Polly | NET resilience and transient-fault-handling library | Testing library

I'm having a problem using Polly while trying to accomplish the following:

• Reconnect logic - I tried to create a Polly policy which works when you try to execute StartAsync without Internet connection. However, when it reaches ReceiveLoop, the policy has no longer impact over that method and if our connection stops at that point, it never tries to reconnect back. It simply throws the following exception: Disconnected: The remote party closed the WebSocket connection without completing the close handshake.. Perhaps I should have two policies: one in StartAsync and one in ReceiveLoop, but for some reason it doesn't feel right to me, so that's why I ask the question.

• Timeouts - I want to add timeouts for each ClientWebSocket method call e.g. ConnectAsync, SendAsync, etc. I'm not so familiar with Polly but I believe this policy automatically does that for us. However, I need someone to confirm that. By timeout, I mean similar logic to _webSocket.ConnectAsync(_url, CancellationToken.None).TimeoutAfter(timeoutMilliseconds), TimeoutAfter implementation can be found here. An example how other repos did it can be found here.

Simplified, I want to make this class resilient, which means instead of trying to connect to a dead web socket server for 30 seconds without success, no matter what the reason is, it should fail fast -> retry in 10 seconds -> fail fast -> retry again and so on. This wait and retry logic should be repeated until we call StopAsync or dispose the instance.

You can find the WebSocketDuplexPipe class on GitHub.

I have implemented Polly in it's own "retry" HttpClient DelegateHandler in a dll written to .NET Standard 2.0. I have the Polly v7.2.3 package. My HttpClient is running separate from an HttpClientFactory since only one instance will ever exist during the short lifetime of the dll.

My problem is this: The code executes great when my internet is working. However, when I disconnect my internet it throws a TaskCanceledException on the first retry and does not retry any more. Here are the relevant parts of my code...

inside the ctor of my typed HttpClient:

Although High Sierra is no longer supported by Homebrew, but I need to install llvm@13 formula as a dependency for other formulas. So I tried to install it this way:

I'm inspecting some code that seems to throw

System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host at times.

We use the library Polly for auto retries for HttpClient requests.

• I'm starting to wonder if it has to do with the HttpClient.PostAsync not being awaited below?
• Would that cause any connection exhaustion?

Any guidance would be appreciated.

I have a workflow like this:

• call an API method
  • if any exception is thrown but timeout, the program logs that exception and throws it.
• if timeout is thrown, the program has to call another API method.
  • after calling another API method, if everything goes true, the program returns a result.
  • otherwise the program throws an exception and log it.

both API methods have the same type of result. I want to implement this with polly policies.

This is my sample code:

Currently, Polly Retry policy retires all the failed requests independently. So, if there are 10 requests failing and I have set the retry forever policy then it will send 10 more requests every time a retry happens and the server will never heal.

How to asynchronously pass all failed requests and retry only one request and resume the normal flow if a retry is successful?

I can't (don't want to) use Circuit Breaker because my service is a Background worker service and Circuit Breaker breaks the whole background service logic.

Need to make all the existing repos (around 30+) fault tolerant to deadlock and recover from it with log and wait approach.

Tried with success: I've answered below a custom SqlResiliencyPolicy using Polly after some research and tailored it to the project.

But, what I seek: The present way (PFB answered), demands me to either

1. Wrap all the existing DB calls with await _policy.ExecuteAsync OR
2. Provide custom overloads which accepts IAsyncPolicy param. and later call the intended method. Sort of extension to IDbConnection:

public static Task GetAsync(this IDbConnection connection, object primaryKey, IAsyncPolicy policy) => return await _policy.ExecuteAsync(async () => GetAsync (...));

In both ways, I need to change all my 30+ repos. But, is there a built-in way in dapper/some-other-approaches, where we can

"configure a Policy in startup and auto-magically all DB calls via dapper become resilient (fall backs to their fault tolerant mechanism) Similar to the ways of http clients resilience where policy is added while you register a client"

By this: will've code changes to minimum, need not touch repos but only the startup.

I've a below approach and sort of need an improvement over it.

We started using the Polly library in our legacy WinForms project which still runs on the .NET 4.0 framework (is a requisite).

The problem is that we have to use version 4.3 of the Polly library and it is difficult to find solutions to the problems because all the documentation we find is about more recent versions of the library.

For example we can't pass Context values from retry callback to execute because Context is readonly and we can't pass parameters to execute delegate because it use an Action type.

To all these problems we have find a creative solution but we can't still found a way to stop the execution on certain condition.

In Polly 5, CancellationToken was introduced for this purpose but I guess there were ways to force the retry to stop in previous versions as well.

I've been reading this which seems to have a way of doing what I want.

I've got something similar obviously, but within the PolicyContextExtensions the context.TryGetValue takes PolicyContextItems. This shows as an undefined object for me.

Where does this come from and how is this set?

For reference here is the PolicyContextExtensions class: