File hugo-deployer of Package hugo-compress-site

#!/usr/bin/ruby
#
# License: GNU Affero General Public License v3.0 only
#

require 'fileutils'
require 'logger'

class DeployHugo
  def initialize
    @loglog = Logger.new(STDERR)
    @loglog.level = Logger::INFO
    # @loglog.datetime_format = ''
    ssh_dir_path      = File.expand_path("~/.ssh")
    @known_hosts_path  = "#{ssh_dir_path}/deployer_known_hosts"
    @key_file_path     = "#{ssh_dir_path}/deployer_id_ed25519"

    old_umask = File.umask(0077)
    if FileUtils.mkdir_p(ssh_dir_path)
      @known_hosts_path = write_env_var_to_file('DEPLOY_KNOWN_HOSTS', @known_hosts_path, 1)
      @key_file_path    = write_env_var_to_file('DEPLOY_KEY',         @key_file_path,    2)

      deploy_target     = envvar_or_error_out('DEPLOY_TARGET', 3)

      unless(system("hugo-compress-site public"))
        fail_with_message("Compressing the site failed", 4)
      end

      permissions='u=rwX,go=rX'
      @loglog.info("Fixing permissions do #{permissions} ...")
      FileUtils.chmod_R(permissions, "public", verbose: true)

      @loglog.info("Running rsync ...")
      exit(system("rsync --archive --update --human-readable --delete-after -e 'ssh -o UserKnownHostsFile=#{@known_hosts_path} -i #{@key_file_path} -o LogLevel=error' public/ #{deploy_target}/"))
    end
  end

  def write_env_var_to_file(envvar, path, code)
    @loglog.info("Writing #{path} ...")
    value=envvar_or_error_out(envvar, code)
    if File.exist?(value)
      @loglog.info("The path #{path} is already a file switching from #{path} to #{value}")
      return value
    end

    value_length = value.length
    written_bytes_count = File.write(path, value)

    if value_length != written_bytes_count
      fail_with_message("Only wrote #{written_bytes_count} instead of expected #{value_length} to #{path}. Exiting ...")
    end

    path
  end

  def envvar_or_error_out(envvar, code=1)
    return ENV[envvar] if ENV.include?(envvar)
    fail_with_message("env var #{envvar} missing. Exiting ...")
  end

  def fail_with_message(message, code)
    @loglog.error(message)
    exit(code)
  end
end

DeployHugo.new