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Add example for chaos engineering #1956

Merged
merged 3 commits into from
Feb 5, 2024
Merged

Add example for chaos engineering #1956

merged 3 commits into from
Feb 5, 2024

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martintmk
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@martintmk martintmk commented Feb 5, 2024

Pull Request

The issue or feature being addressed

Contributes to #1954

Details on the issue fix or feature implementation

An example of how to use chaos strategies alongside the resilience. This sample will be referenced in the upcoming blog post about chaos engineering with Polly.

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  • I started this PR by branching from the head of the default branch
  • I have targeted the PR to merge into the default branch
  • I have included unit tests for the issue/feature
  • I have successfully run a local build

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All modified and coverable lines are covered by tests ✅

Comparison is base (f3e78ee) 85.91% compared to head (29f1157) 85.91%.

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var builder = WebApplication.CreateBuilder(args);
var services = builder.Services;
services.TryAddSingleton<IChaosManager, ChaosManager>();
services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
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Could just use the AddHttpContextAccessor() method?

# Chaos Example

This example demonstrates how to use new [chaos engineering](https://www.pollydocs.org/chaos) tools in Polly to inject chaos into HTTP client communication.
The HTTP client communicates with `https://jsonplaceholder.typicode.com/todos` endpoint.
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Suggested change
The HTTP client communicates with `https://jsonplaceholder.typicode.com/todos` endpoint.
The HTTP client communicates with the `https://jsonplaceholder.typicode.com/todos` endpoint.


To test the application:

- Run the app using `dotnet run` command.
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Suggested change
- Run the app using `dotnet run` command.
- Run the app using the `dotnet run` command.

public async Task<IEnumerable<TodoModel>?> GetTodosAsync(CancellationToken cancellationToken)
{
using var request = new HttpRequestMessage(HttpMethod.Get, "/todos");
using var response = await client.SendAsync(request, cancellationToken);
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@martincostello martincostello Feb 5, 2024

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Could simplify this down to just use GetFromJsonAsync<T>()?

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I wanted to include handling of invalid status codes which is not possible with that method.

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I thought that method implicitly called EnsureStatusCode() for you, so it's basically the same? I meant the one that's an overload of HttpClient.

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Based on my understanding it does not do status code checking. (it would prevent deserializing error bodies for example).

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Oh, if that's the case I've been using it wrong a lot then. I assumed it checked the status code, as otherwise you'd get a weird result if you tried to deserialise the response as a model for an OK and instead the body was an ErrorDetails or an HTML error page or something.

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Also it would be weird to do a get knowing in advance you were just going to get an error details because it would fail. Not checking the status would make more sense if it was a discriminated union.

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You are right, it checks the status code as well. Simplified.

@martintmk martintmk enabled auto-merge (squash) February 5, 2024 20:57
@martintmk martintmk enabled auto-merge (squash) February 5, 2024 21:27
@martintmk martintmk merged commit de6d4b3 into main Feb 5, 2024
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@martintmk martintmk deleted the mtomka/chaos-sample branch February 5, 2024 22:01
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2 participants