DynamoDB 触发新的 web 套接字连接时的旧 connectionId

Question

I see in CloudWatch that only sporadically the connectionId of new web socket connections are successfully conveyed by an event, triggered by a new and correct DynamoDB entry...

What I do:

• Connect. From a localhost front-end, I connect to a web socket wss://xxxxxx.execute-api.us-east-1.amazonaws.com/production . A Connect lambda function stores the connectionId each time successfully in a DynamoDB table. This connectiondId varies per connection.
• Trigger. When a new DynamoDB entry is created, an event is sent by a trigger to a Broadcast lambda function. In its current form this Broadcast function (see below) only prints the connectionId which is conveyed in the event (the result is printed in CloudWatch). Here is the problem: This connectionId keeps on being the same, while it should change per new connection... Like there is lazy event cache that should be cleared?
• Disconnect. When at the front-end the web socket connection is ended, a Disconnect lambda function removes the connectionId successfully from the DynamoDB table. I thought: This helps to prevent mixing up connectionIds , but not.

Question: How is it possible the same connectionId is repeatedly printed for different web socket connections? (see attached images) The DynamoDB tables work as expected, and once triggered should convey the correct table entry/value in the event, isn't it?

Side question: Why are some log streams in Cloud Watch clustered and others separate?

Broadcast lambda python code

import json
import boto3

client = boto3.client('apigatewaymanagementapi', endpoint_url="https://xxxxxx.execute-api.us-east-1.amazonaws.com/production")

def lambda_handler(event, context):
    
    # get connectionId from DynamoDB
    print(event['Records'][0]['dynamodb']['Keys']['connectionid']['S'])

CloudWatch logs for different web socket connections

Answer 1

This problem was resolved by filtering INSERT events sent to the Broadcast script. Since also MODIFY and REMOVE events are sent to the script by DynamoDB, once listed as a trigger, and are therefore logged in CloudWatch.

Below code does the job in the Broadcast script

# only look at INSERT dynamodb events and collect connectionId
if record.get('eventName') in ('INSERT'):
    id = record['dynamodb']['Keys']['connectionid']['S']
    print("connectionId: ", id)
else:
    pass