The Go Workshop : Learn to Write Clean, Efficient Code and Build High-performance Applications with Go

Cut through the noise and get real results with a step-by-step approach to learning Go programming Key Features Ideal for the Go beginner who is getting started for the first time A step-by-step Go tutorial with exercises and activities that help build key skills Structured to let you progress at your own pace, on your own terms Use your physical print copy to redeem free access to the online interactive edition Book Description You already know you want to learn Go, and the smart way to learn anything is to learn by doing. The Go Workshop focuses on building up your practical skills so that you can develop high-performing concurrent applications, or even create Go scripts to automate repetitive daily tasks. You'll learn from real examples that lead to real results. Throughout The Go Workshop, you'll take an engaging step-by-step approach to understanding Go. You won't have to sit through any unnecessary theory. If you're short on time you can jump into a single exercise each day, or you can spend an entire weekend learning how to test and secure your Go applications. It's your choice. Learning on your terms, you'll build up and reinforce key skills in a way that feels rewarding. Every physical print copy of The Go Workshop unlocks access to the interactive edition. With videos detailing all exercises and activities, you'll always have a guided solution. You can also benchmark yourself against assessments, track your progress, and receive content updates. You'll even earn secure credentials that you can share and verify online upon completion. It's a premium learning experience that's included with your printed copy. To redeem it, follow the instructions located at the start of your Go book. Fast-paced and direct, The Go Workshop is the ideal companion for Go beginners. You'll build and iterate on your code like a software developer, learning along the way. This process means that you'll find that your new skills stick, embedded as best practice. A solid foundation for the years ahead. What you will learn Get to grips with Go fundamentals and best practices Learn how to effectively organize your code for production environments Explore how third-party packages can help make you a better engineer Keep your development process bug-free with unit tests and benchmarks Who this book is for Our goal at Packt is to help you be successful, in whatever it is you choose to do. The Go Workshop is an ideal Go tutorial for the Go beginner who is just getti.. Cover FM Copyright Table of Contents Preface Chapter 1: Variables and Operators Introduction What Does Go Look Like? Exercise 1.01: Using Variables, Packages, and Functions to Print Stars Activity 1.01 Defining and Printing Declaring Variables Declaring a Variable Using var Exercise 1.02: Declaring a Variable Using var Declaring Multiple Variables at Once with var Exercise 1.03: Declaring Multiple Variables at Once with var Skipping the Type or Value When Declaring Variables Exercise 1.04: Skipping the Type or Value When Declaring Variables Type Inference Gone Wrong Short Variable Declaration Exercise 1.05: Implementing Short Variable Declaration Declaring Multiple Variables with a Short Variable Declaration Exercise 1.06: Declaring Multiple Variables from a Function Using var to Declare Multiple Variables in One Line Non-English Variable Names Changing the Value of a Variable Exercise 1.07: Changing the Value of a Variable Changing Multiple Values at Once Exercise 1.08: Changing Multiple Values at Once Operators Exercise 1.09 Using Operators with Numbers Shorthand Operator Exercise 1.10: Implementing Shorthand Operators Comparing Values Exercise 1.11: Comparing Values Zero Values Exercise 1.12 Zero Values Value versus Pointer Getting a Pointer Exercise 1.13: Getting a Pointer Getting a Value from a Pointer Exercise 1.14: Getting a Value from a Pointer Function Design with Pointers Exercise 1.15: Function Design with Pointers Activity 1.02: Pointer Value Swap Constants Exercise 1.16: Constants Enums Scope Activity 1.03: Message Bug Activity 1.04: Bad Count Bug Summary Chapter 2: Logic and Loops Introduction if Statements Exercise 2.01: A Simple if Statement if else Statements Exercise 2.02: Using an if else Statement else if Statements Exercise 2.03: Using an else if Statement The Initial if Statement Exercise 2.04: Implementing the Initial if Statements Activity 2.01: Implementing FizzBuzz Expression switch Statements Exercise 2.05: Using a switch Statement Exercise 2.06: switch Statements and Multiple case Values Exercise 2.07: Expressionless switch Statements Loops Exercise 2.08: Using the for i Loop Exercise 2.09: Looping Over Arrays and Slices The range Loop Exercise 2.10: Looping Over a Map Activity 2.02: Looping Over Map Data Using range break and continue Exercise 2.11: Using break and continue to Control Loops Activity 2.03: Bubble Sort Summary Chapter 3: Core Types Introduction True and False Exercise 3.01: Program to Measure Password Complexity Numbers Integer Floating Point Exercise 3.02: Floating-Point Number Accuracy Overflow and Wraparound Exercise 3.03: Triggering Number Wraparound Big Numbers Exercise 3.04: Big Numbers Byte Text Rune Exercise 3.05: Safely Looping over a String The nil Value Activity 3.01: Sales Tax Calculator Activity 3.02: Loan Calculator Summary Chapter 4: Complex Types Introduction Collection Types Arrays Exercise 4.01: Defining an Array Comparing Arrays Exercise 4.02: Comparing Arrays Initializing Arrays Using Keys Exercise 4.03: Initializing an Array Using Keys Reading from an Array Exercise 4.04: Reading a Single Item from an Array Writing to an Array Exercise 4.05: Writing to an Array Looping an Array Exercise 4.06: Looping Over an Array Using a "for i" Loop Modifying the Contents of an Array in a Loop Exercise 4.07: Modifying the Contents of an Array in a Loop Activity 4.01: Filling an Array Slice Exercise 4.08: Working with Slices Activity 4.02: Printing a User's Name Based on User Input Appending Multiple Items to a Slice Exercise 4.09: Appending Multiple Items to a Slice Activity 4.03: Creating a Locale Checker Creating Slices from Slices and Arrays Exercise 4.10: Creating Slices from a Slice Understanding Slice Internals Exercise 4.11: Using make to Control the Capacity of a Slice Background Behavior of Slices Exercise 4.12: Controlling Internal Slice Behavior Map Fundamentals Exercise 4.13: Creating, Reading, and Writing a Map Reading from Maps Exercise 4.14: Reading from a Map Activity 4.04: Slicing the Week Deleting Elements from a Map Exercise 4.15: Deleting an Element from a Map Activity 4.05: Removing an Element from a Slice Simple Custom Types Exercise 4.16: Creating a Simple Custom Type Structs Exercise 4.17: Creating Struct Types and Values Comparing Structs to Each Other Exercise 4.18: Comparing Structs to Each Other Struct Composition Using Embedding Exercise 4.19: Struct Embedding and Initialization Type Conversions Exercise 4.20: Numeric Type Conversion Type Assertions and interface{} Exercise 4.21: Type Assertion Type Switch Exercise 4.22: Type Switch Activity 4.06: Type Checker Summary Chapter 5: Functions Introduction Functions Parts of a function fizzBuzz Exercise 5.01: Creating a Function to Print Salesperson Expectation Ratings from the Number of Items Sold Parameters The Difference between an Argument and a Parameter Exercise 5.02: Mapping Index Values to Column Headers Function Variable Scope Return Values Exercise 5.03: Creating a fizzBuzz Function with Return Values Activity 5.01: Calculating the Working Hours of Employees Naked Returns Exercise 5.04: Mapping a CSV Index to a Column Header with Return Values Variadic Function Exercise 5.05: Summing Numbers Anonymous Functions Exercise 5.06: Creating an Anonymous Function to Calculate the Square Root of a Number Closures Exercise 5.07: Creating a Closure Function to Decrement a Counter Function Types Exercise 5.08: Creating Various Functions to Calculate Salary defer Activity 5.02: Calculating Payable Amount for Employees Based on Working Hours Summary Chapter 6: Errors Introduction What Are Errors? Syntax Errors Runtime Errors Exercise 6.01: Runtime Errors While Adding Numbers Semantic Errors Exercise 6.02: Logic Error with Walking Distance Error Handling Using Other Programming Languages Error Interface Type Creating Error Values Exercise 6.03: Creating an Application to Calculate Pay for the Week Panic Exercise 6.04: Crashing the Program on Errors Using panic Recover Exercise 6.05: Recovering from a Panic Guidelines when working with Errors and Panic Activity 6.01: Creating a Custom Error Message for a Banking Application Activity 6.02: Validating a Bank Customer's Direct Deposit Submission Activity 6.03: Panic on Invalid Data Submission Activity 6.04: Preventing a Panic from Crashing the App Summary Chapter 7: Interfaces Introduction Interface Defining an Interface Implementing an Interface Advantages of Implementing Interfaces Implicitly Exercise 7.01: Implementing an Interface Duck Typing Polymorphism Exercise 7.02: Calculating the Area of Different Shapes Using Polymorphism Accepting Interfaces and Returning Structs Empty interface{} Type Assertion and Switches Exercise 7.03: Analyzing Empty interface{} Data Activity 7.01: Calculating Pay and Performance Review Summary Chapter 8: Packages Introduction Maintainable Reusable Modular What Is a Package? Package Structure Package Naming Package Declarations Exported and Unexported Code GOROOT and GOPATH Package Alias Main Package Exercise 8.01: Creating a Package to Calculate Areas of Various Shapes The init() Function Exercise 8.02: Loading Budget Categories Executing Multiple init() Functions Exercise 8.03: Assigning Payees to Budget Categories Activity 8.01: Creating a Function to Calculate Payroll and Performance Review Summary Chapter 9: Basic Debugging Introduction Methods for Bug-Free Code Code Incrementally and Test Often Writing Unit Tests Handling All Errors Performing Logging Formatting Using fmt Exercise 9.01: Working with fmt.Println Formatting Using fmt.Printf() Additional Options for Formatting Exercise 9.02: Printing Decimal, Binary, and Hex Values Basic Debugging Printing Go Variable Types Exercise 9.03 Printing the Go Representation of a Variable Logging Log Fatal Errors Activity 9.01: Building a Program to Validate Social Security Numbers Summary Chapter 10: About Time Introduction Making Time Exercise 10.1: Creating a Function to Return a timestamp Comparing Time Duration Calculation Managing Time Exercise 10.2: Duration of Execution Formatting Time Exercise 10.03: What Is the Time in Your Zone? Activity 10.01: Formatting a Date According to User Requirements Activity 10.02: Enforcing a Specific Format of Date and Time Activity 10.03: Measuring Elapsed Time Activity 10.04: Calculating the Future Date and Time Activity 10.05: Printing the Local Time in Different Time Zones Summary Chapter 11: Encoding and Decoding (JSON) Introduction JSON Decoding JSON Struct Tags Exercise 11.01: Unmarshaling Student Courses Encoding JSON Exercise 11.02: Marshaling Student Courses Unknown JSON Structures Exercise 11.03: Analyzing College Class JSON GOB: Go's Own Encoding Exercise 11.04: Using gob to Encode Data Activity 11.01: Mimicking a Customer Order Using JSON Summary Chapter 12: Files and Systems Introduction Filesystem File Permissions Flags and Arguments Signals Exercise 12.01: Simulating Cleanup Creating and Writing to Files Reading the Whole File at Once Exercise 12.02: Backing Up Files CSV Activity 12.01: Parsing Bank Transaction Files Summary Chapter 13: SQL and Databases Introduction The Database Database API and Drivers Connecting to Databases Creating Tables Inserting Data Exercise 13.01: Creating a Table with Numbers Retrieving Data Updating Existing Data Deleting Data Exercise 13.02: Holding Prime Numbers in a Database Truncating and Deleting Table Activity 13.01: Holding User Data in a Table Activity 13.02: Finding Messages of Specific Users Summary Chapter 14: Using the Go HTTP Client Introduction The Go HTTP Client and Its Uses Sending a Request to a Server Exercise 14.01: Sending a Get Request to a Web Server Using the Go HTTP Client Structured Data Exercise 14.02: Using the HTTP Client with Structured Data Activity 14.01: Requesting Data from a Web Server and Processing the Response Sending Data to a Server Exercise 14.03: Sending a Post Request to a Web Server Using the Go HTTP Client Uploading Files in a Post Request Exercise 14.04: Uploading a File to a Web Server via a Post Request Custom Request Headers Exercise 14.05: Using Custom Headers and Options with the Go HTTP Client Activity 14.02: Sending Data to a Web Server and Checking Whether the Data Was Received Using POST and GET Summary Chapter 15: HTTP Servers Introduction How to Build a Basic Server HTTP Handler Exercise 15.01: Creating a Hello World Server Simple Routing Exercise 15.02: Routing Our Server Handler versus Handler Function Activity 15.01: Adding a Page Counter to an HTML Page Returning Complex Structures Activity 15.02: Serving a Request with a JSON Payload Dynamic Content Exercise 15.03: Personalized Welcome Templating Exercise 15.04: Templating Our Pages Static Resources Exercise 15.05: Creating a Hello World Server Using a Static File Getting Some Style Exercise 15.06: A Stylish Welcome Getting Dynamic Activity 15.03: External Template HTTP Methods Exercise 15.07: Completing a Questionnaire JSON loads Exercise 15.08: Building a Server That Accepts JSON Requests Summary Chapter 16: Concurrent Work Introduction Goroutines Exercise 16.01: Using Concurrent Routines WaitGroup Exercise 16.02: Experimenting with WaitGroup Race Conditions Atomic Operations Exercise 16.03: An Atomic Change Invisible Concurrency Activity 16.01: Listing Numbers Channels Exercise 16.04: Exchange Greeting Messages via Channels Exercise 16.05: Two-Way Message Exchange with Channels Exercise 16.06: Sum Numbers from Everywhere Exercise 16.07: Request to Goroutines The Importance of Concurrency Exercise 16.08: Equally Splitting the Work between Routines Concurrency Patterns Activity 16.02: Source Files Buffers Exercise 16.09: Notifying When Computation Has Finished Some More Common Practices HTTP Servers Methods as Routines Exercise 16.10: A Structured Work Go Context Package Exercise 16.11: Managing Routines with Context Summary Chapter 17: Using Go Tools Introduction The go build Tool Exercise 17.01: Using the go build Tool The go run Tool Exercise 17.02: Using the go run Tool The gofmt Tool Exercise 17.03: Using the gofmt Tool The goimports Tool Exercise 17.04: Using the goimports Tool The go vet Tool Exercise 17.05: Using the go vet Tool The Go Race Detector Exercise 17.06: Using the Go Race Detector The go doc Tool Exercise 17.07: Implementing the go doc Tool The go get Tool Exercise 17.08: Implementing the go get Tool Activity 17.01: Using gofmt, goimport, go vet, and go get to Correct a File Summary Chapter 18: Security Introduction Application Security SQL Injection Command Injection Exercise 18.01: Handling SQL Injection Cross-Site Scripting Exercise 18.02: Handling XSS Attacks Cryptography Hashing Libraries Exercise 18.03: Using Different Hashing Libraries Encryption Symmetric Encryption Exercise 18.04: Symmetric Encryption and Decryption Asymmetric Encryption Exercise 18.05: Asymmetric Encryption and Decryption Random Generators Exercise 18.06: Random Generators HTTPS/TLS Exercise 18.07: Generating a Certificate and Private Key Exercise 18.08: Running an HTTPS Server Password Management Activity 18.01: Authenticating Users on the Application Using Hashed Passwords Activity 18.02: Creating CA Signed Certificates Using Crypto Libraries Summary Chapter 19: Special Features Introduction Build Constraints Build Tags Filenames Reflection TypeOf and ValueOf Exercise 19.01: Using Reflection Activity 19.01: Defining Build Constraints Using Filenames DeepEqual Wildcard Pattern The unsafe Package Exercise 19.02: Using cgo with unsafe Activity 19.02: Using Wildcard with Go Test Summary Appendix Index Get started with Go and learn how to leverage its simplicity and flexibility to solve real-world problems and build practical softwareKey FeaturesBuild a comprehensive foundation in Go and focus on developing real-world applicationsExplore the Go Standard Library and learn how to structure your codeLearn how to efficiently interact with files, databases and REST APIsBook DescriptionThe Go Workshop will take the pain out of learning the Go programming language (also known as Golang). It is designed to teach you to be productive in building real-world software. Presented in an engaging, hands-on way, this book focuses on the features of Go that are used by professionals in their everyday work. Each concept is broken down, clearly explained, and followed up with activities to test your knowledge and build your practical skills. Your first steps will involve mastering Go syntax, working with variables and operators, and using core and complex types to hold data. Moving ahead, you will build your understanding of programming logic and implement Go algorithms to construct useful functions. As you progress, you'll discover how to handle errors, debug code to troubleshoot your applications, and implement polymorphism using interfaces. The later chapters will then teach you how to manage files, connect to a database, work with HTTP servers and REST APIs, and make use of concurrent programming. Throughout this Workshop, you'll work on a series of mini projects, including a shopping cart, a loan calculator, a working hours tracker, a web page counter, a code checker, and a user authentication system. By the end of this book, you'll have the knowledge and confidence to tackle your own ambitious projects with Go.What you will learnUnderstand Go syntax and use it to handle data and write functionsDebug your Go code to troubleshoot development problemsSafely handle errors and recover from panicsImplement polymorphism by using interfacesWork with files and connect to external databasesCreate a HTTP client and server and work with a RESTful web APIUse concurrency to design software that can multitaskUse Go Tools to simplify development and improve your codeWho this book is forThe Go Workshop is designed for anyone who is new to Go. Whether you're beginning your journey as an aspiring developer, or are experienced with another programming language and want to branch out to something new, this book will get you on the right track. No prior programming experience is necessary.