Gfrktyl

First time moving from Bash to Python for scripting and looking for feedback/improvements. I've spent the weekend learning about OOP, and am aware that not fully utilizing it in this script — so any feedback is much appreciated!

Summary: Python script runs every 5 minutes, confirms server creation/deletion via OpenStack API functioning correctly.

Steps:

1. Check if JSON file exists (this way we can avoid asking for new auth token, as it only expires after 12 hours). If not, get auth token and write to JSON.


2. Read JSON file, ensure auth token hasn't expired.


3. Create a new server.


4. Poll status of server every 5 seconds until 'ACTIVE', or timeout after 2 minutes.


5. Delete server.

I've redacted some code, but should make sense overall. I intend to add logging after more improvements, but back to watching Python-related videos on YouTube for now.

#!/usr/bin/env python3



from datetime import datetime, timedelta

import json

import logging

import os.path

import sys

import time

import requests



OPENSTACK_USER = 'prometheus'

OPENSTACK_PASSWORD = 'REDACTED'

OPENSTACK_PROJECT = 'Prometheus'



SERVER_NAME = 'ServerHealthCheck'

SERVER_FLAVOR = 'e4b7e835-927a-4400-9b89-6e93968f0033'

SERVER_IMAGE = '30fb86b3-31d8-4191-be7d-aacf6c317c3e'



SCRIPT_FILE = os.path.basename(__file__)

STATE_FILE = os.path.splitext(SCRIPT_FILE)[0] + '.json'

LOG_FILE = os.path.splitext(SCRIPT_FILE)[0] + '.log'



logging.basicConfig(filename=LOG_FILE,

                    format='%(asctime)s: %(levelname)s: %(message)s')





def _url(path):

    return 'https://example.org' + path





def token_refresh():

    token_request = requests.post(_url(':5000/v3/auth/tokens'), json={

        'auth': {

            'identity': {

                'methods': ['password'],

                'password': {

                    'user': {

                        'name': OPENSTACK_USER,

                        'domain': {'id': 'default'},

                        'password': OPENSTACK_PASSWORD,

                    }

                }

            },

            'scope': {

                'project': {

                    'domain': {'id': 'default'},

                    'name': OPENSTACK_PROJECT

                }

            }

        }})



    if not token_request.status_code == 201:

        logging.error("Token refresh request returned status code {}n{}n"

                      .format(token_request.status_code, token_request.json()))

        sys.exit(1)



    token = {'token_content': token_request.headers['X-Subject-Token'],

             'token_expires': token_request.json()["token"]["expires_at"]}



    with open(STATE_FILE, 'w') as json_write:

        json.dump(token, json_write)





def server_create():

    create_request = requests.post(_url(':8774/v2.1/servers'), headers=headers, json={

        'server': {

            'name': SERVER_NAME,

            'flavorRef': SERVER_FLAVOR,

            'imageRef': SERVER_IMAGE

        }})



    if not create_request.status_code == 202:

        logging.error("Server create request returned status code {}n{}n"

                      .format(create_request.status_code, create_request.json()))

        sys.exit(1)



    return create_request.json()["server"]["id"]





def server_status(server):

    status_request = requests.get(_url(':8774/v2.1/servers/' + server), headers=headers)

    return status_request.json()["server"]["status"]





def server_delete(server):

    delete_request = requests.delete(_url(':8774/v2.1/servers/' + server), headers=headers)



    if not delete_request.status_code == 204:

        logging.error("Server delete request returned status code {}n{}n"

                      .format(delete_request.status_code, delete_request.json()))

        sys.exit(1)





if __name__ == '__main__':

    # Get new auth token if state file does not exist

    if not os.path.isfile(STATE_FILE):

        token_refresh()



    # Load JSON state file as dictionary

    with open(STATE_FILE, 'r') as f:

        data = json.load(f)



    # Get new auth token if current token expired

    current_gmt = datetime.now() + timedelta(seconds=time.timezone)

    if current_gmt.isoformat() >= data["token_expires"]:

        token_refresh()



    # Set HTTP headers with auth token

    headers = {'X-Auth-Token': data["token_content"],

               'Content-type': 'application/json'}



    # Create new server

    server = server_create()



    # Poll server status

    status = server_status(server)

    request_seconds = 0

    while not status == 'ACTIVE':

        time.sleep(5)

        request_seconds += 5



        if request_seconds >= 120:

            logging.error("Server status {} after 2 minutes".format(status))

            server_delete(server)

            sys.exit(1)



        status = server_status(server)



    # Delete server

    server_delete(server)