using Go Chapter 14: Go Design Patterns–Part 2 - In this chapter, readers can understand different design patterns, like Behavioral Design patterns. And Object-oriented Design Patterns. Code samples will be provided for the Gang of Four Design patterns and Object-oriented Design Patterns. Readers will understand object-oriented design principles using Go. Chapter 15: Go Performance Tuning Patterns - In this chapter, the reader will learn how to develop responsive and performant Go applications. Different performance tuning and optimization patterns are presented with code samples, and the reader will understand these techniques while building web applications. Chapter 16: Web Web App Blueprints - In this chapter, readers will be presented with web app blueprint applications. Readers will understand the design and architecture principles to build scalable web applications. The blueprint solutions will have tips and techniques to build responsive web applications that are performant. Chapter 17: Go Mobile Applications Blueprints - In this chapter, readers will be presented with mobile app blueprint applications. Readers will understand the design and architecture principles to build scalable mobile applications. The blueprint solutions will have tips and techniques for building performant mobile applications.

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Table of Contents 1. Go Fundamentals Introduction Structure Objectives Basic programming in Go Data types Basic types Composite types Reference types Interface types Variables Constants Operators Conditional statements if condition statement Switch statement Strings and arrays Strings Arrays Maps Pointers and structures Pointers Structures

Recover, defer, and panic Conclusion Points to remember 2. Advanced Features of Go Introduction Structure Objectives Error handling Interfaces Empty interface Type assertion Type switch Zero value of interface Type casting Concurrency Mutex Conclusion Points to remember 3. Go Console Applications Introduction Structure Objectives Console-based app in Go language Different input and output formats Text format JSON XML