Iterate over data container, convert to slist

[olehermanse]

I'd like to iterate over a JSON structure, extracting each value for key "name":

bundle agent __main__
{
  vars:
    "data_container"
      data => '[{"name": "a", "value": "b"},{"name": "c", "value": "d"}]';
    "data_container_index"
      slist => getindices("data_container");
    "data_container_array[$(data_container_index)]"
      string => "$(data_container[$(data_container_index)][name])";
    "data_container_names"
      slist => sort(getvalues(data_container_array), "lex");
}

How can I do the above without using a classic array?

[nickanderson]

I was able to accomplish this without using classic associative arrays using maparray().

https://docs.cfengine.com/docs/3.21/reference-functions-maparray.html

bundle agent __main__
{
  vars:
    "data_container"
      data => '[{"name": "a", "value": "b"},{"name": "c", "value": "d"}]';

    # "data_container_index"
    #   slist => getindices("data_container");
    # "data_container_array[$(data_container_index)]"
    #   string => "$(data_container[$(data_container_index)][name])";

    # Use mapdata() to build a new data container where the keys are the pacakge name
    # We reference back to 'd' because this.k is the positional location in the array returned by packagesmatching()
    "data_container_names" slist => sort( maparray( '$(data_container[$(this.k)][name])', data_container), lex );
}

Variable name                            Variable value                                               Meta tags                                Comment
default:main.data_container              [{"name":"a","value":"b"},{"name":"c","value":"d"}]          source=promise
default:main.data_container_names         {"a","c"}                                                   source=promise

[olehermanse]

Works here too, thanks!

cf-agent -KIf ./test.cf --show-evaluated-vars="default:main"
Variable name                            Variable value                                               Meta tags                                Comment                                 
default:main.data_container              [{"name":"a","value":"b"},{"name":"c","value":"d"}]          source=promise                                                                   
default:main.data_container_names         {"a","c"}                                                   source=promise