Re: [pve-devel] [pmg-devel] [PATCH pmg-api v2 5/7] revised task log download function in the PMG backend

[Stefan Sterz <s.sterz@proxmox.com>]

On 9/7/22 10:56, Daniel Tschlatscher wrote:
> With the newly added button in the tasklog the implementation for the
> PMG server needs to be adapted. I saw an opportunity here to clear
> some redundant code for displaying the tasklog and replace it with a
> call to dump_logfile(), akin to how this is handled in pve-manager.
> 
> The tasklog download functionality now streams the file by invoking
> the newly created function in pve-common.
> 
> Signed-off-by: Daniel Tschlatscher <d.tschlatscher@proxmox.com>
> ---
>  src/PMG/API2/Tasks.pm | 34 +++++++++++-----------------------
>  1 file changed, 11 insertions(+), 23 deletions(-)
> 
> diff --git a/src/PMG/API2/Tasks.pm b/src/PMG/API2/Tasks.pm
> index 598fb4d..0fd3780 100644
> --- a/src/PMG/API2/Tasks.pm
> +++ b/src/PMG/API2/Tasks.pm
> @@ -5,6 +5,7 @@ use warnings;
>  use POSIX;
>  use IO::File;
>  use File::ReadBackwards;
> +use File::stat;
>  use PVE::Tools;
>  use PVE::SafeSyslog;
>  use PVE::RESTHandler;
> @@ -272,33 +273,20 @@ __PACKAGE__->register_method({
>  
>  	my $restenv = PMG::RESTEnvironment->get();
>  
> -	my $fh = IO::File->new($filename, "r");
> -	raise_param_exc({ upid => "no such task - unable to open file - $!" }) if !$fh;
> +	my $start = $param->{start} // 0;
> +	my $limit = $param->{limit} // 50;
>  
> -	my $start = $param->{start} || 0;
> -	my $limit = $param->{limit} || 50;
> -	my $count = 0;
> -	my $line;
> -	while (defined ($line = <$fh>)) {
> -	    next if $count++ < $start;
> -	    next if $limit <= 0;
> -	    chomp $line;
> -	    push @$lines, { n => $count, t => $line};
> -	    $limit--;
> -	}
> +	if ($limit == 0) {
> +	    # TCP Max Transfer Unit size is 1500, compression for lower numbers has no effect
> +	    my $use_compression = stat($filename)->size > 1500;
> +	    return PVE::Tools::stream_logfile($filename, $param->{upid}, $use_compression);

I am pretty sure that should be `stream_file` and not `stream_logfile`.
We've already discussed this off list, but I wanted to document it here too.

> +	} else {
> +	    my ($count, $lines) = PVE::Tools::dump_logfile($filename, $start, $limit);
>  
> -	close($fh);
> +	    $restenv->set_result_attrib('total', $count);
>  
> -	# HACK: ExtJS store.guaranteeRange() does not like empty array
> -	# so we add a line
> -	if (!$count) {
> -	    $count++;
> -	    push @$lines, { n => $count, t => "no content"};
> +	    return $lines;
>  	}
> -
> -	$restenv->set_result_attrib('total', $count);
> -
> -	return $lines;
>      }});
>  
>