[pve-devel] applied: [PATCH common v3] run_fork_with_timeout: allow returning complex structures

[Wolfgang Bumiller]

applied

On Tue, Sep 12, 2017 at 01:25:30PM +0200, Thomas Lamprecht wrote:
> Encode the result or the error in JSON. This way complex objects or
> exceptions may be passed to the parent in a generic way.
> 
> This allows to remove the second pipe 'pipe_err'.
> 
> Allow also to return undef without any warnings to our caller.
> This avoids a "use of uninitialized variable ..." warning
> 
> Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
> ---
> 
> changes v2 -> v3:
>  * adapt Dietmars idea and use JSON for serialization, which then
>    allows to omit the second pipe
> 
>  src/PVE/Tools.pm | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
> index 81662b1..3080b3e 100644
> --- a/src/PVE/Tools.pm
> +++ b/src/PVE/Tools.pm
> @@ -20,6 +20,7 @@ use base 'Exporter';
>  use URI::Escape;
>  use Encode;
>  use Digest::SHA;
> +use JSON;
>  use Text::ParseWords;
>  use String::ShellQuote;
>  use Time::HiRes qw(usleep gettimeofday tv_interval alarm);
> @@ -905,7 +906,6 @@ sub run_fork_with_timeout {
>      my $res;
>      my $error;
>      my $pipe_out = IO::Pipe->new();
> -    my $pipe_err = IO::Pipe->new();
>  
>      # disable pending alarms, save their remaining time
>      my $prev_alarm = alarm 0;
> @@ -922,35 +922,33 @@ sub run_fork_with_timeout {
>  
>      if (!$child) {
>  	$pipe_out->writer();
> -	$pipe_err->writer();
>  
>  	eval {
>  	    $res = $sub->();
> -	    print {$pipe_out} "$res";
> +	    print {$pipe_out} encode_json({ result => $res });
>  	    $pipe_out->flush();
>  	};
>  	if (my $err = $@) {
> -	    print {$pipe_err} "$err";
> -	    $pipe_err->flush();
> +	    print {$pipe_out} encode_json({ error => $err });
> +	    $pipe_out->flush();
>  	    POSIX::_exit(1);
>  	}
>  	POSIX::_exit(0);
>      }
>  
>      $pipe_out->reader();
> -    $pipe_err->reader();
>  
>      my $readvalues = sub {
>  	local $/ = undef;
> -	$res = <$pipe_out>;
> -	$error = <$pipe_err>;
> +	my $child_res = decode_json(scalar<$pipe_out>);
> +	$res = $child_res->{result};
> +	$error = $child_res->{error};
>      };
>      eval {
>  	run_with_timeout($timeout, $readvalues);
>      };
>      warn $@ if $@;
>      $pipe_out->close();
> -    $pipe_err->close();
>      kill('KILL', $child);
>      waitpid($child, 0);
>  
> -- 
> 2.11.0