Ansible hosts files gerneration for AWS EC2 instances

ansible_hosts_from_aws.py

 #!/usr/bin/env python
import sys 
from boto import ec2 

region = 'us-east-1'
region = 'ap-southeast-1'
region = 'ap-south-1'

INSTANCE_STATE_RUNNING = 16

def get_services(conn):
  rs = conn.get_all_instances(filters={"instance-state-code" : INSTANCE_STATE_RUNNING })
  instances = [instance for resource in rs for instance in resource.instances]
  instance_dict = {}
  for instance in instances:
    name = instance.tags.get('Service',None)
    if name is None:
        continue
    name = str(name)
    private_ip_address = str(instance.private_ip_address)
    instance_dict[name] = instance_dict.get(name,[])
    instance_dict[name].insert(0,private_ip_address)
  return instance_dict

def main():
  connection = ec2.connect_to_region(region)
  if connection is None:
      print("Unable to connect to region %s", region)
  with open('hosts', 'w') as the_file:
        services = get_services(connection)
        for service,ips in services.iteritems():
            if len(sys.argv) == 2 and sys.argv[1] == "local":
                the_file.write("[%s]\n" % service)
                the_file.write("localhost ansible_connection=local")
                the_file.write("\n\n\n")
            else:
                if len(ips)  > 0:
                    the_file.write("[%s]\n" % service)
                    the_file.write("\n".join(ips))
                    the_file.write("\n\n\n")

if __name__ == "__main__":
   main()