ansible jsonnet proof of concept

00_ansible_jsonnet.md

# ansible all -i inventory.sh -m debug -a var=host_specific_var

host-a | SUCCESS => {
    "host_specific_var": "abcde-a"
}
host-b | SUCCESS => {
    "host_specific_var": "abcde-b"
}
host-c | SUCCESS => {
    "host_specific_var": "abcde-c"
}

inventory.jsonnet

#!/usr/bin/jsonnet
local host_specific_var = 'abcde';

{
  jsonnet_hosts: {
    hosts: [
      'host-a',
      'host-b',
      'host-c',
    ],
    vars: {
      common_var: 'host01-host02',
    },
  },
  _meta: {
    hostvars: {
      [x]: {
        host_specific_var: host_specific_var + '-' + std.split(x, '-')[1],
      }
      for x in $.jsonnet_hosts.hosts
    },
  },
}

inventory.sh

#!/bin/sh

dynamic_json_file=inventory.jsonnet
if [ "$1" == "--list" ] ; then
    jsonnet ${dynamic_json_file}
elif [ "$1" == "--host" ]; then
    echo '{"_meta": {"hostvars": {}}}'
else
    echo "{ }"
fi