onepush

#!/usr/bin/ruby

$LOAD_PATH << '/usr/lib/one/ruby/'
Gem.paths = {
  'GEM_PATH' => '/usr/share/one/gems-dist'
}

require 'base64'
require 'json'
require 'nokogiri'
require 'opennebula'

def get_vm_host(vm_id)
  c = OpenNebula::Client.new

  vm_pool = OpenNebula::VirtualMachinePool.new(c)
  rc = vm_pool.info_all!
  raise rc.message if OpenNebula.is_error?(rc)

  vm_pool.retrieve_xmlelements("VM[ID=#{vm_id}]/HISTORY_RECORDS/HISTORY[last()]/HOSTNAME")[0] \
    || abort("Machine #{vm_id} does not exist or is not running")

  vm_pool.retrieve_xmlelements("VM[ID=#{vm_id}]/HISTORY_RECORDS/HISTORY[last()]/HOSTNAME")[0].text
end

def query_vm_agent(vm_id, query, host = 'localhost')
  cmd = "virsh -c 'qemu+ssh://#{host}/system' qemu-agent-command one-#{vm_id} '#{query.to_json}'"
  out = `#{cmd}`
  JSON.parse(out)
end

def guest_change_permissions(vm_id, remote_path, permissions)
  host = get_vm_host(vm_id)

  exec_chmod = { 'execute' => 'guest-exec',
                 'arguments' => {
                   'path' => '/bin/chmod',
                   'arg' => [permissions, remote_path]
                }
  }

  query_vm_agent(vm_id, exec_chmod, host)
end

def guest_file_write(vm_id, local_path, remote_path)
  host = get_vm_host(vm_id)
  openfile = { 'execute' => 'guest-file-open',
                 'arguments' => {
                   'path' => remote_path,
                   'mode' => 'w'
                 }
  }

  handle = query_vm_agent(vm_id, openfile, host)['return']

  abort("Couldn't open file #{remote_path} in the guest") unless handle >= 0

  writefile = { 'execute' => 'guest-file-write',
                'arguments' => {
                  'handle' => handle,
                  'buf-b64' => Base64.encode64(File.open(local_path, 'rb').read)
                }
  }

  wstatus = query_vm_agent(vm_id, writefile, host)['return']
  puts("#{wstatus['count']} bytes written from #{local_path} to VM #{vm_id} on #{remote_path}")

  closefile = { 'execute' => 'guest-file-close',
          'arguments' => {'handle' => handle }
  }

  status = query_vm_agent(vm_id, closefile, host)
end

ARGV.length != 3 && abort("Usage: #{ARGV[0]} VM_ID SOURCE_FILE DESTINATION_FILE")

VM_ID, SRC_FILE, DST_FILE = ARGV[0], ARGV[1], ARGV[2]

VM_ID =~ %r{[0-9]+} || abort("#{VM_ID} is not a valid ID for a VM")
File.exist?(SRC_FILE) || abort("File #{SRC_FILE} does not exist")
DST_FILE =~ %r{^(\/[A-z0-9_-]+)+} || abort("Destination file #{DST_FILE} does not look like a valid path")

SRC_PERMISSIONS = (format('%04o', File.stat(SRC_FILE).mode))[3..]


guest_file_write(VM_ID, SRC_FILE, DST_FILE)
guest_change_permissions(VM_ID, DST_FILE, SRC_PERMISSIONS)