Ocelot: UnableToCompleteRequestError

[clintcarter1999]

I added logging to the API Gateway which uses Ocelot. This .Net Core 2.2 API is running on a linux server.
I added middleware to log the request IP address.

It appears to route requests just fine.

However, it never hits my middleware and instead is logging this exception from Ocelot.

[2022-09-15 17:02:50.5415][vmc-mercub][Warn] requestId: 0HMKNC1L9QQOG:00000001, previousRequestId: no previous request id, message: 
Error Code: **UnableToCompleteRequestError** 
Message: Error making http request, 
exception: System.Threading.Tasks.TaskCanceledException: The operation was canceled. ---> 
System.IO.IOException: Unable to read data from the transport connection: 
Operation canceled. ---> System.Net.Sockets.SocketException: Operation canceled
   --- End of inner exception stack trace ---
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error)
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.GetResult(Int16 token)
   at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
   at Ocelot.Requester.HttpClientHttpRequester.GetResponse(DownstreamContext context) errors found in ResponderMiddleware. Setting error response for request path:/api/v1.0/Parts/Inventory, request method: POST 

Thoughts? Ideas? on what could be causing this?

[ks1990cn]

Can you share code hints of what and where you have put middleware?

Also Oclelot, looks like something wrong with socket

[raman-m]

Hi Clint !
Welcome to Ocelot world!

Please attach more details: configuration JSON, and C# code of your module, startup config also.

System.Net.Sockets.SocketException: Operation canceled
Seems your connection was aborted, canceled or closed by Websocket peer.

---

his .Net Core 2.2 API is running on a linux server.

Oh, this is quite old and legacy .NET framework!
You have to update your downstream service running .NET Core 2.2.
Pay attention that Ocelot and downstream service can have different .NET versions which lead to malfunctioning of WebSocket and even HttpClient!
So, I would say this error could be .NET version (System.Net clients) incompatibility problem.
So, Ocelot or downstream service Websocket app as a WebSocket peer can close the connection if protocol versions differ.

Finally, please upgrade your downstream .NET app from 2.2 to 6+ version. .NET 8 ideally.