Restructure solution layout by module

src/Authority/StellaOps.Authority/StellaOps.Auth.Client/ServiceCollectionExtensions.cs

@@ -0,0 +1,115 @@
+using System;
+using System.Net;
+using System.Net.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Polly;
+using Polly.Extensions.Http;
+
+namespace StellaOps.Auth.Client;
+
+/// <summary>
+/// DI helpers for the StellaOps auth client.
+/// </summary>
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Registers the StellaOps auth client with the provided configuration.
+    /// </summary>
+    public static IServiceCollection AddStellaOpsAuthClient(this IServiceCollection services, Action<StellaOpsAuthClientOptions> configure)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+        ArgumentNullException.ThrowIfNull(configure);
+
+        services.AddOptions<StellaOpsAuthClientOptions>()
+            .Configure(configure)
+            .PostConfigure(static options => options.Validate());
+
+        services.TryAddSingleton<IStellaOpsTokenCache, InMemoryTokenCache>();
+
+        services.AddHttpClient<StellaOpsDiscoveryCache>((provider, client) =>
+        {
+            var options = provider.GetRequiredService<IOptionsMonitor<StellaOpsAuthClientOptions>>().CurrentValue;
+            client.Timeout = options.HttpTimeout;
+        }).AddPolicyHandler(static (provider, _) => CreateRetryPolicy(provider));
+
+        services.AddHttpClient<StellaOpsJwksCache>((provider, client) =>
+        {
+            var options = provider.GetRequiredService<IOptionsMonitor<StellaOpsAuthClientOptions>>().CurrentValue;
+            client.Timeout = options.HttpTimeout;
+        }).AddPolicyHandler(static (provider, _) => CreateRetryPolicy(provider));
+
+        services.AddHttpClient<IStellaOpsTokenClient, StellaOpsTokenClient>((provider, client) =>
+        {
+            var options = provider.GetRequiredService<IOptionsMonitor<StellaOpsAuthClientOptions>>().CurrentValue;
+            client.Timeout = options.HttpTimeout;
+        }).AddPolicyHandler(static (provider, _) => CreateRetryPolicy(provider));
+
+        return services;
+    }
+
+    /// <summary>
+    /// Registers a file-backed token cache implementation.
+    /// </summary>
+    public static IServiceCollection AddStellaOpsFileTokenCache(this IServiceCollection services, string cacheDirectory)
+    {
+        ArgumentNullException.ThrowIfNull(services);
+        ArgumentException.ThrowIfNullOrWhiteSpace(cacheDirectory);
+
+        services.Replace(ServiceDescriptor.Singleton<IStellaOpsTokenCache>(provider =>
+        {
+            var logger = provider.GetService<Microsoft.Extensions.Logging.ILogger<FileTokenCache>>();
+            var options = provider.GetRequiredService<IOptionsMonitor<StellaOpsAuthClientOptions>>().CurrentValue;
+            return new FileTokenCache(cacheDirectory, TimeProvider.System, options.ExpirationSkew, logger);
+        }));
+
+        return services;
+    }
+
+    private static IAsyncPolicy<HttpResponseMessage> CreateRetryPolicy(IServiceProvider provider)
+    {
+        var options = provider.GetRequiredService<IOptionsMonitor<StellaOpsAuthClientOptions>>().CurrentValue;
+        var delays = options.NormalizedRetryDelays;
+        if (delays.Count == 0)
+        {
+            return Policy.NoOpAsync<HttpResponseMessage>();
+        }
+
+        var logger = provider.GetService<ILoggerFactory>()?.CreateLogger("StellaOps.Auth.Client.HttpRetry");
+
+        return HttpPolicyExtensions
+            .HandleTransientHttpError()
+            .OrResult(static response => response.StatusCode == HttpStatusCode.TooManyRequests)
+            .WaitAndRetryAsync(
+                delays.Count,
+                attempt => delays[attempt - 1],
+                (outcome, delay, attempt, _) =>
+                {
+                    if (logger is null)
+                    {
+                        return;
+                    }
+
+                    if (outcome.Exception is not null)
+                    {
+                        logger.LogWarning(
+                            outcome.Exception,
+                            "Retrying Authority HTTP call ({Attempt}/{TotalAttempts}) after exception; waiting {Delay}.",
+                            attempt,
+                            delays.Count,
+                            delay);
+                    }
+                    else
+                    {
+                        logger.LogWarning(
+                            "Retrying Authority HTTP call ({Attempt}/{TotalAttempts}) due to status {StatusCode}; waiting {Delay}.",
+                            attempt,
+                            delays.Count,
+                            outcome.Result!.StatusCode,
+                            delay);
+                    }
+                });
+    }
+}