public async Task HttpClientFactory_ApplyMultiplePolicies()
{
IServiceCollection services = new ServiceCollection();
///// ADD HTTP CLIENT VIA HTTPCLIENTFACTORY AND POLICIES
// this would typically happen in Startup.ConfigureServices
// using a named client, can specify a <TClient> to inject it into a specific class
// setup circuit breaker seperately so you can maintain a pointer to it for testing (validate state, reset, etc)
var circuitBreakerPolicy = DemoPolicyFactory.GetHttpCircuitBreakerPolicy();
ICircuitBreakerPolicy <HttpResponseMessage> circuitBreakerPointer = (ICircuitBreakerPolicy <HttpResponseMessage>)circuitBreakerPolicy;
services.AddHttpClient("CustomerService",
client =>
{
client.BaseAddress = new Uri(DemoHelper.DemoBaseUrl);
client.Timeout =
TimeSpan.FromSeconds(
3); // this will apply as an outer timeout to the entire request flow, including waits, retries,etc
})
// add policies from outer (1st executed) to inner (closest to dependency call)
// all policies must implement IASyncPolicy
.AddPolicyHandler(DemoPolicyFactory.GetHttpFallbackPolicy("Default!"))
.AddPolicyHandler(DemoPolicyFactory.GetHttpRetryPolicy())
.AddPolicyHandler(circuitBreakerPolicy)
.AddPolicyHandler(DemoPolicyFactory.GetHttpInnerTimeoutPolicy());
///// TEST POLICIES /////
await VerifyResiliencyPolicies(services, circuitBreakerPointer);
}
public async Task HttpClientFactory_OnlyApplyPolicyToGetRequests()
{
IServiceCollection services = new ServiceCollection();
services.AddHttpClient("CustomerService",
client =>
{
client.BaseAddress = new Uri(DemoHelper.DemoBaseUrl);
client.Timeout =
TimeSpan.FromSeconds(3);
})
.AddPolicyHandler(request =>
request.Method == HttpMethod.Get
? DemoPolicyFactory.GetHttpRetryPolicy()
: Policy.NoOpAsync <HttpResponseMessage>());
var serviceProvider = services.BuildServiceProvider();
var clientFactory = serviceProvider.GetService <IHttpClientFactory>();
var httpClient = clientFactory.CreateClient("CustomerService");
var responseMessage = await httpClient.GetAsync("api/demo/error?failures=1");
Assert.IsTrue(responseMessage.IsSuccessStatusCode);
}