Take a JSON file. Something like this:

1. cat /etc/facter/facts.d/keystores.json
   

   {
           "keystores": [{
                   "file1.jks": {
                           "foo_root_ca_v1": {
                                   "remaining_days": 5324,
                                   "owner": "CN=FOO, O=BAR, C=SE",
                                   "issuer": "CN=FOO Root CA v1, O=BAR, C=SE" 
                           }
                   }
           }]
   }
   

This will result in a JSON string via an API call to https://foreman.domain.com/api/v2/hosts/:host_id/facts?search=keystores:

{
  "total": 374,
  "subtotal": 1,
  "page": 1,
  "per_page": 200,
  "search": "keystores host = 62",
  "sort": {
    "by": null,
    "order": null
  },
  "results": {"foo.domain.com":{"keystores":"[{\"file1.jks\"=>{\"foo_root_ca_v1\"=>{\"issuer\"=>\"CN=FOO Root CA v1, O=BAR, C=SE\", \"owner\"=>\"CN=FOO, O=BAR, C=SE\", \"remaining_days\"=>5324}}}]"}}
}

The keystores hash should not be stringified. This fact, it should be noted, will work fine in Puppet. I'm guessing the POST request to Foreman, when uploading the fact, is stringifying everything after the facter variable.

To test this facter variable on Puppet, run "puppet apply" on the following code:

$file = $::keystores[0]['file1.jks']["foo_root_ca_v1"]["remaining_days"]
notice "$file"