import socket
import ssl, boto3
import re,sys,os,datetime

def ssl_expiry_date(domainname='xxx.xxx.xxx.xxx'):
    ssl_date_fmt = r'%b %d %H:%M:%S %Y %Z'
    context = ssl.create_default_context()
    conn = context.wrap_socket(
        socket.socket(socket.AF_INET),
        server_hostname=domainname,
    )
    # 3 second timeout because Lambda has runtime limitations
    conn.settimeout(3.0)
    conn.connect((domainname, 443))
    ssl_info = conn.getpeercert()
    return datetime.datetime.strptime(ssl_info['notAfter'], ssl_date_fmt).date()

def ssl_valid_time_remaining(domainname='xxx.xxx.xxx.xxx'):
    """Number of days left."""
    expires = ssl_expiry_date(domainname='xxx.xxx.xxx.xxx')
    return expires - datetime.datetime.utcnow().date()

def sns_Alert(dName, eDays, sslStatus):
    sslStat = dName + ' SSL certificate will be expired in ' + eDays +' days!! '
    snsSub = dName + ' SSL Certificate Expiry ' + sslStatus + ' alert'
    print(sslStat)
    print (snsSub)
    response = client.publish(
    TargetArn="arn:aws:sns:us-west-2:1111111111:cert_check",
    Message= sslStat,
	Subject= snsSub
	)


#####Main Section
client = boto3.client('sns')
def lambda_handler(event, context):
    f = ['xxx.xxx.xxx.xxx']
    for dName in f:
        expDate = ssl_valid_time_remaining(dName.strip())
        (a, b) = str(expDate).split(',')
        (c, d) = a.split(' ')
        if int(c) < 40:
            sns_Alert(dName, str(c), 'Critical')
        elif int(c) == 60:
            sns_Alert(dName, str(c), 'Warning')
        elif int(c) == 90:
            sns_Alert(dName, str(c), 'Warning')
        else:
            number = '+1777777'
            sns.publish(PhoneNumber = number, Message='cert checker failed' )
            exit()








########## ERROR ###########



{
  "errorMessage": "[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749)",
  "errorType": "SSLError",
  "stackTrace": [
    [
      "/var/task/lambda_function.py",
      40,
      "lambda_handler",
      "expDate = ssl_valid_time_remaining(dName.strip())"
    ],
    [
      "/var/task/lambda_function.py",
      20,
      "ssl_valid_time_remaining",
      "expires = ssl_expiry_date(domainname='35.167.132.157')"
    ],
    [
      "/var/task/lambda_function.py",
      14,
      "ssl_expiry_date",
      "conn.connect((domainname, 443))"
    ],
    [
      "/var/lang/lib/python3.6/ssl.py",
      1093,
      "connect",
      "self._real_connect(addr, False)"
    ],
    [
      "/var/lang/lib/python3.6/ssl.py",
      1084,
      "_real_connect",
      "self.do_handshake()"
    ],
    [
      "/var/lang/lib/python3.6/ssl.py",
      1061,
      "do_handshake",
      "self._sslobj.do_handshake()"
    ],
    [
      "/var/lang/lib/python3.6/ssl.py",
      683,
      "do_handshake",
      "self._sslobj.do_handshake()"
    ]
  ]
}