Changes using fluent configuration API from Polly. Still to be cleaned up and old Policy code to be removed, etc.
This commit is contained in:
Cesar De la Torre Llorente
parent
18e6dc4afb
commit
dc5de83747
@ -1,5 +1,7 @@
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using Microsoft.Extensions.Logging;
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using Polly;
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using Polly.CircuitBreaker;
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using Polly.Retry;
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using System;
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using System.Net.Http;
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@ -7,8 +9,13 @@ namespace WebMVC.Infrastructure
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{
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public class HttpClientDefaultPolicies
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{
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const int RETRY_COUNT = 6;
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const int EXCEPTIONS_ALLOWED_BEFORE_CIRCUIT_BREAKER = 5;
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//Config for Retries with exponential backoff policy
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const int MAX_RETRIES = 6;
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const int SECONDS_BASE_FOR_EXPONENTIAL_BACKOFF = 2;
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//Config for Circuit Breaker policy
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const int EXCEPTIONS_ALLOWED_BEFORE_CIRCUIT_BREAKES = 5;
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const int DURATION_OF_BREAK_IN_MINUTES = 1;
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private readonly ILogger<HttpClientDefaultPolicies> _logger;
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@ -17,44 +24,51 @@ namespace WebMVC.Infrastructure
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_logger = logger ?? throw new ArgumentNullException(nameof(logger));
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}
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public Policy GetWaitAndRetryPolicy()
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public IAsyncPolicy<HttpResponseMessage> GetWaitAndRetryPolicy()
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{
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return Policy.Handle<HttpRequestException>()
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.WaitAndRetryAsync(
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// number of retries
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RETRY_COUNT,
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// exponential backofff
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retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)),
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// on retry
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(exception, timeSpan, retryCount, context) =>
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{
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var msg = $"Retry {retryCount} implemented with Polly's RetryPolicy " +
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$"of {context.PolicyKey} " +
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$"at {context.OperationKey}, " +
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$"due to: {exception}.";
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_logger.LogWarning(msg);
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_logger.LogDebug(msg);
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});
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RetryPolicy retryPolicy =
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Policy.Handle<HttpRequestException>()
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.WaitAndRetryAsync(
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// Maximum number of retries
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MAX_RETRIES,
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// exponential backofff (2sg, 4sg, 8sg, 16sg, 32sg. etc.)
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retryAttempt => TimeSpan.FromSeconds(Math.Pow(SECONDS_BASE_FOR_EXPONENTIAL_BACKOFF, retryAttempt)),
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// on retry
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(exception, timeSpan, retryCount, context) =>
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{
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var msg = $"Retry {retryCount} implemented with Polly's RetryPolicy " +
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$"of {context.PolicyKey} " +
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$"at {context.OperationKey}, " +
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$"due to: {exception}.";
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_logger.LogWarning(msg);
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_logger.LogDebug(msg);
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});
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return retryPolicy.AsAsyncPolicy<HttpResponseMessage>();
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}
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public Policy GetCircuitBreakerPolicy()
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public IAsyncPolicy<HttpResponseMessage> GetCircuitBreakerPolicy()
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{
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return Policy.Handle<HttpRequestException>()
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.CircuitBreakerAsync(
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// number of exceptions before breaking circuit
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EXCEPTIONS_ALLOWED_BEFORE_CIRCUIT_BREAKER,
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// time circuit opened before retry
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TimeSpan.FromMinutes(1),
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(exception, duration) =>
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{
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// on circuit opened
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_logger.LogTrace("Circuit breaker opened");
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},
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() =>
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{
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// on circuit closed
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_logger.LogTrace("Circuit breaker reset");
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});
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CircuitBreakerPolicy circuitBreakerPolicy =
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Policy.Handle<HttpRequestException>()
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.CircuitBreakerAsync(
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// Number of exceptions before breaking the circuit
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EXCEPTIONS_ALLOWED_BEFORE_CIRCUIT_BREAKES,
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// Duration of break
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TimeSpan.FromMinutes(DURATION_OF_BREAK_IN_MINUTES),
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(exception, duration) =>
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{
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// On circuit opened (Circuit is broken)
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_logger.LogTrace("Circuit has been broken");
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},
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() =>
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{
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// on circuit closed
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_logger.LogTrace("Circuit has been reset");
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});
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return circuitBreakerPolicy.AsAsyncPolicy<HttpResponseMessage>();
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}
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}
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}
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@ -15,7 +15,11 @@ using Microsoft.Extensions.DependencyInjection;
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using Microsoft.Extensions.HealthChecks;
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using Microsoft.Extensions.Logging;
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using Polly;
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using Polly.CircuitBreaker;
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using Polly.Extensions.Http;
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using Polly.Registry;
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using Polly.Retry;
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using Polly.Timeout;
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using StackExchange.Redis;
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using System;
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using System.IdentityModel.Tokens.Jwt;
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@ -35,13 +39,13 @@ namespace Microsoft.eShopOnContainers.WebMVC
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public IConfiguration Configuration { get; }
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// This method gets called by the runtime. Use this method to add services to the container.
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// This method gets called by the runtime. Use this method to add services to the IoC container.
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public void ConfigureServices(IServiceCollection services)
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{
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services.AddAppInsight(Configuration)
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.AddHealthChecks(Configuration)
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.AddCustomMvc(Configuration)
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.AddCustomApplicationServices(Configuration)
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.AddHttpClientServices(Configuration)
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.AddCustomAuthentication(Configuration);
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}
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@ -165,28 +169,89 @@ namespace Microsoft.eShopOnContainers.WebMVC
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return services;
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}
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public static IServiceCollection AddCustomApplicationServices(this IServiceCollection services, IConfiguration configuration)
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// Adds all Http client services (like Service-Agents) using resilient Http requests based on HttpClient factory and Polly's policies
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public static IServiceCollection AddHttpClientServices(this IServiceCollection services, IConfiguration configuration)
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{
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// (CDLTLL) TEMPORAL COMMENT: Do we need this line of code if using HttpClient factory?
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services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
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// (CDLTLL) I don't think we need this HttpClientDefaultPolicies if using fluent configuration ,as below...
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// Create a singleton object with the by default policies
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services.AddSingleton<HttpClientDefaultPolicies>();
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var defaultPolicies = services.BuildServiceProvider().GetService<HttpClientDefaultPolicies>();
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var registry = services.AddPolicyRegistry();
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registry.Add("WaitAndRetry", defaultPolicies.GetWaitAndRetryPolicy());
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registry.Add("CircuitBreaker", defaultPolicies.GetCircuitBreakerPolicy());
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// Create a Polly-Policy-Registry with the by default policies for resilient Http requests
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var pollyPolicyRegistry = services.AddPolicyRegistry();
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//Using fluent client configuration of Polly policies
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var retriesWithExponentialBackoff = HttpPolicyExtensions
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.HandleTransientHttpError()
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.WaitAndRetryAsync(7,
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retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
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);
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//(CDLTLL) Instead of hardcoded values, use: configuration["HttpClientMaxNumberRetries"], configuration["SecondsBaseForExponentialBackoff"]
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var circuitBreaker = HttpPolicyExtensions
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.HandleTransientHttpError()
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.CircuitBreakerAsync(6,
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TimeSpan.FromSeconds(30)
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);
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//(CDLTLL) Instead of hardcoded values, use: configuration["HttpClientExceptionsAllowedBeforeBreaking"], configuration["DurationOfBreakInMinutes"]
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pollyPolicyRegistry.Add("DefaultRetriesWithExponentialBackoff", retriesWithExponentialBackoff);
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pollyPolicyRegistry.Add("DefaultCircuitBreaker", circuitBreaker);
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// (CDLTLL) Using "OLD" policies. I don't like it much...
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//pollyPolicyRegistry.Add("DefaultRetriesWithExponentialBackoff", defaultPolicies.GetWaitAndRetryPolicy()); // (CDLTLL) TEMPORAL COMMENT: Arguments here would be a good place to propagate the configuration values --> GetWaitAndRetryPolicy(configuration["HttpClientMaxNumberRetries"], configuration["SecondsBaseForExponentialBackoff"])
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//pollyPolicyRegistry.Add("DefaultCircuitBreaker", defaultPolicies.GetCircuitBreakerPolicy()); // (CDLTLL) TEMPORAL COMMENT: Arguments here would be a good place to propagate the configuration values --> GetCircuitBreakerPolicy(configuration["HttpClientExceptionsAllowedBeforeBreaking"], configuration["DurationOfBreakInMinutes"])
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// (CDLTLL) Handlers need to be transient. //(CDLTLL) TEMPORAL COMMENT: This registration was missing, hence the error "InvalidOperationException: No service for type 'WebMVC.Infrastructure.HttpClientAuthorizationDelegatingHandler' has been registered"
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services.AddTransient<HttpClientAuthorizationDelegatingHandler>();
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//Add all Typed-Clients (Service-Agents) through the HttpClient factory to implement Resilient Http requests
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//
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//Add BasketService typed client (Service Agent)
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services.AddHttpClient<IBasketService, BasketService>()
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.AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>()
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.AddPolicyHandlerFromRegistry("WaitAndRetry")
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.AddPolicyHandlerFromRegistry("CircuitBreaker");
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.AddHttpMessageHandler<HttpClientAuthorizationDelegatingHandler>() //Additional Authentication-Delegating-Handler to add the OAuth-Bearer-token to the Http headers
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.AddPolicyHandlerFromRegistry("DefaultRetriesWithExponentialBackoff")
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.AddPolicyHandlerFromRegistry("DefaultCircuitBreaker");
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//Add CatalogService typed client (Service Agent)
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//services.AddHttpClient<ICatalogService, CatalogService>() ...
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//Add OrderingService typed client (Service Agent)
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//services.AddHttpClient<IOrderingService, OrderingService>() ...
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//Add CampaignService typed client (Service Agent)
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//services.AddHttpClient<ICampaignService, CampaignService>() ...
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//Add LocationService typed client (Service Agent)
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//services.AddHttpClient<ILocationService, LocationService>() ...
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//Add IdentityParser typed client (Service Agent)
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//services.AddHttpClient<IIdentityParser, IdentityParser>() ...
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// (CDLTLL) TEMPORAL COMMENT: The following Typed-Clients (Service-Agents) have to be coded as BasketService by using AddHttpClient<>(), right?
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// This code will be deleted
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services.AddTransient<ICatalogService, CatalogService>();
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services.AddTransient<IOrderingService, OrderingService>();
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services.AddTransient<ICampaignService, CampaignService>();
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services.AddTransient<ILocationService, LocationService>();
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services.AddTransient<IIdentityParser<ApplicationUser>, IdentityParser>();
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// TEMPORAL COMMENT: This code will be deleted when using HttpClientFactory, right?
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if (configuration.GetValue<string>("UseResilientHttp") == bool.TrueString)
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{
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services.AddSingleton<IResilientHttpClientFactory, ResilientHttpClientFactory>(sp =>
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@ -214,6 +279,7 @@ namespace Microsoft.eShopOnContainers.WebMVC
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{
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services.AddSingleton<IHttpClient, StandardHttpClient>();
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}
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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return services;
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}
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