doc: comment public methods

also fix best practice

lib/Ravada/Auth.pm

@@ -100,7 +100,7 @@ sub login_external {
             return $login_ok;
         }
     }
-    return undef;
+    return;
 }
 
 =head2 enable_LDAP

lib/Ravada/Auth/SQL.pm

@@ -961,6 +961,12 @@ sub list_all_permissions($self) {
     return @list2;
 }
 
+=head2 grant_type
+
+Returns the type of a grant type, currently it can be 'boolaean' or 'int'
+
+=cut
+
 sub grant_type($self, $permission) {
     return 'boolean' if !exists $self->{_grant_type}->{$permission};
     return $self->{_grant_type}->{$permission};
@@ -1129,6 +1135,14 @@ sub grants($self) {
     return %{$self->{_grant}};
 }
 
+=head2 grants_info
+
+Returns a list of the permissions granted to an user as a hash.
+Each entry is a reference to a list where the first value is
+the grant and the second the type
+
+=cut
+
 sub grants_info($self) {
     my %grants = $self->grants();
     my %grants_info;

lib/Ravada/Domain.pm

@@ -706,7 +706,7 @@ sub _around_add_volume {
         confess "Error: volume $name already exists"
             if grep {$_->info->{name} eq $name} $self->list_volumes_info;
     }
-    confess "Error: target $args{target} already exists"
+    confess "Error: target $args{target} already exists in domain ".$self->name
             if grep {$_->info->{target} eq $args{target} } $self->list_volumes_info;
 
     my $ok = $self->$orig(%args);

lib/Ravada/Front.pm

@@ -1343,6 +1343,16 @@ sub settings_global($self) {
     return $self->_get_settings();
 }
 
+=head2 setting
+
+Sets or gets a global setting parameter
+
+    $rvd_front->('debug')
+
+Settings are defined and stored in the table settings in the database.
+
+=cut
+
 sub setting($self, $name, $new_value=undef) {
 
     confess "Error: wrong new value '$new_value' for $name"
@@ -1393,6 +1403,15 @@ sub _settings_by_id($self) {
     return $orig_settings;
 }
 
+=head2 feature
+
+Returns if a feature is available
+
+  if ($rvd_front->$feature('ldap')) {
+     ....
+
+=cut
+
 sub feature($self,$name=undef) {
     if (!defined $name) {
         my $feature;