Elixir Deploy Script with Versioning Niceties

deploy.rb

#!/usr/bin/ruby

require 'optparse'

FILE_NAME = 'VERSION.txt'
options = {}

def red(str);   "\e[31m#{str}\e[0m"; end
def green(str); "\e[32m#{str}\e[0m"; end

def parse_version(version)
  version.split(".").map(&:to_i)
end

def combine_version(major, minor, patch)
  [major, minor, patch].map(&:to_s).join(".")
end

def increment_major(version)
  major, minor, patch = parse_version(version)
  combine_version(major + 1, 0, 0)
end

def increment_minor(version)
  major, minor, patch = parse_version(version)
  combine_version(major, minor + 1, 0)
end

def increment_patch(version)
  major, minor, patch = parse_version(version)
  combine_version(major, minor, patch + 1)
end

OptionParser.new do |opts|
  opts.banner = "Usage: deploy.rb [options]"

  opts.on("-s", "--set [VERSION]", "Manually set version") do |v|
    options[:version] = v
  end

  opts.on("-M", "--major", "Increment major version") do |o|
    options[:major] = o
  end

  opts.on("-m", "--minor", "Increment minor version") do |o|
    options[:minor] = o
  end

  opts.on("-p", "--patch", "Increment patch version (default)") do |o|
    options[:patch] = o
  end

  opts.on("-d", "--dry-run", "Dry run (do not bump version, commit changes, or build release") do |o|
    options[:dry_run] = o
  end
end.parse!

# read version
old_version = File.read(FILE_NAME).strip

new_version =
  if options[:version]
    puts "#{red("manually")} setting version"
    options[:version]
  elsif options[:major]
    puts "incrementing #{red("MAJOR")} version"
    increment_major(old_version)
  elsif options[:minor]
    puts "incrementing #{red("MINOR")} version"
    increment_minor(old_version)
  else
    puts "incrementing #{red("PATCH")} version"
    increment_patch(old_version)
  end

puts "#{green("#{old_version} -> #{new_version}")}\n\n"

exit if options[:dry_run]

# write new version
open(FILE_NAME, 'w') { |f| f.puts new_version }

# commit, add tag
system %(git add #{FILE_NAME})
system %(git commit -m "bump version")
system %(git tag -a v#{new_version} -m "release version #{new_version}")
system %(git push --tags)

# build release
exec "mix edeliver build release && mix edeliver deploy release to production --start-deploy --version=#{new_version}"