book

Learning Go Programming

Name: Learning Go Programming
Author: Vladimir Vivien
ISBN: 9781784395438

by Vladimir Vivien

October 2016

Beginner

348 pages

6h 31m

English

Packt Publishing

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Learning Go Programming
Learning Go Programming
Credits
About the Author
About the Reviewers
www.PacktPub.com
Why subscribe?
Preface
What this book covers
What you need for this book
Who this book is for
Conventions

Reader feedback
Customer support
Downloading the example codeDownloading the color images of this bookErrataPiracyQuestions
1. A First Step in Go
The Go programming language
Playing with Go
No IDE requiredInstalling GoSource code examples
Your first Go program
Go in a nutshell
FunctionsPackagesThe workspaceStrongly typedComposite typesThe named typeMethods and objectsInterfacesConcurrency and channelsMemory management and safetyFast compilationTesting and code coverageDocumentationAn extensive libraryThe Go Toolchain
Summary
2. Go Language Essentials
The Go source fileOptional semicolonMultiple lines
Go identifiers
The blank identifierMuting package importsMuting unwanted function resultsBuilt-in identifiersTypesValuesFunctions
Go variables
Variable declarationThe zero-valueInitialized declarationOmitting variable typesShort variable declarationRestrictions for short variable declarationVariable scope and visibilityVariable declaration block
Go constants
Constant literalsTyped constantsUntyped constantsAssigning untyped constantsConstant declaration blockConstant enumerationOverriding the default enumeration typeUsing iota in expressionsSkipping enumerated values
Go operators
Arithmetic operatorsThe increment and decrement operatorsGo assignment operatorsBitwise operatorsLogical OperatorsComparison operatorsOperator precedence
Summary
3. Go Control Flow
The if statementThe if statement initialization
Switch statements
Using expression switchesThe fallthrough casesExpressionless switchesSwitch initializerType switches
The for statements
For conditionInfinite loopThe traditional for statementThe for range
The break, continue, and goto statements
The label identifierThe break statementThe continue statementThe goto statement
Summary
4. Data Types
Go types
Numeric types
Unsigned integer typesSigned integer typesFloating point typesComplex number typesNumeric literals
Boolean type
Rune and string types
The runeThe stringInterpreted and raw string literals
Pointers
The pointer typeThe address operatorThe new() functionPointer indirection - accessing referenced values
Type declaration
Type conversion
Summary
5. Functions in Go
Go functionsFunction declarationThe function typeVariadic parametersFunction result parametersNamed result parameters
Passing parameter values
Achieving pass-by-referenceAnonymous Functions and ClosuresInvoking anonymous function literalsClosures
Higher-order functions
Error signaling and handling
Signaling errorsError handlingThe error type
Deferring function calls
Using defer
Function panic and recovery
Function panicFunction panic recovery
Summary
6. Go Packages and Programs
The Go packageUnderstanding the Go packageThe workspaceCreating a workspaceThe import path
Creating packages
Declaring the packageMulti-File packagesNaming packagesUse globally unique namespacesAdd context to pathUse short names
Building packages
Installing a package
Package visibility
Package member visibility
Importing package
Specifying package identifiersThe dot identifierThe blank identifier
Package initialization
Creating programs
Accessing program argumentsBuilding and installing programs
Remote packages
Summary
7. Composite Types
The array typeArray initializationDeclaring named array typesUsing arraysArray length and capacityArray traversalArray as parameters
The slice type
Slice initializationSlice representationSlicingSlicing a sliceSlicing an arraySlice expressions with capacityMaking a sliceUsing slicesSlices as parametersLength and capacityAppending to slicesCopying slicesStrings as slices
The map type
Map initializationMaking MapsUsing mapsMap traversalMap functionsMaps as parameters
The struct type
Accessing struct fieldsStruct initializationDeclaring named struct typesThe anonymous fieldPromoted fieldsStructs as parametersField tags
Summary
8. Methods, Interfaces, and Objects
Go methodsValue and pointer receivers
Objects in Go
The struct as objectObject compositionField and method promotionThe constructor function
The interface type
Implementing an interfaceSubtyping with Go interfacesImplementing multiple interfacesInterface embeddingThe empty interface type
Type assertion
Summary
9. Concurrency
GoroutinesThe go statementGoroutine scheduling
Channels
The Channel typeThe send and receive operationsUnbuffered channelBuffered channelUnidirectional channelsChannel length and capacityClosing a channel
Writing concurrent programs
SynchronizationStreaming dataUsing for…range to receive dataGenerator functionsSelecting from multiple channelsChannel timeout
The sync package
Synchronizing with mutex locksSynchronizing access to composite valuesConcurrency barriers with sync.WaitGroup
Detecting race conditions
Parallelism in Go
Summary
10. Data IO in Go
IO with readers and writers
The io.Reader interface
Chaining readers
The io.Writer interface
Working with the io package
Working with files
Creating and opening filesFunction os.OpenFileFiles writing and readingStandard input, output, and error
Formatted IO with fmt
Printing to io.Writer interfacesPrinting to standard outputReading from io.ReaderReading from standard input
Buffered IO
Buffered writers and readersScanning the buffer
In-memory IO
Encoding and decoding data
Binary encoding with gobEncoding data as JSONControlling JSON mapping with struct tagsCustom encoding and decoding
Summary
11. Writing Networked Services
The net packageAddressingThe net.Conn TypeDialing a connectionListening for incoming connectionsAccepting client connections
A TCP API server
Connecting to the TCP server with telnetConnecting to the TCP server with Go
The HTTP package
The http.Client typeConfiguring the clientHandling client requests and responsesA simple HTTP serverThe default serverRouting requests with http.ServeMuxThe default ServeMux
A JSON API server
Testing the API server with cURLAn API server client in GoA JavaScript API server client
Summary
12. Code Testing
The Go test toolTest file namesTest organization
Writing Go tests
The test functionsRunning the testsFiltering executed testsTest loggingReporting failureSkipping testsTable-driven tests
HTTP testing
Testing HTTP server codeTesting HTTP client code
Test coverage
The cover tool
Code benchmark
Running the benchmarkSkipping test functionsThe benchmark reportAdjusting NComparative benchmarks
Summary

Content preview from Learning Go Programming

Working with files

The os package (https://golang.org/pkg/os/) exposes the os.File type which represents a file handle on the system. The os.File type implements several IO primitives, including the io.Reader and io.Writer interfaces, which allows file content to be processed using the standard streaming IO API.

Creating and opening files

The os.Create function creates a new file with the specified path. If the file already exists, os.Create will overwrite it. The os.Open function, on the other hand, opens an existing file for reading.

The following source snippet opens an existing file and creates a copy of its content using the io.Copy function. One common, and recommended practice to notice is the deferred call to the method Close on the file. ...

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ISBN: 9781784395438

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Learning Go Programming

by Vladimir Vivien

Working with files

Creating and opening files

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