Go Guardfile: `bundle exec guard`

Gemfile

source "https://rubygems.org"

gem "guard"
gem "guard-shell"
gem "terminal-notifier" # brew upgrade terminal-notifier
gem "terminal-notifier-guard"

Go Guardfile.rb

require "terminal-notifier-guard"

guard :shell do
  watch(/(.*).go/) do |m|
    puts "m: #{m}" # m: ["file-that-was-modified", "folder-file-sits-inside"]
    
    issues = ""

    `golint #{m.first}`.tap { |res| issues = res }

    puts "\nissues:\n#{issues}" unless issues.empty?

    `go run #{m.first}` if issues.empty?
  end
end

Alternative that works with long running go programs (such as a web server)...

require "terminal-notifier-guard"

$thread_finished = false

def notify(t)
  $thread_finished = true
  t.kill
end

def pattern(str)
  "ps aux | grep '#{str}' | awk '{ print $2 }'"
end

def extract(pid)
  pid.split("\n").last.to_i
end

def cleanup(regex)
  pid   = `#{pattern regex}`
  pid   = extract pid
  `kill #{pid}`
end

guard :shell do
  watch(/(.*).go/) do |m|
    issues = ""

    `golint #{m.first}`.tap { |res| issues = res }

    puts "\nissues:\n#{issues}" unless issues.empty?

    Thread.new { `go run #{m.first}`; notify(Thread.current) } if issues.empty?

    seconds = 10 # threshold to wait for program to complete

    while (seconds > 0)
      break if $thread_finished
      puts "sleeping\n"
      sleep 1
      seconds -= 1
    end

    cleanup("[0-9] go run #{m.first}")
    cleanup("go-build")

    puts "Program finished\n"
  end
end