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39 lines
1.0 KiB
Python

import os
from datetime import datetime
from urllib.request import Request, urlopen
SITE = os.environ['site'] # URL of the site to check, stored in the site environment variable
EXPECTED = os.environ['expected'] # String expected to be on the page, stored in the expected environment variable
def validate(res):
"""
Return False to trigger the canary
Currently this simply checks whether the EXPECTED string is present.
However, you could modify this to perform any number of arbitrary
checks on the contents of SITE.
"""
return EXPECTED in res
def lambda_handler(event, context):
print(f"Checking {SITE} at {event['time']}...")
try:
req = Request(SITE, headers={'User-Agent': 'AWS Lambda'})
if not validate(str(urlopen(req).read())):
raise Exception('Validation failed')
except Exception:
print('Check failed!')
raise
else:
print('Check passed!')
return event['time']
finally:
print(f"Checking complete at {str(datetime.now())}")