Why Does My Heroku Go WebSocket App Generate False Positive H15 Errors on Connection Close?

Heroku H15 Error on WebSocket Close: Understanding the "False Positive"

When utilizing Heroku for hosting a Go service that acts as a WebSocket server, you may encounter the H15 error upon WebSocket connection closure. This error is commonly triggered due to Heroku's router erroneously interpreting the timed-out connection as a high-latency request.

To understand this issue, let's delve into the WebSocket connection establishment process:

1. WebSocket Connection Initiation:

   • The client initiates a WebSocket connection, which initially establishes an HTTP polling connection.
   • Once the connection is upgraded to WebSocket protocol, the client periodically sends heartbeat messages to maintain the connection.

2. Heroku Router Timeout:

   • The Heroku Router sets a timeout of 55 seconds for each request. During the heartbeat period, the router's timeout timer resets.

3. Client Connection Closure:

   • When the client terminates the WebSocket connection (e.g., browser tab closure), the Heroku Router registers the request as being closed.

4. H15 Error Trigger:

   • Due to the previously open and active nature of the WebSocket connection (i.e., heartbeat mechanism), the Heroku Router erroneously classifies it as an "idle" request for the duration of the connection.
   • This mismatch results in the router logging an H15 error, indicating a request that exceeded the timeout limit.

It's important to note that the H15 error often arises from client-initiated WebSocket connection terminations rather than actual runtime issues. Therefore, consider this error as a "false positive" and not a cause for concern unless accompanied by other symptoms of service degradation.

The above is the detailed content of Why Does My Heroku Go WebSocket App Generate False Positive H15 Errors on Connection Close?. For more information, please follow other related articles on the PHP Chinese website!