[pve-devel] [RFC container v2 23/25] backup: implement restore for external providers

[Fabian Grünbichler]

On August 13, 2024 3:28 pm, Fiona Ebner wrote:
> First, the provider is asked about what restore mechanism to use.
> Currently, 'directory' and 'tar' are possible, for restoring either
> from a directory containing the full filesystem structure (for which
> rsync is used) or a potentially compressed tar file containing the
> same.
> 
> The new functions are copied and adapted from the existing ones for
> PBS or tar and it might be worth to factor out the common parts.
> 
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
> 
> Changes in v2:
> * Adapt to API changes.
> 
>  src/PVE/LXC/Create.pm | 141 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 141 insertions(+)
> 
> diff --git a/src/PVE/LXC/Create.pm b/src/PVE/LXC/Create.pm
> index 117103c..9d1c337 100644
> --- a/src/PVE/LXC/Create.pm
> +++ b/src/PVE/LXC/Create.pm
> @@ -25,6 +25,24 @@ sub restore_archive {
>  	if ($scfg->{type} eq 'pbs') {
>  	    return restore_proxmox_backup_archive($storage_cfg, $archive, $rootdir, $conf, $no_unpack_error, $bwlimit);
>  	}
> +	my $log_function = sub {
> +	    my ($log_level, $message) = @_;
> +	    my $prefix = $log_level eq 'err' ? 'ERROR' : uc($log_level);
> +	    print "$prefix: $message\n";
> +	};
> +	my $backup_provider =
> +	    PVE::Storage::new_backup_provider($storage_cfg, $storeid, $log_function);
> +	if ($backup_provider) {
> +	    return restore_external_archive(
> +		$backup_provider,
> +		$storeid,
> +		$volname,
> +		$rootdir,
> +		$conf,
> +		$no_unpack_error,
> +		$bwlimit,
> +	    );
> +	}
>      }
>  
>      $archive = PVE::Storage::abs_filesystem_path($storage_cfg, $archive) if $archive ne '-';
> @@ -118,6 +136,55 @@ sub restore_tar_archive {
>      die $err if $err && !$no_unpack_error;
>  }
>  
> +sub restore_external_archive {
> +    my ($backup_provider, $storeid, $volname, $rootdir, $conf, $no_unpack_error, $bwlimit) = @_;
> +
> +    my ($mechanism, $vmtype) = $backup_provider->restore_get_mechanism($volname, $storeid);
> +    die "cannot restore non-LXC guest of type '$vmtype'\n" if $vmtype ne 'lxc';
> +
> +    my $info = $backup_provider->restore_container_init($volname, $storeid, {});
> +    eval {
> +	if ($mechanism eq 'tar') {
> +	    my $tar_path = $info->{'tar-path'}
> +		or die "did not get path to tar file from backup provider\n";
> +	    die "not a regular file '$tar_path'" if !-f $tar_path;
> +	    restore_tar_archive($tar_path, $rootdir, $conf, $no_unpack_error, $bwlimit);

shouldn't this be `lxc-userns-exec`-ed?

> +	} elsif ($mechanism eq 'directory') {
> +	    my $directory = $info->{'archive-directory'}
> +		or die "did not get path to archive directory from backup provider\n";
> +	    die "not a directory '$directory'" if !-d $directory;
> +
> +	    my $rsync = ['rsync', '--stats', '-h', '-X', '-A', '--numeric-ids', '-aH', '--delete',
> +		'--no-whole-file', '--sparse', '--one-file-system', '--relative'];
> +	    push $rsync->@*, '--bwlimit', $bwlimit if $bwlimit;
> +	    push $rsync->@*, "${directory}/./", $rootdir;

and this as well?

also, for both tar and rsync we probably need to think about how to
prevent bogus input here (which might be user-creatable if they have
write access to the backup storage) from violating our assumptions..

> +
> +	    my $transferred = '';
> +	    my $outfunc = sub {
> +		return if $_[0] !~ /^Total transferred file size: (.+)$/;
> +		$transferred = $1;
> +	    };
> +	    my $errfunc = sub { log_warn($_[0]); };
> +
> +	    my $starttime = time();
> +	    PVE::Tools::run_command($rsync, outfunc => $outfunc, errfunc => $errfunc);
> +	    my $delay = time () - $starttime;
> +
> +	    print "sync finished - transferred ${transferred} in ${delay}s\n";