python - AWS | Syntax error in module': invalid syntax

Question

I have created python script which is uploaded as a zip file in AWS Lambda function with stompy libraries bundled in them.

Logs for python 2.7:-

Response:
null

Request ID:
"c334839f-ee46-11e8-8970-612f1dc92e41"

Function Logs:
START RequestId: c334839f-ee46-11e8-8970-612f1dc92e41 Version: $LATEST
CONNECTION Started
CONNECTION established
CONNECTION Subscribed
[WARNING]   2018-11-22T11:07:12.798Z    c334839f-ee46-11e8-8970-612f1dc92e41    Unknown response frame type: '' (frame length was 3)
END RequestId: c334839f-ee46-11e8-8970-612f1dc92e41
REPORT RequestId: c334839f-ee46-11e8-8970-612f1dc92e41  Duration: 10027.75 ms   Billed Duration: 10100 ms   Memory Size: 128 MB Max Memory Used: 30 MB

My Code:-

import time
import boto3
import stomp

kinesis_client = boto3.client('kinesis')


class Listener(stomp.ConnectionListener):
    msg_list = []
    def on_error(self, headers, message):
        print('received an error "%s"' % message)

    def on_message(self, headers, message):
        print('received a message "%s"' % message)
        kinesis_client.put_record(
            StreamName='Purchasing',
            Data=u'{}
'.format(message).encode('utf-8'),
            PartitionKey='0'
        )


def lambda_handler(event, context):
    conn = stomp.Connection(host_and_ports=[('b-4714-4441-8166-47aae158281a-1.mq.eu-central-1.amazonaws.com', 8162)])
    lst = Listener()
    conn.set_listener('Listener', Listener())
    conn.start()
    conn.connect(login='test_mq', passcode='test_mq')
    conn.subscribe(destination='/queue/Purchasing', id='b-4714-4441-8166-47aae158281a', ack='auto')
    message = lst.msg_list
    print('Waiting for messages "%s"' % message)
    time.sleep(10)
    conn.disconnect()
    return ''

I am not sure why my message is not showing up in my output,instead it always shows up "Response: null".

Answer 1

EDIT: As pointed by @Petesh, the issue comes from stompy(external library), which hasn't been ported to Python3.

If you check the source code, you can find this:

except socket.timeout, exc:

which is invalid syntax for python3+

If you run your Lambdas in python3.6/3.7 environment, the syntax is invalid.

The issue might go away if you choose python 2.7, but you will also have to adjust your code, libraries, etc.