Development Environment

This is a general guide for setting up development environement using vim on Mac OS X for both Python and Go (golang).

While there are alot of GUI based IDE's available, as a network engineer I spend most of my time in terminals on various operating systems (Windows, Linux and Mac) and find the ubiquity of vim on all platforms (anywhere you can initiate SSH to a remote terminal) to be a valuable tool.

This is my own guide so that I can repeat the setup easily.

Documentation

Most projects come with a README, these are usually written in Markdown or reStructuredText. Here are two Markdown editors for Mac OS X that support a live preview and behave similar to a regular document editor.

• Typora for Mac OS X is here
• MacDown for Mac OS X is here

Currently I am using Typora with great success.

Vim

Install Vim using brew

• brew update
• brew install vim

Had to restart bash after installing new vim

• /usr/local/bin/ should appear before /usr/bin/ in your PATH
• Check vim vesion with vim --version it should be 7.4.

Vim plugins

• mkdir ~/.vim/bundle/

• git clone https://github.com/VundleVim/Vundle.vim.git ~/.vim/bundle/Vundle.vim

Fonts

Having a good font is important and there seems to be some well known font issues with vim Powerline plugin with iTerm on Mac OS X.

• Install fonts (iTerm issues with vim Plugin Powerline)
• git clone https://github.com/powerline/fonts.git
• cd fonts
• ./install.sh
• Make sure you go into iTerm and chage the font to
  • Preferences -> Profiles -> Default -> Text
    • Inconsolata for Powerline

YouCompleteMe

This an autocompletion plugin for vim and supports Python and Go.

• Install through vundle Plugin
  • Edit .vimrc adding Plugin 'Valloric/YouCompleteMe'
  • Save and restart vim or reload .vimrc
  • In vim run :PluginInstall
• cd ~/.vim/bundle/YouCompleteMe/
• ./install.py --gocode-completer --clang-completer

Colours

• git clone https://github.com/fatih/molokai.git
• git clone https://github.com/jnurmine/Zenburn.git
• git clone https://github.com/altercation/vim-colors-solarized.git
• git clone https://github.com/morhetz/gruvbox.git

Each .vim file should be placed in the ~/.vim/colors/ directory.

Some of the colors can be installed as Plugins

Plugin 'morhetz/gruvbox'
Plugin 'haensl/mustang-vim'

The colour scheme can then be set in .vimrc

colorscheme mustang

Python

Python is well known interpreted language used for many tasks, for simple tasks through to full applications. It used by network engineers for orchestration, automation, monitoring and reporting.

Python does have some challenges including (but certainly not limited to):

• it's environment (i.e. virtualenv)
• multiprocessing (it has improved but stil is not part of Python's core)
• memory foot print

Python and Vim

• Create a ~/.vim/ftplugin/ directory
• vim ~/.vim/ftplugin/python.vim

setlocal tabstop=4
setlocal softtabstop=4
setlocal shiftwidth=4
setlocal textwidth=100  " Set the terminal width to 100, a more modern approach
setlocal smarttab
setlocal expandtab

Go

Go is a systems programming language introduced by Google. It has several benefits over other languages and generally sits somewhere between a interpreted and a compiled language.

• Install using brew

  • brew update

  • brew install go

After installing Go you can look at the documentation offline simply by running:

• godoc -http=:6060

Alternatively you can do the tour… it will run a server on the localhost on 127.0.0.1:3999.

• gotour

To ensure Go has the necessary binaries within vim run:

• :GoInstallBinaries

Resources

Concurrency

• http://divan.github.io/posts/go_concurrency_visualize/

Go and Vim

• :GoFmt will correct any format errors (like PEP8 for Go), and should be run automatically when :w (on save) when using vim-go.
• Install tagbar
  • brew install ctags
  • Add the following Plugins to the .vimrc

Plugin 'jstemmer/gotags'
Plugin 'majutsushi/tagbar'

Go Resources

• Concurrency
  • https://talks.golang.org/2013/advconc.slide#1
  • https://talks.golang.org/2012/concurrency.slide#1

Go and Networking

Examples

• Ping pong https://gist.github.com/kenshinx/5796276
• GoDoc ICMP https://godoc.org/golang.org/x/net/icmp
• ​

Multicast

Resources

• http://dave.cheney.net/2011/02/19/using-multicast-udp-in-go
• https://gist.github.com/fiorix/9664255

Basic example of Multicast

package main

import (
	"encoding/hex"
	"log"
	"net"
	"time"
)

const (
	srvAddr         = "224.0.0.1:9999"
	maxDatagramSize = 8192
)

func main() {
	go ping(srvAddr)
	serveMulticastUDP(srvAddr, msgHandler)
}

func ping(a string) {
	addr, err := net.ResolveUDPAddr("udp", a)
	if err != nil {
		log.Fatal(err)
	}
	c, err := net.DialUDP("udp", nil, addr)
	for {
		c.Write([]byte("hello, world\n"))
		time.Sleep(1 * time.Second)
	}
}

func msgHandler(src *net.UDPAddr, n int, b []byte) {
	log.Println(n, "bytes read from", src)
	log.Println(hex.Dump(b[:n]))
}

func serveMulticastUDP(a string, h func(*net.UDPAddr, int, []byte)) {
	addr, err := net.ResolveUDPAddr("udp", a)
	if err != nil {
		log.Fatal(err)
	}
	l, err := net.ListenMulticastUDP("udp", nil, addr)
	l.SetReadBuffer(maxDatagramSize)
	for {
		b := make([]byte, maxDatagramSize)
		n, src, err := l.ReadFromUDP(b)
		if err != nil {
			log.Fatal("ReadFromUDP failed:", err)
		}
		h(src, n, b)
	}
}