Stephen's Work Ramblings

The new LCFG profile framework makes it simple to retrieve component and resource information from profiles stored in the various standard formats (XML, Berkeley DB and status files).

Loading a profile from XML, DB or status directory:

my $p = LCFG::Profile->new_from_xml(“example.xml”);

my $p = LCFG::Profile->new_from_bdb(“example.db”);

my $p = LCFG::Profile->new_from_status_dir(“/run/lcfg/status”);

Loading a component from a DB or status file:

my $c = LCFG::Profile::Component->new_from_bdb( “example.bdb”, “client” );

my $c = LCFG::Profile::Component->new_from_statusfile( “/run/lcfg/status/client” );

Retrieving a component (e.g. client) from the profile:

my $c = $p->find_component(“client”);

Retrieving a resource (e.g. client.components) from a component:

my $r = $c->find_resource(“components”);

Getting the resource value:

say $r->value;

For convenience, if the resource is a tag list then you can get the value as a perl list:

@comps = $r->value;
for my $comp (@comps) {
…
}

Over the last few months the new libraries for handling LCFG profiles have been shaping up nicely. They are finally reaching a point where they match up with my original aims so I thought I’d give a taste of how it all works. Here’s an example of processing an LCFG XML profile into the Berkeley DB and rpmcfg files required by the client:

use LCFG::Profile;

my $xml    = '/var/lcfg/conf/profile/xml/example.lcfg.org.xml';
my $dbm    = '/tmp/example.lcfg.org.DB2.db';
my $dbm_ns = 'example';
my $rpmcfg = '/tmp/example.lcfg.org.rpmcfg';

my $new_profile = LCFG::Profile->new_from_xml($xml);

my $update_dbm = 0;
if ( -f $dbm ) {
    my $cur_profile = LCFG::Profile->new_from_bdb($dbm);

    my $diff = $cur_profile->diff($new_profile);

    if ( $diff->size > 0 ) {
        $update_dbm = 1;
    }
} else {
    $update_dbm = 1;
}

if ( $update_dbm ) {
    $new_profile->to_bdb( $dbm, $dbm_ns );
    say 'Updated DBM';
}

my $pkgs_changed = $new_profile->to_rpmcfg($rpmcfg);
if ( $pkgs_changed ) {
    say 'Updated packages';
}

This is basically what the LCFG client does whenever it processes a new profile but is a lot nicer than the current rdxprof code!