NAME

       Rex::CMDB::YAML - YAML-based CMDB provider for Rex

DESCRIPTION

       This module collects and merges data from a set of YAML files to provide configuration
       management database for Rex.

SYNOPSIS

        use Rex::CMDB;

        set cmdb => {
          type           => 'YAML',
          path           => [ 'cmdb/{hostname}.yml', 'cmdb/default.yml', ],
          merge_behavior => 'LEFT_PRECEDENT',
        };

        task 'prepare', 'server1', sub {
          my %all_information          = get cmdb;
          my $specific_item            = get cmdb('item');
          my $specific_item_for_server = get cmdb( 'item', 'server' );
        };

CONFIGURATION AND ENVIRONMENT

   path
       The path used to look for CMDB files. It supports various use cases depending on the type
       of data passed to it.

       •   Scalar

            set cmdb => {
              type => 'YAML',
              path => 'path/to/cmdb',
            };

           If a scalar is used, it tries to look up a few files under the given path:

            path/to/cmdb/{environment}/{hostname}.yml
            path/to/cmdb/{environment}/default.yml
            path/to/cmdb/{hostname}.yml
            path/to/cmdb/default.yml

       •   Array reference

            set cmdb => {
              type => 'YAML',
              path => [ 'cmdb/{hostname}.yml', 'cmdb/default.yml', ],
            };

           If an array reference is used, it tries to look up the mentioned files in the given
           order.

       •   Code reference

            set cmdb => {
              type => 'YAML',
              path => sub {
                my ( $provider, $item, $server ) = @_;
                my @files = ( "$server.yml", "$item.yml" );
                return @files;
              },
            };

           If a code reference is passed, it should return a list of files that would be looked
           up in the same order. The code reference gets the CMDB provider instance, the item,
           and the server as parameters.

       When the 0.51 feature flag or later is used, the default value of the "path" option is:

        [qw(
          cmdb/{operatingsystem}/{hostname}.yml
          cmdb/{operatingsystem}/default.yml
          cmdb/{environment}/{hostname}.yml
          cmdb/{environment}/default.yml
          cmdb/{hostname}.yml
          cmdb/default.yml
        )]

       The path specification supports macros enclosed within curly braces, which are dynamically
       expanded during runtime. By default, the valid macros are Rex::Hardware variables,
       "{server}" for the server name of the current connection, and "{environment}" for the
       current environment.

       Please note that the default environment is, well, "default".

       You can define additional CMDB paths via the "-O" command line option by using a
       semicolon-separated list of "cmdb_path=$path" key-value pairs:

        rex -O 'cmdb_path=cmdb/{domain}.yml;cmdb_path=cmdb/{domain}/{hostname}.yml;' taskname

       Those additional paths will be prepended to the current list of CMDB paths (so the last
       one specified will get on top, and thus checked first).

   merge_behavior
       This CMDB provider looks up the specified files in order, and returns the requested data.
       If multiple files specify the same data for a given item, then the first instance of the
       data will be returned by default.

       Rex uses Hash::Merge internally to merge the data found on different levels of the CMDB
       hierarchy. Any merge strategy supported by that module can be specified to override the
       default one. For example one of the built-in strategies:

        set cmdb => {
          type           => 'YAML',
          path           => 'cmdb',
          merge_behavior => 'LEFT_PRECEDENT',
        };

       Or even custom ones:

        set cmdb => {
          type           => 'YAML',
          path           => 'cmdb',
          merge_behavior => {
            SCALAR => sub {},
            ARRAY  => sub {},
            HASH   => sub {},
        };

       For the full list of options, please see the documentation of Hash::Merge.