CFEngine: new sort(), reverse(), shuffle() functions
  2013-05-27

These slist functions will be part of the upcoming 3.5 release. For each function, a small downloadable example:

Sort

Sort slist elements, at the moment only lexicographical sort is supported (“lex” argument):

sort.cf

body common control {
  bundlesequence => { "my_sort" };
}

bundle agent my_sort {

  vars:
    "countries"     slist   =>  {
                                  "bulgaria",
                                  "cambodia",
                                  "malaysia",
                                  "australia",
                                  "canada"
                                };

    "countries_sorted" slist  => sort("countries", "lex");

    # Slist to string for reports
    "countries_str"         string =>  join (" ", "countries");
    "countries_sorted_str"  string =>  join (" ", "countries_sorted");

  reports:
    "Countries:        $(countries_str)";
    "Sorted countries: $(countries_sorted_str)";
}

Output: 

$ cf-agent -KIf sort.cf
2013-05-27T20:09:57+0200   notice: R: Countries:        bulgaria cambodia malaysia australia canada
2013-05-27T20:09:57+0200   notice: R: Sorted countries: australia bulgaria cambodia canada malaysia

Reverse

Reverse the order of slist elements:

reverse.cf

body common control {
  bundlesequence => { "my_reverse" };
}

bundle agent my_reverse {

  vars:
    "countries"     slist   =>  {
                                  "australia",
                                  "bulgaria",
                                  "cambodia",
                                  "canada",
                                  "malaysia"
                                };

    "countries_reversed" slist  =>  reverse("countries");

    # Slist to string for reports
    "countries_str"           string =>  join (" ", "countries");
    "countries_reversed_str"  string =>  join (" ", "countries_reversed");

  reports:
    "Countries:          $(countries_str)";
    "Reversed countries: $(countries_reversed_str)";
}

Output: 

$ cf-agent -KIf reverse.cf
2013-05-27T20:02:30+0200   notice: R: Countries:          australia bulgaria cambodia canada malaysia
2013-05-27T20:02:30+0200   notice: R: Reversed countries: malaysia canada cambodia bulgaria australia

Shuffle

Shuffle slist elements, given a random seed:

shuffle.cf

body common control {
  bundlesequence => { "my_shuffle" };
}

bundle agent my_shuffle {

  vars:
    "countries"     slist   =>  {
                                  "australia",
                                  "bulgaria",
                                  "cambodia",
                                  "canada",
                                  "malaysia"
                                };

    "countries_shuffled_0" slist  =>  shuffle("countries", "my seed");
    "countries_shuffled_1" slist  =>  shuffle("countries", "another seed");

    # Slist to string for reports
    "countries_str"            string =>  join (" ", "countries");
    "countries_shuffled0_str"  string =>  join (" ", "countries_shuffled_0");
    "countries_shuffled1_str"  string =>  join (" ", "countries_shuffled_1");

  reports:
    "Countries:            $(countries_str)";
    "Shuffled countries 0: $(countries_shuffled0_str)";
    "Shuffled countries 1: $(countries_shuffled1_str)";
}

Output: 

$ cf-agent -KIf shuffle.cf
2013-05-27T20:17:16+0200   notice: R: Countries:            australia bulgaria cambodia canada malaysia
2013-05-27T20:17:16+0200   notice: R: Shuffled countries 0: cambodia bulgaria malaysia australia canada
2013-05-27T20:17:16+0200   notice: R: Shuffled countries 1: canada malaysia australia bulgaria cambodia