ansible module prefix_check

prefix_check.py

DOCUMENTATION = '''
---
module: prefix_check
author: Stanley Kamithi [email protected]
short_description: Check route prefix
description:
    - Inspired by Cumulus Linux prefix_check Ansible Module. \
Given a route prefix, check to see if route exists. \
If the route exists, then do nothing. If route does not exist \
the module will exit with an error.
options:
    prefix:
        description:
            - route to check.
        required: true
    timeout:
        description:
            - timeout interval. if route is not found by the \
time timeout kicks in then exit module
'''

# handy helper for calling system calls.
# calls AnsibleModule.run_command and prints a more appropriate message
# exec_path - path to file to execute, with all its arguments.
#   E.g "/sbin/ip -o link show"
# failure_msg - what message to print on failure
def run_cmd(module, exec_path, failure_msg):
  (rc, out, err) = module.run_command(exec_path)
  if rc == 1:
    module.fail_json(msg=failure_msg)
  return out


def single_route_check_run(module):
  output = run_cmd(module,
      '/sbin/ip route show %s' % (module.prefix),
      '/sbin/ip failed to execute. Check if prog exists')
  # if route is found, output will not be blank
  if len(output.splitlines()) > 0:
    return True
  return False


def check_if_route_exists(module):
  timeout = 0
  # Start loop
  while True:
    # if route is found, return True
    if single_route_check_run(module):
      return True
    # if timeout occurs return False
    elif timeout == module.timeout:
      return False
    # otherwise sleep for poll interval and repeat the test
    else:
      timeout += 1
      time.sleep(module.poll_interval)


def main():
    module = AnsibleModule(
        argument_spec=dict(
            prefix=dict(required=True, type='str'),
            timeout=dict(default=5, type='int'),
        ),
    )

    # define some hardcoded variables
    # polling interval in sec between each ip route show execution
    module.poll_interval = 1

    # function runs a check.
    # If after timeout it will return false
    return_val = check_if_route_exists(module)
    if return_val is True:
        module.exit_json(changed=False, msg="Route Found")
    else:
        module.fail_json(msg="Route not Found. Check Routing Configuration")

# import module snippets
from ansible.module_utils.basic import *
import time

# notice lots of modules don't have this __name__.
# Wonder if its not required?
if __name__ == '__main__':
    main()