sshfs-instance

#!/usr/bin/env ruby
#
# Copyright 2017 Victor Penso
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

require 'ostruct'
require 'getoptlong' 
require 'logger'

class System 

  def self.exec(command)
    # Remove line-feed and leading white-space
    #
    command = command.gsub(/^  */,'').gsub(/\n/,' ')
    # Redirect error stream
    command + ' 2>&1'
    $logger.debug "Exec [#{command}]"
    return String.new if $options.dry_run
    # Execute command as subprocess and return the exit code
    pipe = IO.popen(command)
    # Get the process ID from the child
    pid = pipe.pid
    # Read the output from the stream
    output = pipe.read
    # Wait for successful return and pass back the code to the caller
    Process.wait(pid)
    state=$?
    $logger.debug "Returned with #{state}"
    if state == 0
      return output
    else
      $logger.warn "Failed to execute [#{command}]"
      return nil
    end
  end

  def self.run(command)
    command = command.gsub(/^  */,'').gsub(/\n/,' ').lstrip
    $logger.debug "Run [#{command}]"
    system(command) unless $options.dry_run
  end

end


exec_name = File.split(__FILE__)[-1]
HELP = <<EOF
#{exec_name} [<options>] <command> [<arguments>]

<command>
      help                   Show this help information
   l, list                   List all mounts of virtual machines
   m, mount [<path>]         Mount <path> within virtual machine 
                             ('/' root directory by default )
   u, umount                 Umount virtual machine

<options>
  -d, --debug                Show stacktraces in case of errors.
  -h, --help                 Show this help information.
  -r, --root                 Mount as user root.
  -v, --version              Print version number.
EOF

begin

  stdin = $stdin.tty? ? String.new : $stdin.read

  $options = OpenStruct.new
  $options.debug = false
  $options.root = false
  $options.mount_point = 'mnt/'

  $logger = Logger.new($stderr)
  # Adjust the time format used for the logger
  $logger.datetime_format = "%Y-%m-%dT%H:%M:%S"
  $logger.formatter = proc do |severity, datetime, progname, message|
    "[#{datetime.strftime($logger.datetime_format)}] #{severity} -- #{message}\n"
  end
  $logger.level = Logger::WARN


  GetoptLong.new(
    ['--debug','-d',GetoptLong::NO_ARGUMENT],
    ['--help','-h',GetoptLong::NO_ARGUMENT],
    ['--log-level','-L',GetoptLong::REQUIRED_ARGUMENT],
    ['--root','-r',GetoptLong::NO_ARGUMENT],
    ['--version','-v',GetoptLong::NO_ARGUMENT]
  ).each do |opt,arg|
    case opt
    when '--debug'
      $options.debug = true
      $logger.level = Logger::DEBUG
    when '--help'
      $stdout.puts HELP
      exit 0
    when '--log-level'
      $logger.level = case arg
      when 'warn'
        Logger::WARN
      when 'debug'
        Logger::DEBUG
      when 'fatal'
        Logger::FATAL
      else
        Logger::INFO
       end
    when '--root'
    when '--version'
      $stdout.puts 0.1
      exit 0
    end
  end

  command = ARGV.shift || raise('No command given!')
  case command

  when 'help'

    $stdout.puts HELP
     exit 0

  when 'list','l'

    System::run(%Q<mount | grep fuse.sshfs | grep #{ENV['VM_DOMAIN']} | cut -d' ' -f-3>)

  when 'mount','m'

    remote_path = ARGV.shift || '/'

    args = ['-o idmap=user','-o allow_root']
    if  File.exist?("#{ENV['PWD']}/ssh_config")
      args << '-F $PWD/ssh_config'
    else
      raise('Missing SSH configuration for virtual machine in $PWD/ssh_config!')
    end

    if not File.directory? $options.mount_point
      System::run("mkdir #{$options.mount_point}")
    end

    instance = $options.root ? 'instance:' : 'root@instance:'

    cmd = %Q<sshfs #{args.join(' ')} #{instance}#{remote_path} #{$options.mount_point}>
    state = System::exec(cmd)
    if state.nil?
      $stdout.puts "Could not mount :#{remote_path} to #{$options.mount_point}"
    else
      $stdout.puts ":#{remote_path} mounted to #{$options.mount_point}"
    end

  when 'umount','u'

    cmd = %Q[( mount | grep #{$options.mount_point} &>/dev/null ) && fusermount -u #{$options.mount_point}]
    System::exec(cmd)

  else
    raise("Command #{command} not supported!")
  end

rescue => exc
  $stderr.puts "ERROR: #{exc.message}"
  $stderr.puts " use -h for detailed instructions"
  if $options.debug
    $stderr.puts '-- Stack Trace --'
    $stderr.puts exc.backtrace
  else
    $stderr.puts 'You may want run this in debug mode with \'-d\''
  end
  exit 1
end

exit 0