Go Systems Programming电子书

Title Page

Copyright

Go Systems Programming

Credits

About the Author

About the Reviewer

www.PacktPub.com

Why subscribe?

Customer Feedback

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

Getting Started with Go and Unix Systems Programming

The structure of the book

What is systems programming?

Learning systems programming

About Go

Getting ready for Go

Two useful Go tools

Advantages and disadvantages of Go

The various states of a Unix process

Exercises

Summary

Writing Programs in Go

Compiling Go code

Checking the size of the executable file

Go environment variables

Using command-line arguments

Finding the sum of the command-line arguments

User input and output

Getting user input

Printing output

Go functions

Naming the return values of a Go function

Anonymous functions

Illustrating Go functions

The defer keyword

Using pointer variables in functions

Go data structures

Arrays

Slices

Maps

Converting an array into a map

Structures

Interfaces

Creating random numbers

Exercises

Summary

Advanced Go Features

Error handling in Go

Functions can return error variables

About error logging

The addCLA.go program revisited

Pattern matching and regular expressions

Printing all the values from a given column of a line

Creating summaries

Finding the number of occurrences

Find and replace

Reflection

Calling C code from Go

Unsafe code

Comparing Go to other programming languages

Analysing software

Using the strace(1) command-line utility

The DTrace utility

Disabling System Integrity Protection on macOS

Unreachable code

Avoiding common Go mistakes

Exercises

Summary

Go Packages, Algorithms, and Data Structures

About algorithms

The Big O notation

Sorting algorithms

The sort.Slice() function

Linked lists in Go

Trees in Go

Developing a hash table in Go

About Go packages

Using standard Go packages

Creating your own packages

Private variables and functions

The init() function

Using your own Go packages

Using external Go packages

The go clean command

Garbage collection

Your environment

Go gets updated frequently!

Exercises

Summary

Files and Directories

Useful Go packages

Command-line arguments revisited!

The flag package

Dealing with directories

About symbolic links

Implementing the pwd(1) command

Developing the which(1) utility in Go

Printing the permission bits of a file or directory

Dealing with files in Go

Deleting a file

Renaming and moving files

Developing find(1) in Go

Traversing a directory tree

Visiting directories only!

The first version of find(1)

Adding some command-line options

Excluding filenames from the find output

Excluding a file extension from the find output

Using regular expressions

Creating a copy of a directory structure

Exercises

Summary

File Input and Output

About file input and output

Byte slices

About binary files

Useful I/O packages in Go

The io package

The bufio package

File I/O operations

Writing to files using fmt.Fprintf()

About io.Writer and io.Reader

Finding out the third column of a line

Copying files in Go

There is more than one way to copy a file!

Copying text files

Using io.Copy

Reading a file all at once!

An even better file copy program

Benchmarking file copying operations

Developing wc(1) in Go

Counting words

The wc.go code!

Comparing the performance of wc.go and wc(1)

Reading a text file character by character

Doing some file editing!

Interprocess communication

Sparse files in Go

Reading and writing data records

File locking in Go

A simplified Go version of the dd utility

Exercises

Summary

Working with System Files

Which files are considered system files?

Logging in Go

Putting data at the end of a file

Altering existing data

About log files

About logging

Logging facilities

Logging levels

The syslog Go package

Processing log files

File permissions revisited

Changing file permissions

Finding other kinds of information about files

More pattern matching examples

A simple pattern matching example

An advanced example of pattern matching

Renaming multiple files using regular expressions

Searching files revisited

Finding the user ID of a user

Finding all the groups a user belongs to

Finding files that belong or do not belong to a given user

Finding files based on their permissions

Date and time operations

Playing with dates and times

Reformatting the times in a log file

Rotating log files

Creating good random passwords

Another Go update

Exercises

Summary

Processes and Signals

About Unix processes and signals

Process management

About Unix signals

Unix signals in Go

The kill(1) command

A simple signal handler in Go

Handling three different signals!

Catching every signal that can be handled

Rotating log files revisited!

Improving file copying

Plotting data

Unix pipes in Go

Reading from standard input

Sending data to standard output

Implementing cat(1) in Go

The plotIP.go utility revisited

Unix sockets in Go

RPC in Go

Programming a Unix shell in Go

Yet another minor Go update

Exercises

Summary

Goroutines - Basic Features

About goroutines

Concurrency and parallelism

The sync Go packages

A simple example

Creating multiple goroutines

Waiting for goroutines to finish their jobs

Creating a dynamic number of goroutines

About channels

Writing to a channel

Reading from a channel

Explaining h1s.go

Pipelines

A better version of wc.go

Calculating totals

Doing some benchmarking

Exercises

Summary

Goroutines - Advanced Features

The Go scheduler

The sync Go package

The select keyword

Signal channels

Buffered channels

About timeouts

An alternative way to implement timeouts

Channels of channels

Nil channels

Shared memory

Using sync.Mutex

Using sync.RWMutex

The dWC.go utility revisited

Using a buffered channel

Using shared memory

More benchmarking

Detecting race conditions

About GOMAXPROCS

Exercises

Summary

Writing Web Applications in Go

What is a web application?

About the net/http Go package

Developing web clients

Fetching a single URL

Setting a timeout

Developing better web clients

A small web server

The http.ServeMux type

Using http.ServeMux

The html/template package

About JSON

Saving JSON data

Parsing JSON data

Using Marshal() and Unmarshal()

Using MongoDB

Basic MongoDB administration

Using the MongoDB Go driver

Creating a Go application that displays MongoDB data

Creating an application that displays MySQL data

A handy command-line utility

Exercises

Summary

Network Programming

About network programming

About TCP/IP

About TCP

The TCP handshake!

About UDP and IP

About Wireshark and tshark

About the netcat utility

The net Go standard package

Unix sockets revisited

A Unix socket server

A Unix socket client

Performing DNS lookups

Using an IP address as input

Using a host name as input

Getting NS records for a domain

Developing a simple TCP server

Developing a simple TCP client

Using other functions for the TCP server

Using alternative functions for the TCP client

Developing a simple UDP server

Developing a simple UDP client

A concurrent TCP server

Remote procedure call (RPC)

An RPC server

An RPC client

Exercises

Summary