
=head1 名前

guestfs-lua - How to use libguestfs from Lua

=head1 書式

 local G = require "guestfs"
 g = G.create ()
 g:add_drive ("test.img", { format = "raw", readonly = true })
 g:launch ()
 devices = g:list_devices ()
 g:close ()

=head1 説明

This manual page documents how to call libguestfs from the Lua programming language.  This page just documents the differences from the C API and gives some examples.  If you are not familiar with using libguestfs, you also need to read L<guestfs(3)>.

=head2 REQUIRING THE MODULE

C<require "guestfs"> returns the module, so you have to assign it to a local variable.  Typical usage is:

 local G = require "guestfs"

(you can use any name you want instead of C<G>, but in the examples in this man page we always use C<G>).

=head2 ハンドルのオープン方法およびクローズ方法

To create a new handle, call:

 g = G.create ()

You can also use the optional arguments:

 g = G.create { environment = 0, close_on_exit = 0 }

to set the flags C<GUESTFS_CREATE_NO_ENVIRONMENT> and/or C<GUESTFS_CREATE_NO_CLOSE_ON_EXIT>.

The handle will be closed by the garbage collector, but you can also close it explicitly by doing:

 g:close ()

=head2 CALLING METHODS

Use the ordinary Lua convention for calling methods on the handle.  For example:

 g:set_verbose (true)

=head2 オプション引数を用いた機能

For functions that take optional arguments, the first arguments are the non-optional ones.  The optional final argument is a table supplying the optional arguments.

 g:add_drive ("test.img")

または:

 g:add_drive ("test.img", { format = "raw", readonly = true })

=head2 64 BIT VALUES

Currently 64 bit values must be passed as strings, and are returned as strings.  This is because 32 bit Lua cannot handle 64 bit integers properly.  We hope to come up with a better solution later.

=head2 エラー

Most (but not all) errors are converted into objects (ie. tables) containing the following fields:

=over 4

=item msg

The error message (corresponding to L<guestfs(3)/guestfs_last_error>).

=item code

The C<errno> (corresponding to L<guestfs(3)/guestfs_last_errno>).

=back

These objects also have C<__tostring> functions attached to them so you can use C<tostring> (or implicit conversion) to convert them into printable strings.

Note that the library also throws some errors as plain strings.  You may need to check the type.

=head2 イベント

Events can be registered by calling C<set_event_callback>:

 eh = g:set_event_callback (cb, "close")

or to register a single callback for multiple events make the second argument a list:

 eh = g:set_event_callback (cb, { "appliance", "library", "trace" })

A list of all valid event types (strings) is in the global variable C<G.event_all>.

The callback (C<cb>) is called with the following parameters:

 function cb (g, event, eh, flags, buf, array)
   -- g is the guestfs handle
   -- event is a string which is the name of the event that fired
   -- flags is always zero
   -- buf is the data buffer (eg. log message etc)
   -- array is the array of 64 bit ints (eg. progress bar status etc)
   ...
 end

You can also remove a callback using the event handle (C<eh>) that was returned when you registered the callback:

 g:delete_event_callback (eh)

=head1 例 1: ディスクイメージの作成

@EXAMPLE1@

=head1 例 2: 仮想マシンのディスクイメージの検査

@EXAMPLE2@

=head1 関連項目

L<guestfs(3)>, L<guestfs-examples(3)>, L<guestfs-erlang(3)>, L<guestfs-gobject(3)>, L<guestfs-golang(3)>, L<guestfs-java(3)>, L<guestfs-ocaml(3)>, L<guestfs-perl(3)>, L<guestfs-python(3)>, L<guestfs-recipes(1)>, L<guestfs-ruby(3)>, L<http://www.lua.org/>, L<http://libguestfs.org/>.

=head1 著者

Richard W.M. Jones (C<rjones at redhat dot com>)

=head1 COPYRIGHT

Copyright (C) 2012 Red Hat Inc.

