Files
cachet-url-monitor/cachet_url_monitor/configuration.py
2016-04-28 01:51:59 -07:00

114 lines
4.0 KiB
Python

#!/usr/bin/env python
import abc
import logging
import requests
import timeit
from yaml import load
class Configuration(object):
"""Represents a configuration file, but it also includes the functionality
of assessing the API and pushing the results to cachet.
"""
def __init__(self, config_file):
#TODO(mtakaki|2016-04-26): Needs validation if the config is correct.
#TODO(mtakaki|2016-04-28): Accept overriding settings using environment
# variables so we have a more docker-friendly approach.
self.config_file = config_file
self.data = load(file(self.config_file, 'r'))
self.expectations = [Expectaction.create(expectation) for expectation
in self.data['endpoint']['expectation']]
def evaluate(self):
#TODO(mtakaki|2016-04-27): Add support to configurable timeout.
try:
self.request = requests.request(self.data['endpoint']['method'],
self.data['endpoint']['url'])
except requests.ConnectionError:
logging.warning('The URL is unreachable: %s %s' %
(self.data['endpoint']['method'],
self.data['endpoint']['url']))
self.status = 3
return
except requests.HTTPError:
logging.exception('Unexpected HTTP response')
self.status = 3
return
except requests.Timeout:
logging.warning('Request timed out')
self.status = 3
return
# We, by default, assume the API is healthy.
self.status = 1
self.message = ''
for expectation in self.expectations:
status = expectation.get_status(self.request)
# The greater the status is, the worse the state of the API is.
if status > self.status:
self.status = status
def push_status_and_metrics(self):
params = {'id': self.data['cachet']['component_id'], 'status':
self.status}
headers = {'X-Cachet-Token': self.data['cachet']['token']}
component_request = requests.put('%s/components/%d' %
(self.data['cachet']['api_url'],
self.data['cachet']['component_id']),
params=params, headers=headers)
if component_request.status_code == 200:
# Successful update
logging.info('Component update: status [%d]' % (self.status,))
else:
# Failed to update the API status
logging.warning('Component update failed with status [%d]: API'
' status: [%d]' % (component_request.status_code, self.status))
class Expectaction(object):
@staticmethod
def create(configuration):
expectations = {
'HTTP_STATUS': HttpStatus,
'LATENCY': Latency
}
return expectations.get(configuration['type'])(configuration)
@abc.abstractmethod
def get_status(self, response):
"""Returns the status of the API, following cachet's component status
documentation: https://docs.cachethq.io/docs/component-statuses
"""
@abc.abstractmethod
def get_message(self, response):
"""Gets the error message."""
class HttpStatus(Expectaction):
def __init__(self, configuration):
self.status = configuration['status']
def get_status(self, response):
if response.status_code == self.status:
return 1
else:
return 3
def get_message(self, response):
return 'Unexpected HTTP status (%s)' % (response.status_code,)
class Latency(Expectaction):
def __init__(self, configuration):
self.threshold = configuration['threshold']
def get_status(self, response):
if response.elapsed.total_seconds() <= self.threshold:
return 1
else:
return 2
def get_message(self, response):
return 'Latency above threshold: %d' % (response.elapsed.total_seconds(),)