Static/Dynamic Inventory generation tool to see how they scale

generate_inventory.py

#!/usr/bin/env python

'''
Example custom dynamic inventory script for Ansible, in Python.
'''

import os
import sys
import argparse
from jinja2 import Template

INVENTORY_STRUCTURE = """
{%- for groupname in inventory -%}
{%- if groupname != '_meta' -%}
[{{ groupname }}]
{% for host in inventory[groupname]['hosts'] -%}
{{ host }} ip={{inventory['_meta'][host]['ip']}} ansible_connection=local
{% endfor -%}

[{{ groupname }}:vars]
{% for key,value in inventory[groupname]['vars'].items() -%}
{{ key }}={{ value }}
{% endfor %}

{%- endif -%}
{%- endfor -%}
"""

# Generator
def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('--generate', action = 'store_true')
    parser.add_argument('-g','--group',action='append',nargs=3,
        metavar=('group_name','number_of_nodes','number_of_group_vars'),help='help:')
    parser.add_argument('--hostvars', action = 'store')
    parser.add_argument('--list', action = 'store_true')
    parser.add_argument('--host', action = 'store')
    args = parser.parse_args()
    if args.generate or args.group:
        if args.group is None:
            group = [['groupa','10','1'],['groupb','5','1']]
        else:
            group = args.group
        inventory = generate(group)
        with open('inventory_dict', 'w') as invf:
            invf.write(str(inventory))
        print(inventory)
        with open('inventory','w') as static_inv:
            t = Template(INVENTORY_STRUCTURE)
            content = t.render(inventory=inventory)
            print(content)
            static_inv.write(content)

    if args.list:
        with open('inventory_dict', 'r') as inv:
            inventory = inv.read()
            print(inventory)
    if args.host:
        # meta optimisation is in use, and therefore host shouldn't be callsed
        print("{}")

def generate(group):
    inventory = dict()
    hostvars = dict()
    total_nodes = 0
    for groupname, amount_of_nodes, amount_of_group_vars in group:
        amount_of_nodes = int(amount_of_nodes)
        amount_of_group_vars = int(amount_of_group_vars)
        inventory[groupname] = dict()
        inventory[groupname]['hosts'] = [ 'host{}'.format(x) for x in range(total_nodes,total_nodes + amount_of_nodes)]
        inventory[groupname]['vars'] = { 'variable' + str(x): str(x) for x in xrange(0, amount_of_group_vars) }
        total_nodes += amount_of_nodes
    # optimisation with meta
    for i in xrange(0, total_nodes):
        hostname = 'host' + str(i)
        hostvars[hostname] = { 'ip': str(i) }
    inventory['_meta'] = hostvars
    return inventory

main()