JSON containers improve CFEngine and EFL

CFEngine 3.6 will be able to parse JSON files making EFL data files more readable.

The current data format of the Evolve Free Promise Library is CSV. CSV files are workable but, become error prone when record lines become long. In the following example, run using a build from the CFEngine 3.6 source code, the init bundle creates a data file that we normally maintain by other means. It exists here for convenience.

The bundle sysctl loads the JSON, indexes it, then iterates through it. This is similar to how EFL uses the function CFEngine readstringarrayidx. Imagine a record with many fields, that line wrap around your screen in CSV form. In JSON format the same data is more readable.

body common control
{
        bundlesequence => { "main", };
}

bundle agent main
{
        methods:
                "any" usebundle => init;
                "any" usebundle => sysctl( "/tmp/sysctl.json" );
}

bundle agent init 
{
        vars:
                "sysctl" string => '
[
    {
        "context": "any",
        "name": "net.ipv6.conf.all.accept_ra",
        "value": 0,
        "promisee": "IPV6 Team"
    },
    {
        "context": "any",
        "name": "net.ipv6.conf.default.autoconf",
        "value": 0,
        "promisee": "IPV6 Team"
    }
]
';
   files:
      "/tmp/sysctl.json"
         edit_defaults => empty,
         create        => 'true',
         edit_line     => el_init( "${sysctl}" );
}

body edit_defaults empty
{
   empty_file_before_editing => "true";
   edit_backup               => "false";
}

bundle edit_line el_init( str )
{
   insert_lines:
      "${str}";
}

bundle agent sysctl( ref )
{
   vars:
      "sysctl"
         comment => "Read json file into container",
# New vars type 'data'.
         data    => readjson( "${ref}", 1024 );

      "i"
         comment => "Get index of json for iteration",
         slist   => getindices( "sysctl" );

   reports:
      "
context  => ${sysctl[${i}][context]}
name     => ${sysctl[${i}][name]}
value    => ${sysctl[${i}][value]}
promisee => ${sysctl[${i}][promisee]}
";
}

$ cf-agent -f ./json.cf
2013-11-27T13:48:04-0500   notice: /main/methods/'any'/sysctl: R: 
context  => any
name     => net.ipv6.conf.all.accept_ra
value    => 0
promisee => IPV6 Team

2013-11-27T13:48:04-0500   notice: /main/methods/'any'/sysctl: R: 
context  => any
name     => net.ipv6.conf.default.autoconf
value    => 0
promisee => IPV6 Team