Porting to aws-cdk ( in python ).

I have been attempting to port this chat-app to a aws-cdk application, and feel like i’m close, but not quite there yet.

This is the response i’m getting `[ec2-user@ip-172-31-x-x websocket]$ wscat -c wss://xxxxxxx.execute-api.ap-southeast-2.amazonaws.com/prod Connected (press CTRL+C to quit)

{“action”:“sendmessage”,“data”:“hello world”} < {“message”: “Internal server error”, “connectionId”:“VNRUSeldSwMCIRQ=”, “requestId”:“VNRXVFJOywMF3-Q=”}`

I know that the message is arriving at the lambda associated with the sendmessage lambda. I’m able to to print it and see it in the lambda logs. I’m getting a client error when it trys to post_connection.

ERROR] EndpointConnectionError: Could not connect to the endpoint URL: "https://execute-api.ap-southeast-2.amazonaws.com/@connections/VNmugd9KSwMCFwQ%3D"

I have attempted to reduce my lambda down to a simple as seems sensible. Just to try and diganose the issue, i also gave the lambda function full administrative permissions, but that made no difference either.

Heres the labmda code.

import boto3
import os
from botocore.exceptions import ClientError
import json
def lambda_handler(event, context):
    message = 'one two three'.encode('utf-8')
    body = event['body']
    print(body)
    connectionId = event['requestContext']['connectionId']
    print(connectionId)
    api_client = boto3.client('apigatewaymanagementapi')
    api_client.post_to_connection(
            Data = message,
            ConnectionId = connectionId
    )
    return {    
            'statusCode': 200, 
            'body': 'Message Sent' 
    }

[tuanardouin]

I’m also trying to use websocket with CDK. Your code helped me a lot !

I created this repository if you want :

https://github.com/tuanardouin/WebSocket-CDK

[mrpackethead]

There is a bug / error in the Boto3 documentation!!! The boto3 client docs dont’ say how to specifiy the url! I foudn this issue in the boto github issues, its been an issue for nearly 2 years with multiple people hitting the same issue! Minor change to the lambda…

My problem is resolved.

import boto3
import os
from botocore.exceptions import ClientError
import json


def lambda_handler(event, context):

    message = 'one two three'
    print(event)
    
    connectionId = event['requestContext']['connectionId']
    print(connectionId)
    
    url = 'https://' + event['requestContext']['domainName'] + '/prod'
    
    api_client = boto3.client('apigatewaymanagementapi', endpoint_url=url)
    api_client.post_to_connection(
            Data = message,
            ConnectionId = connectionId
    )

    return {    
            'statusCode': 200, 
            'body': 'Message Sent' 
    }```