Correctly use HttpClient instances across the entire framework

[guilhermeluizsp]

HttpClient is intended to be reused as much as possible throughout the entire application.
Internally, it uses an object of type HttpClientHandler, which actually makes the HTTP requests. By default, even when disposed, the underlying socket will not be immediately released, keeping them with the TIME_WAIT state. When in TIME_WAIT, the socket cannot be reused, and under heavy loading it can cause a socket exhaustion, preventing the system from making more requests (for a limited amount of time).

LightAPI uses an instance of HttpClient under the hood, obviously using one instance for each LightAPI instance.
As it doesn't change the default implementation of HttpClientHandler, we will inevitably face the problem above.

To fix this problem, Microsoft created a library called HttpClientFactory, which managed the creation of HttpClient instances and their HttpClientHandler's.

The Liquid Framework should use this library by default when dealing with HttpClient-based requests.

HttpClientFactory can also be extended. By default, it has options for setting up resilient requests for every HttpClient created (the same thing as LightAPI does, and it also uses Polly)

[bruno-brant]

Completely agree. Do you belive this to be priority? Are we seeing errors related to socket pool exhaustion?

[guilhermeluizsp]

As I have not used Liquid in a production environment scenario, I have not seen it yet, but setting up manual stress testing (using real life numbers, not absurd values), I was able to face port exhaustion occasionally.

At the same time I think it's an important issue, we still have other crucial problems to solve (such as stopping calling asynchronous methods synchronously).

I would like to reiterate that I still haven't used Liquid in production yet and an exhaustion (in heavy loading) is a strong possibility to happen.

So I'd consider this not to be a priority at the moment.

[bruno-brant]

I'll mark it as a bug, but we will treat it as low priority.