updog/updog.py

from helpers import RepeatedTimer, create_instances, run_check
import sys
import os
import importlib
import inspect
import json

path = os.path.realpath(__file__)
path = path[:path.rfind('/')]

#####################
# Import extensions #
#####################

# Import checkers #
# relative imports suck - https://gideonbrimleaf.github.io/2021/01/26/relative-imports-python.html
sys.path.insert(1, f'{path}/extensions/checkers')

# importlib used to import stuff programmatically, rather than using the hardcoded import keyword, basically the same but it seems it can't import *just* a class
checker_extension_imports = []
for ext_name in os.listdir(f'{path}/extensions/checkers'):
    if ext_name[0] != '.':
        checker_extension_imports.append(f'{ext_name}.{ext_name}')

# checkers contains all the classes for the checker extensions
# e.g. {'CheckerTemplate': checker_template.checker_template.CheckerTemplate}
checkers = {}
for ext in [importlib.import_module(ext) for ext in checker_extension_imports]:
    for name, obj in inspect.getmembers(ext):
        if inspect.isclass(obj):
            checkers[name] = obj

# Import alerts #
# same as above, just for alerts
sys.path.insert(1, f'{path}/extensions/alerts')

alerts_extension_imports = []
for ext_name in os.listdir(f'{path}/extensions/alerts'):
    if ext_name[0] != '.':
        alerts_extension_imports.append(f'{ext_name}.{ext_name}')

# alerts contains all the classes for the checker extensions
# e.g. {'AlertsTemplate': alerts_template.alerts_template.AlertsTemplate}
alerts = {}
for ext in [importlib.import_module(ext) for ext in alerts_extension_imports]:
    for name, obj in inspect.getmembers(ext):
        if inspect.isclass(obj):
            alerts[name] = obj

# Import logging #
# same as above, just for logging
sys.path.insert(1, f'{path}/extensions/logging')

logging_extension_imports = []
for ext_name in os.listdir(f'{path}/extensions/logging'):
    if ext_name[0] != '.':
        logging_extension_imports.append(f'{ext_name}.{ext_name}')

# logging contains all the classes for the checker extensions
# e.g. {'LoggingTemplate': logging_template.logging_template.LoggingTemplate}
logging = {}
for ext in [importlib.import_module(ext) for ext in logging_extension_imports]:
    for name, obj in inspect.getmembers(ext):
        if inspect.isclass(obj):
            logging[name] = obj

# get config from services.json
if 'services.json' in os.listdir(path):
    config_filename = f'{path}/services.json'
elif 'services-example.json' in os.listdir(path):
    config_filename = f'{path}/services-example.json'

with open(config_filename, 'rt') as config_file:
    config_text = ''.join(config_file.readlines())
    # Replace static keywords in config
    keywords = {'%dir%': path}
    for key in keywords:
        config_text = config_text.replace(key, keywords[key])
    config = json.loads(''.join(config_file.readlines()))


instances = create_instances(config, checkers, alerts, logging)
timers = {}

try:
    for service in config.keys():
        if service == 'global-args':
            continue
        timers[service] = RepeatedTimer(config[service]['rate'], run_check,
                                        service, instances[service]['checker'], instances[service]['alerts'], instances[service]['logging'])
except:
    # Stops all RepeatedTimers since they're threaded
    # Doesn't actually stop the threads, just stops repeating it
    for service in timers.keys():
        timers[service].stop()