#2080 Add new FailureRatio and SamplingDuration V8 parameters to fine-tune Polly's circuit-breaker strategy via route-level and global QoS options

[RaynaldM]

Closes #2080

• FailureRatio and SamplingDuration parameters of Polly V8 circuit-breaker #2080

This PR adds 2 new parameters in QoSOptions to fine-tune circuit-breaker behavior 👉

• FailureRatio: The failure-success ratio that will cause the circuit to break/open.
• SamplingDuration: The time period over which the failure-success ratio is calculated (in seconds).

Predecessor

• #1314 #1869 #2072 Default timeout for all levels, including route, global, and QoS #2073

[raman-m]

Great! Which version are you planning to release it in?

Please note that the PR depends on #2073, which needs to be merged before this PR. Therefore, this feature branch should be rebased after the merging of #2073, and ideally, after #2079 is merged as well.

It appears that it won't be included in version 23.3, but rather in version 24.0, which is the next release following v23.3.
Is this delivery acceptable to you?

[RaynaldM]

Great! Which version are you planning to release it in?

Please note that the PR depends on #2073, which needs to be merged before this PR. Therefore, this feature branch should be rebased after the merging of #2073, and ideally, after #2079 is merged as well.

It appears that it won't be included in version 23.3, but rather in version 24.0, which is the next release following v23.3. Is this delivery acceptable to you?

Yes, @raman-m, you can add this when you want

[raman-m]

@RaynaldM
Please resolve conflicts!
PR has been added to v24.0 milestone, current release

[raman-m]

@RaynaldM Conflicts!

[raman-m]

Let's assign this to the Sep'24 milestone since the Annual 2023 milestone is already quite overloaded, and we need to reduce the scope of work for 2023.

[raman-m]

Tasks

• Create acceptance tests to ensure global QoS configuration is accessible in the PollyQoSResiliencePipelineProvider class → Done in commit 51be1a3 ✔️
• Refactor the provider class and clean up all code related to global QoS injection → Done in commit 3c386c1 ✔️
• Verify unit test coverage thoroughly → Done in commits 5b92dce and 0c29c00 ✔️
• Update documentation → Done in commit dfe4ba6 ✔️

[raman-m]

@ggnaegi
Gui, this commit 7d73299 was specially made for you. Here is my explanation to you...

TODO Override the Equals method of the DownstreamRoute class

The image above illustrates runtime debugging of the comparer being used to compare two DownstreamRoute class instances, which are reference types. In the test from the commit, I demonstrated that the standard object.Equals(object) method is called for comparison. However, this default implementation relies on comparing memory references. Therefore, we need to implement the entire stack as per .NET documentation to properly compare DownstreamRoute class instances. Unfortunately, the DownstreamRoute class currently lacks such logic.
The ultimate goal is to eliminate the MessageInvokerCacheKey structure since the DownstreamRoute class should have its own overridden version of the Equals method. Once DownstreamRoute includes all overridden versions for Equals, GetHashCode, and (in)equality operators, we can replace the MessageInvokerCacheKey class with DownstreamRoute as the key type for the relevant concurrent dictionary.
We need to run tests to ensure that the caching in the pool is functional and uses minimal RAM, allowing it to be effectively reused.
This task is not straightforward and might require significant effort due to potential cascading changes. However, we could avoid these issues by adding a simple route ID or number property as an integer, which is the most efficient type for hashing and caching. To my knowledge, the well-known Bla-bla gateway already implements an ID property for route objects. This should be considered for future development.

[raman-m]

Ready for delivery ✅

• Code review ✔️
• Unit testing ✔️✔️
• Acceptance testing ✔️
• Updated docs ✔️

[raman-m]

@RaynaldM Hi Ray!
Thanks for your contribution!
There are more resilience strategies waiting for you to add to Ocelot's Polly provider. 😉