go programming language

Installation in Ubuntu

Important ENV

apt-get install golang

GOPATH

GOROOT

Important commands

go env

go mod init

go version

go list -m all

Example

Example of make chan

package main

import "fmt"

func sum(s []int, c chan int) {

sum := 0

for _, v := range s {

sum += v

}

c <- sum // send sum to c

}

func main() {

//s := []int{7, 2, 8, -9, 4, 0}

s := []int{2,2,4,1,1,1}

c := make(chan int)

c1 := make(chan int)

go sum(s[:len(s)/3], c)

go sum(s[len(s)/3:2*len(s)/3], c1)

go sum(s[2*len(s)/3:], c)

//x, y := <-c, <-c // receive from c

x, y, z := <-c, <-c1, <-c // receive from c

fmt.Println(x, y, z, x+y+z)

}

Output:

2 5 4 11

Useful link: https://tour.golang.org/concurrency/2

Development environment

tags creation

root@minion1:~/personal/foss/dockerhack/cadvisor# apt install ctags

Reading package lists... Done

Building dependency tree

Reading state information... Done

Note, selecting 'exuberant-ctags' instead of 'ctags'

exuberant-ctags is already the newest version (1:5.9~svn20110310-11).

The following packages were automatically installed and are no longer required:

gconf-service gconf-service-backend gconf2 gconf2-common helix-p4d-base-16.1 libavahi-glib1 libbonobo2-0 libbonobo2-common

libbz2-dev libcanberra0 libcurl4-openssl-dev libgconf-2-4 libgnome-2-0 libgnome2-common libgnomevfs2-0 libgnomevfs2-common

libllvm3.8 liborbit-2-0 libruby2.3 libtdb1 libtext-unidecode-perl libvorbisfile3 libxml-libxml-perl

libxml-namespacesupport-perl libxml-parser-perl libxml-sax-base-perl libxml-sax-expat-perl libxml-sax-perl rake ruby

ruby-did-you-mean ruby-minitest ruby-net-telnet ruby-power-assert ruby-test-unit ruby2.3 rubygems-integration

sound-theme-freedesktop tex-common texinfo unzip zip

Use 'apt autoremove' to remove them.

0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.

root@minion1:~/personal/foss/dockerhack/cadvisor# ctags --version

Addresses: <dhiebert@users.sourceforge.net>, http://ctags.sourceforge.net

Optional compiled features: +wildcards, +regex

root@minion1:~/personal/foss/dockerhack/cadvisor# ctags -R ./

ctags: Warning: ignoring null tag in ./pages/assets/js/bootstrap-4.0.0-beta.2.min.js

....

ctags: Warning: ignoring null tag in ./vendor/github.com/influxdb/influxdb/models/points.go

root@minion1:~/personal/foss/dockerhack/cadvisor#

root@minion1:~/personal/foss/dockerhack/cadvisor# ls -l tags

-rw-r--r-- 1 root root 21309119 Jan 27 16:36 tags

root@minion1:~/personal/foss/dockerhack/cadvisor# ls

AUTHORS Makefile cache collector docs info metrics tags vendor

CHANGELOG.md README.md cadvisor.go container events integration pages test.htdigest version

CONTRIBUTING.md accelerators cadvisor.go_1 cscope.out fs logo.png storage test.htpasswd zfs

Godeps api cadvisor_test.go deploy healthz machine storagedriver.go utils

LICENSE build client devicemapper http manager summary validate

root@master1:~/personal/foss/cadvisor# cat tags | grep cadvisor.go | wc -l

25

Tips

- GOPATH is important env variable. it is used by 'go get' which stores the source code in $GOPATH/src

Reference

https://wiki.ubuntu.com/Go

https://tecadmin.net/install-go-on-macos/

https://medium.com/@bnprashanth256/dependency-management-and-vendoring-in-go-golang-5ec6d6b7590e

https://blog.golang.org/migrating-to-go-modules