def get_aws_ec2_metadata_token()

in src/watchdog/__init__.py [0:0]

• 35 lines of code
• 10 McCabe index (conditional complexity)

def get_aws_ec2_metadata_token(timeout=DEFAULT_TIMEOUT):
    # Normally the session token is fetched within 10ms, setting a timeout of 50ms here to abort the request
    # and return None if the token has not returned within 50ms
    try:
        opener = build_opener(HTTPHandler)
        request = Request(INSTANCE_METADATA_TOKEN_URL)
        request.add_header("X-aws-ec2-metadata-token-ttl-seconds", "21600")
        request.get_method = lambda: "PUT"
        try:
            res = opener.open(request, timeout=timeout)
            return res.read()
        except socket.timeout:
            exception_message = "Timeout when getting the aws ec2 metadata token"
        except HTTPError as e:
            exception_message = "Failed to fetch token due to %s" % e
        except Exception as e:
            exception_message = (
                "Unknown error when fetching aws ec2 metadata token, %s" % e
            )
        logging.debug(exception_message)
        return None
    except NameError:
        headers = {"X-aws-ec2-metadata-token-ttl-seconds": "21600"}
        req = Request(INSTANCE_METADATA_TOKEN_URL, headers=headers, method="PUT")
        try:
            res = urlopen(req, timeout=timeout)
            return res.read()
        except socket.timeout:
            exception_message = "Timeout when getting the aws ec2 metadata token"
        except HTTPError as e:
            exception_message = "Failed to fetch token due to %s" % e
        except Exception as e:
            exception_message = (
                "Unknown error when fetching aws ec2 metadata token, %s" % e
            )
        logging.debug(exception_message)
        return None