视频版 |《老运维带你用 Golang 飞》

Posted 2020-10-08

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Outline

What is Golang
Syntax
Concurrent
Example
Docker
Useful tools

History

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Design began in late 2007 by Google.
Authors:
Rob Pike (Bell Lab & UTF-8)
Ken Thompson (UNIX & C & Turning Award)
Robert Griesemer (Chrome javascript V8)

Go Users

Google, Facebook, Github, Dropbox, Docker, CloudFlare, DigitalOcean, Baidu BFE, 许式伟…

https://github.com/golang/go/wiki/GoUsers

What is go?

open source
concurrent
garbage-collected
efficient
scalable
simple
http://golang.org
benchmark

Declarations

C syntax

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Go syntax

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For more information:

golang.org/s/decl-syntax

Function syntax

Function on type T:

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Method of type T (Class Method?):

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Variable (closure) of type T:

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Multi return

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Naming

Simple rule:
upper case initial letter: Name is visible to clients of package
otherwise: name (or _Name) is not visible to clients of package
Applies to variables, types, functions, methods, constants, fields....
That Is It.

Pointers and Structs

Go has pointers. A pointer holds the memory address of a variable.

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Reflection

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Garbage collection

In C:

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Auto GC (Mark and Sweep), stop-the-world(-_-)

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see more: http://adamansky.bitbucket.org/slides/gc/index.html?full#1

Problems:

Memory leak or Wild pointer ?

Defer

A defer statement defers the execution of a function until the surrounding function returns.

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Defer StacK

Concurrent

In C:

process, thread, libevent

In Go:

goroutine

channel

select

waitGroup

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Goroutine

A goroutine is a lightweight thread managed by the Go runtime.
Goroutines run in the same address space, so access to shared memory must be synchronized. The sync package provides useful primitives, although you won‘t need them much in Go as there are other primitives. (channel & select)
See more: https://tour.golang.org/concurrency/1
go func() {}
coroutine Python?

Channel

Channels are a typed conduit through which you can send and receive values with the channel operator, <-.

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Don‘t communicate by sharing memory, Share memory by communicating（No Lock !）
http://my.oschina.net/clopopo/blog/141873

Dead lock

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Buffered channel

Buffered channel (like Queue in Python, thread safe FIFO)
Sends to a buffered channel block only when the buffer is full.
Receives to block when the buffer is empty.

Select

The select statement lets a goroutine wait on multiple communication operations.
A select blocks until one of its cases can run, then it executes that case. It chooses one at random if multiple are ready.
The default case in a select is run if no other case is ready.

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WaitGroup

A WaitGroup waits for a collection of goroutines to finish.
Add()
Wait()
Done()
https://github.com/wusuopubupt/go_spider/blob/master/src/spider/spider.go

Example

http://eleme.io/blog/2014/goroutine-1/
https://github.com/wusuopubupt/go_spider
Docker

Docker -- A Go Project

Docker enables developers and IT admins to build, ship and run any application, anywhere.
written in the Golang, released as open source in 2013
Resource isolation(Namespaces, Cgroups, Libcontainer)
https://en.wikipedia.org/wiki/Docker_(software)
https://www.docker.com/
http://www.infoq.com/cn/articles/docker-kernel-knowledge-cgroups-resource-isolation

Docker basic concept

Image (https://hub.docker.com)
container
repository

Dockerfile

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docker build -t 4paradigm/dango-base-lastest . (-t == --tag)
docker run -t -i 4paradigm/dango-base-lastest /bin/bash (-t == --tyy), ip conflict?
See more: https://docs.docker.com/engine/reference/builder/

Dokcer Commands