---
name: "Config::Model::BackendTrackOrder"
section: "3pm"
platform: "linux"
package: "libconfig-model-perl"
version: "2.155-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Config::Model::BackendTrackOrder"
---

# Config::Model::BackendTrackOrder(3pm)

Track read order of elements from configuration

## NAME

Config::Model::BackendTrackOrder - Track read order of elements from configuration

## VERSION

version 2.155

## SYNOPSIS

```
 # inside a backend
 use Config::Model::BackendTrackOrder;
 has tracker => (
    is => 'ro',
    isa => 'Config::Model::BackendTrackOrder',
    lazy_build => 1,
 );
 sub _build_tracker {
    my $self = shift;
    return Config::Model::BackendTrackOrder->new(
        backend_obj => $self,
        node => $self->node,
    ) ;
 }
 # register elements to record user order
 $self->tracker->register_element('foo');
 $self->tracker->register_element('bar');
 # later, when writing data back
 foreach my $elt ( $self->tracker->get_ordered_element_names ) {
      # write data
 }
```

## DESCRIPTION

This module is used by backends to record the order of the configuration elements found in user file. Later these elements can be written back in the file using the same order.

Data are written in canonical order if `"canonical"` method of the "Config::Model::Instance" in instance returns true.

## CONSTRUCTOR

THe constructor accepts the following parameters:

- backend\_obj

  The backend object holding this tracker (required).

- node

  The node holding the backend above

## METHODS

### register\_element

Register the element and keep track of the registration order during initial load

Element registered after initial load (i.e . user modification) are registered using canonical order.

### get\_ordered\_element\_names

Returns a list of elements respecting user's order.

Returns the canonical list if Instance canonical attribute is 1.

## AUTHOR

Dominique Dumont

## COPYRIGHT AND LICENSE

This software is Copyright (c) 2005-2022 by Dominique Dumont.

This is free software, licensed under:

```
  The GNU Lesser General Public License, Version 2.1, February 1999
```