Introduction 1
About This Book 1
Foolish Assumptions 2
Icons Used in This Book 2
Beyond the Book 3
Where to Go from Here 3
Part 1: Getting Started with Go 5
Chapter 1: Hello, Go! 7
Seeing What Learning Go Can Do for You 8
Installing Go on Your Machine 9
macOS 10
Windows 11
Using an Integrated Development Environment with Go 12
Writing Your First Go Program 14
Compiling and running the program 15
Understanding how a Go program works 17
Making sense of the Go file structure 18
Compiling for multiple operating systems 19
Comparing Go with Other Languages 21
Syntax 21
Compilation 22
Concurrency 22
Library support 22
Chapter 2: Working with Different Data Types 23
Declaring Always-Changing Variables 24
Using the var keyword: Type-inferred variables 24
Specifying the data type: Explicitly typed variables 25
Using the short variable declaration operator 26
Declaring Never-Changing Constants 27
Removing Unused Variables 27
Dealing with Strings 29
Performing Type Conversions 30
Discovering the type of a variable 31
Converting a variable’s type 32
Interpolating strings 34
Chapter 3: Making Decisions 37
Using If/Else Statements to Make Decisions 37
Laying the foundation for the if/else statement: Logical and comparison operators 38
Using the if/else statement 40
Short-circuiting: Evaluating conditions in Go 42
When You Have Too Many Conditions: Using the Switch Statement 46
Switching with fall-throughs 47
Matching multiple cases 48
Switching without condition 48
Chapter 4: Over and Over and Over: Using Loops 51
Performing Loops Using the for Statement 51
Iterating over a Range of Values 56
Iterating through arrays/slices 56
Iterating through a string 58
Using Labels with the for Loop 59
Chapter 5: Grouping Code into Functions 65
Defining a Function 65
Defining functions with parameters 66
Defining functions with multiple parameters 68
Passing arguments by value and by pointer 68
Returning values from functions 71
Naming return values 72
Working with variadic functions 72
Using Anonymous Functions 73
Declaring an anonymous function 73
Implementing closure using anonymous functions 74
Implementing the filter() function using closure 76
Part 2: Working with Data Structures 79
Chapter 6: Slicing and Dicing Using Arrays and Slices 81
Arming Yourself to Use Arrays 81
Declaring an array 82
Initializing an array 83
Working with multidimensional arrays 83
Sleuthing Out the Secrets of Slices 86
Creating an empty slice 86
Creating and initializing a slice 88
Appending to a slice 88
Slicing and Ranging 92
Extracting part of an array or slice 92
Iterating through a slice 95
Making copies of an array or slice 95
Inserting an item into a slice 97
Removing an item from a slice 99
Chapter 7: Defining the Blueprints of Your Data Using Structs 101
Defining Structs for a Collection of Items 101
Creating a Go Struct 104
Making a Copy of a Struct 105
Defining Methods in Structs 107
Comparing Structs 110
Chapter 8: Establishing Relationships Using Maps 113
Creating Maps in Go 113
Initializing a map with a map literal 115
Checking the existence of a key 115
Deleting a key 116
Getting the number of items in a map 116
Iterating over a map 117
Getting all the keys in a map 117
Setting the iteration order in a map 118
Sorting the items in a map by values 118
Using Structs and Maps in Go 121
Creating a map of structs 121
Sorting a map of structs 124
Chapter 9: Encoding and Decoding Data Using JSON 129
Getting Acquainted with JSON 129
Object 130
String 130
Boolean 131
Number 131
Object 132
Array 132
null 133
Decoding JSON 134
Decoding JSON to a struct 135
Decoding JSON to arrays 136
Decoding embedded objects 137
Mapping custom attribute names 140
Mapping unstructured data 141
Encoding JSON 144
Encoding structs to JSON 144
Encoding interfaces to JSON 148
Chapter 10: Defining Method Signatures Using Interfaces 151
Working with Interfaces in Go 152
Defining an interface 152
Implementing an interface 153
Looking at How You May Use Interfaces 154
Adding methods to a type that doesn’t satisfy an interface 158
Using the Stringer interface 159
Implementing multiple interfaces 160
Using an empty interface 161
Determining whether a value implements a specific interface 162
Part 3: Multitasking in Go 163
Chapter 11: Threading Using Goroutines 165
Understanding Goroutines 166
Using Goroutines with Shared Resources 168
Seeing how shared resources impact goroutines 168
Accessing shared resources using mutual exclusion 171
Using atomic counters for modifying shared resources 172
Synchronizing Goroutines 174
Chapter 12: Communicating between Goroutines Using Channels 179
Understanding Channels 179
How channels work 180
How channels are used 183
Iterating through Channels 186
Asynchronously Waiting on Channels 187
Using Buffered Channels 192
Part 4: Organizing Your Code 195
Chapter 13: Using and Creating Packages in Go 197
Working with Packages 197
Creating shareable packages 200
Organizing packages using directories 202
Using Third-Party Packages 204
Emojis for Go 204
Go Documentation 205
Chapter 14: Grouping Packages into Modules 211
Creating a Module 211
Testing and Building a Module 214
Publishing a Module on GitHub 216
Part 5: Seeing Go in Action 223
Chapter 15: Consuming Web APIs Using Go 225
Understanding Web APIs 225
Fetching Data from Web Services in Go 226
Writing a Go program to connect to a web API 227
Decoding JSON data 229
Refactoring the code for decoding JSON data 233
Fetching from multiple web services at the same time 238
Returning Goroutine’s results to the main() function 239
Chapter 16: Getting Ready to Serve Using REST APIs 243
Building Web Services Using REST APIs 243
HTTP messages 244
REST URLs 244
REST methods 246
REST response 248
Creating a REST API in Go 249
Getting your REST API up and running 249
Testing the REST API 251
Registering additional paths 251
Passing in query string 254
Specifying request methods 255
Storing the course information on the REST API 257
Testing the REST API again 267
Chapter 17: Working with Databases 271
Setting Up a MySQL Database Server 272
Interfacing with the MySQL server 272
Creating a database and table 274
Creating a new account and granting permission 275
Connecting to the MySQL Database in Go 276
Retrieving a record 278
Adding a record 280
Modifying a record 281
Deleting a record 283
Part 6: The Part of Tens 285
Chapter 18: Ten Useful Go Packages to Create Applications 287
color 287
Installation 288
Code sample 288
now 288
Installation 288
Code sample 288
go-pushbullet 289
Installation 289
Code sample 289
goid 290
Installation 290
Code sample 290
json2go 291
Installation 291
Code sample 291
gojq 292
Installation 293
Code sample 293
turtle 294
Installation 294
Code sample 294
go-http-client 295
Installation 295
Code sample 295
notify 296
Installation 296
Code sample 296
gosx-notifier 297
Installation 297
Code sample 297
Chapter 19: Ten Great Go Resources 299
The Official Go Website 299
Go by Example 300
A Tour of Go 300
The Go Frequently Asked Questions 300
The Go Playground 300
Go Bootcamp 301
Effective Go 301
Gophercises 301
Tutorialspoint 301
Stack Overflow 302
Index 303
