Can't use ansible inventory file because it is executable

Question

I am trying to run an Ansible inventory file ansible -i hosts-prod all -u root -m ping and it is failing with this message:

ERROR: The file host         


        

Answer 1

Executable inventories are parsed as JSON instead of ini files, so you can convert it to a script that outputs JSON. On top of that, Ansible passes some arguments to them to a simple 'cat' isn't enough:

#!/bin/bash
cat <<EOF
{
 "_meta": {
   "hostvars": {
     "host1": { "some_var": "value" }
   }
 },
 "hostgroup1": [
   "host1",
   "host2"
 ]
 ...
}
EOF

Not as elegant as a simple 'cat', but should work.

Answer 2

@hkariti's answer is first and closest to the original question. I ended up re-writing the config file entirely into a Ruby script and that is working fine. I thought I'd share that code here since finding complete examples for Ansible dynamic inventory files wasn't super easy for me. The file is different from a static file in how you associate variables with machine listings in the inventory (using the _meta tag)..

#!/usr/bin/env ruby
# this file must be executable (chmod +x) in order for ansible to use it
require 'json'
module LT
  module Ansible
    def self.staging_inventory
      {
        local: {
          hosts:["127.0.0.1"],
          vars: { 
            ansible_connection: "local"
          }
        },
        common: {
          hosts: [],
          children: ["web", "db"],
          vars: {
            ansible_connection: "ssh",
          }
        },
        web: {
          hosts: [],
          children: ["web_staging"]
        },
        db: {
          hosts: [],
          children: ["db_staging"]
        },
        web_staging: {
          hosts: ["webdb01-ci"],
          vars: {
            # server specific vars here
          }
        },
        db_staging: {
          hosts: ["webdb01-ci"]
        }
      }
    end
  end
end
# ansible will pass "--list" to this file when run from command line
# testing for --list should let us require this file in code libraries as well
if ARGV.find_index("--list") then
  puts LT::Ansible::staging_inventory.to_json
end