[pmg-devel] [PATCH pmg-api] backup: restore: keep relevant subdirs in /etc/pmg for inotify

[Stoiko Ivanov]

On Wed, Nov 30, 2022 at 02:46:16PM +0100, Fiona Ebner wrote:
> Am 30.11.22 um 09:27 schrieb Stoiko Ivanov:
> > By wiping the subdirectories in /etc/pmg/, we lose the inotify
> > watchers upon restore (/etc/pmg itself and thus most configs are
> > currently handled by the keep_root flag to rmtree)
> > This can lead to inconsistencies after restoring for parts relying on
> > config in a subdirectory (e.g. /etc/pmg/pbs/pbs.conf).
> > 
> > This patch keeps a list of relevant config directories in place by
> > iterating over all entries and checking if they should be kept.
> > 
> > an alternative approach would be to simply reload pmgdaemon/pmgproxy
> > upon config-restore, but that feels more likely to miss some
> > (potentially future) service, expecting inotify to work.
> > 
> > Reported-by: Fiona Ebner <f.ebner at proxmox.com>
> 
> Tested-by: Fiona Ebner <f.ebner at proxmox.com>
Thanks for testing!

> 
> > Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
> > ---
> > Huge Thanks to Fiona for not only reporting, but also analyzing the issue!
> > 
> >  src/PMG/Backup.pm | 31 ++++++++++++++++++++++++++++---
> >  1 file changed, 28 insertions(+), 3 deletions(-)
> > 
> > diff --git a/src/PMG/Backup.pm b/src/PMG/Backup.pm
> > index a46167c..71193e9 100644
> > --- a/src/PMG/Backup.pm
> > +++ b/src/PMG/Backup.pm
> > @@ -8,7 +8,7 @@ use File::Path;
> >  use POSIX qw(strftime);
> >  
> >  use PVE::JSONSchema qw(get_standard_option);
> > -use PVE::Tools;
> > +use PVE::Tools qw(dir_glob_foreach);
> >  
> >  use PMG::pmgcfg;
> >  use PMG::AtomicFile;
> > @@ -306,8 +306,33 @@ sub pmg_restore {
> >  	    unlink "$dirname/config/etc/pmg/cluster.conf"; # never restore cluster config
> >  	    rmtree "$dirname/config/etc/pmg/master";
> >  
> > -	    # remove current config, but keep directory for INotify
> > -	    rmtree("/etc/pmg", { keep_root => 1 });
> > +	    # remove current config, but keep directories for INotify
> > +	    my $keep_dirs = {
> > +		acme => { accounts => 1 },
> > +		dkim => 1,
> > +		pbs => 1,
> > +		};
> 
> Style nit: indentation
> 
> I wonder if we should have a helper for removing only files (or
> alternatively keeping all directories) from a directory structure,
> rather than passing explicitly what to keep? Otherwise, this list needs
> to be updated when the directory structure changes.
was one of my ideas, but then I thought it would be a larger change - from
the current behavior and leave potentially unrelated, manually created
directories lying around.
Then again - you have a point with a few directory-leftovers being
preferable to manually tracking (and likely forgetting) added
config-directories in an additional place - I'll try to add
`rmtree_keep_skel` to PVE::Utils, and use it here


> 
> Also might make sense to put it somewhere more central, as it likely
> will be needed when PVE gets host backup/restore support (for PBS) too?
> But can still be done when actually needed of course.
> 
> > +
> > +	    my $remove_with_exclude;
> > +	    $remove_with_exclude = sub {
> > +		my ($dir, $excl) = @_;
> > +		dir_glob_foreach($dir, '.*', sub {
> > +		    my ($fn) = @_;
> > +		    return if $fn eq '.';
> > +		    return if $fn eq '..';
> > +		    if ( my $e = $excl->{$fn}) {
> > +			if (ref($e)) {
> > +			    $remove_with_exclude->("$dir/$fn", $e);
> > +			} else {
> > +			    rmtree("$dir/$fn", { keep_root => 1});
> > +			}
> > +		    } else {
> > +			rmtree("$dir/$fn");
> > +		    }
> > +		});
> > +	    };
> > +	    $remove_with_exclude->('/etc/pmg', $keep_dirs);
> > +
> >  	    # copy files
> >  	    system("cp -a $dirname/config/etc/pmg/* /etc/pmg/") == 0 ||
> >  		die "unable to restore system configuration: ERROR";