Intermittent Issues Opening websocket on AWS ECS

Question

Running my Golang app using gorilla websockets in AWS ECS using Fargate and an ALB in front. A couple days ago connecting to the socket was working and then would intermittently fail. Now it is consistently failing to open the socket.

I've tried connecting through the ALB with and without the port as well as connecting to the public ip the ECS Task is running on.

The error my app is logging: websocket: the client is not using the websocket protocol: 'upgrade' token not found in 'Connection' header

Headers that my app receives, the connection header is somehow missing by the time my app handles the request

{
        "Sec-Websocket-Extensions": [
            "permessage-deflate; client_max_window_bits"
        ],
        "Sec-Websocket-Key": [
            "Dlb3vf23t9rtkY+wwazr7w=="
        ],
        "Sec-Websocket-Version": [
            "13"
        ],
        "Via": [
            "1.1 ::ffff:172.20.32.1 (Mikrotik HttpProxy)"
        ],
        "X-Forwarded-Port": [
            "80"
        ],
        "X-Forwarded-Proto": [
            "http"
        ],
        "X-Proxy-Id": [
            "619378727"
        ]
    }

Ways I've tried to connect:

wscat -nc ws://www.example.com/v1/ws

wscat -nc ws://www.example.com:80/v1/ws

wscat -nc ws:///v1/ws

wscat -nc ws://:80/v1/ws

Answer

Hello,

The shared error is related to wrong nginx configurations, which is out of scope of AWS premium support but I have shared the below links and information on best effort basis.

This issue seems to be related with the issue in nginx configurations, I could find some links where the same issue have been discussed you can check your configurations and what is missing.

https://stackoverflow.com/questions/65309160/client-is-not-using-the-websocket-protocol-upgrade-token-not-found-in-connec

https://stackoverflow.com/questions/74509802/websocket-the-client-is-not-using-the-websocket-protocol-upgrade-token-not-f

https://forum.mattermost.com/t/websocket-connect-err-error-websocket-the-client-is-not-using-the-websocket-protocol-upgrade-token-not-found-in-connection/9110

https://stackoverflow.com/questions/70210654/httpd-websocket-error-upgrade-token-not-found-in-connection-header

Have a great day ahead !

Intermittent Issues Opening websocket on AWS ECS

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