datatest.cf

body common control
{
    bundlesequence => { "datatest" };
}
body agent control
{
    ifelapsed => 0;
}
bundle agent datatest
{
vars:
    "data_with_list_of_strings" data => parsejson('{"key":["item1","item2"]}');
    "data_with_list_of_maps" data => parsejson('{"key":[{"name":"item1"},{"name":"item2"}]}');

methods:
    "handle_list_of_strings" usebundle => handle_list_of_strings(@(data_with_list_of_strings[key]));
    "handle_list_of_maps" usebundle => handle_list_of_maps(@(data_with_list_of_maps[key]));
}

bundle agent handle_list_of_strings(list)
{
vars:
    "list_str" string => format("%S", list);

methods:
    # Bundle is applied for each item in the list
    "handle_list_items" usebundle => handle_string_item($(list));

reports:
    "$(this.bundle) called with list $(list_str)";
}

bundle agent handle_list_of_maps(list)
{
vars:
    "list_str" string => format("%S", list);

methods:
    # Bundle is not applied for each item in the list
    "handle_list_items" usebundle => handle_map_item($(list));

reports:
    "$(this.bundle) called with list $(list_str)";
}

bundle agent handle_string_item(item)
{
reports:
    "$(this.bundle) called with item $(item)";
}

bundle agent handle_map_item(item)
{
vars:
    "item_str" string => format("%S", item);

methods:
    "handle_string_item" usebundle => handle_string_item($(item[name]));

reports:
    "$(this.bundle) called with item $(item_str)";
}

(13:21:35)(tj@ganga)(~)$ cf-agent --version
CFEngine Core 3.8.0b1
(13:21:40)(tj@ganga)(~)$ cf-agent /tmp/datatest.cf 
R: handle_string_item called with item item1
R: handle_string_item called with item item2
R: handle_list_of_strings called with list ["item1","item2"]
R: handle_list_of_maps called with list [{"name":"item1"},{"name":"item2"}]
(13:21:43)(tj@ganga)(~)$