Dynamically add custom ip and domains to host file.

docker_setup_hosts.rb

#!sudo /usr/bin/env ruby

# -----------------------
# HOSTS FILE
#------------------------

# get the ip from a param
container_ip = ARGV[0]

if !container_ip
	exit
end

# domain list seperated by spaces
domains = "example.dev test.example.dev another.example.dev"

# setup the hosts file config
start_tag = "\n#CUSTOM-DOCKER-IP-START\n"
end_tag = "\n#CUSTOM-DOCKER-IP-END\n"
hostConfig = start_tag + container_ip + " " + domains + end_tag

# replace the hosts config
file_name = "/private/etc/hosts"
contents = File.read(file_name)

if contents.match(/#{start_tag}.*#{end_tag}/m)
	new_contents = contents.gsub(/#{start_tag}.*#{end_tag}/m, hostConfig)
else
	new_contents = contents + hostConfig
end

# output the change for temporary
# puts new_contents
File.open(file_name, "w") {|file| file.puts new_contents }