feat: add endpoint benchmarking on startup

- New EndpointBenchmarkService pings all endpoints on startup
- Measures average response time and success rate
- Reorders endpoints by performance (fastest first)
- RoundRobinFallbackHelper now uses benchmarked order
- Racing still happens, but starts with fastest endpoints
- Reduces latency by prioritizing known-fast servers
- Logs benchmark results for visibility

allstarr/Program.cs

@@ -477,6 +477,9 @@ else
     builder.Services.AddSingleton<IStartupValidator, SubsonicStartupValidator>();
 }
 
+// Register endpoint benchmark service
+builder.Services.AddSingleton<EndpointBenchmarkService>();
+
 builder.Services.AddSingleton<IStartupValidator, DeezerStartupValidator>();
 builder.Services.AddSingleton<IStartupValidator, QobuzStartupValidator>();
 builder.Services.AddSingleton<IStartupValidator>(sp =>
@@ -484,6 +487,7 @@ builder.Services.AddSingleton<IStartupValidator>(sp =>
         sp.GetRequiredService<Microsoft.Extensions.Options.IOptions<SquidWTFSettings>>(),
         sp.GetRequiredService<IHttpClientFactory>().CreateClient(),
         squidWtfApiUrls,
+        sp.GetRequiredService<EndpointBenchmarkService>(),
         sp.GetRequiredService<ILogger<SquidWTFStartupValidator>>()));
 builder.Services.AddSingleton<IStartupValidator, LyricsStartupValidator>();
 

allstarr/Services/Common/EndpointBenchmarkService.cs

@@ -0,0 +1,135 @@
+using System.Diagnostics;
+
+namespace allstarr.Services.Common;
+
+/// <summary>
+/// Benchmarks API endpoints on startup and maintains performance metrics.
+/// Used to prioritize faster endpoints in racing scenarios.
+/// </summary>
+public class EndpointBenchmarkService
+{
+    private readonly ILogger<EndpointBenchmarkService> _logger;
+    private readonly Dictionary<string, EndpointMetrics> _metrics = new();
+    private readonly SemaphoreSlim _lock = new(1, 1);
+
+    public EndpointBenchmarkService(ILogger<EndpointBenchmarkService> logger)
+    {
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Benchmarks a list of endpoints by making test requests.
+    /// Returns endpoints sorted by average response time (fastest first).
+    /// </summary>
+    public async Task<List<string>> BenchmarkEndpointsAsync(
+        List<string> endpoints, 
+        Func<string, CancellationToken, Task<bool>> testFunc,
+        int pingCount = 3,
+        CancellationToken cancellationToken = default)
+    {
+        _logger.LogInformation("🏁 Benchmarking {Count} endpoints with {Pings} pings each...", endpoints.Count, pingCount);
+
+        var tasks = endpoints.Select(async endpoint =>
+        {
+            var sw = Stopwatch.StartNew();
+            var successCount = 0;
+            var totalMs = 0L;
+
+            for (int i = 0; i < pingCount; i++)
+            {
+                try
+                {
+                    var pingStart = Stopwatch.GetTimestamp();
+                    var success = await testFunc(endpoint, cancellationToken);
+                    var pingMs = Stopwatch.GetElapsedTime(pingStart).TotalMilliseconds;
+
+                    if (success)
+                    {
+                        successCount++;
+                        totalMs += (long)pingMs;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogDebug(ex, "Benchmark ping failed for {Endpoint}", endpoint);
+                }
+
+                // Small delay between pings
+                if (i < pingCount - 1)
+                {
+                    await Task.Delay(100, cancellationToken);
+                }
+            }
+
+            sw.Stop();
+
+            var avgMs = successCount > 0 ? totalMs / successCount : long.MaxValue;
+            var metrics = new EndpointMetrics
+            {
+                Endpoint = endpoint,
+                AverageResponseMs = avgMs,
+                SuccessRate = (double)successCount / pingCount,
+                LastBenchmark = DateTime.UtcNow
+            };
+
+            await _lock.WaitAsync(cancellationToken);
+            try
+            {
+                _metrics[endpoint] = metrics;
+            }
+            finally
+            {
+                _lock.Release();
+            }
+
+            _logger.LogInformation("  {Endpoint}: {AvgMs}ms avg, {SuccessRate:P0} success rate", 
+                endpoint, avgMs, metrics.SuccessRate);
+
+            return metrics;
+        }).ToList();
+
+        var results = await Task.WhenAll(tasks);
+
+        // Sort by: success rate first (must be > 0), then by average response time
+        var sorted = results
+            .Where(m => m.SuccessRate > 0)
+            .OrderByDescending(m => m.SuccessRate)
+            .ThenBy(m => m.AverageResponseMs)
+            .Select(m => m.Endpoint)
+            .ToList();
+
+        _logger.LogInformation("✅ Benchmark complete. Fastest: {Fastest} ({Ms}ms)", 
+            sorted.FirstOrDefault() ?? "none", 
+            results.Where(m => m.SuccessRate > 0).MinBy(m => m.AverageResponseMs)?.AverageResponseMs ?? 0);
+
+        return sorted;
+    }
+
+    /// <summary>
+    /// Gets the metrics for a specific endpoint.
+    /// </summary>
+    public EndpointMetrics? GetMetrics(string endpoint)
+    {
+        _metrics.TryGetValue(endpoint, out var metrics);
+        return metrics;
+    }
+
+    /// <summary>
+    /// Gets all endpoint metrics sorted by performance.
+    /// </summary>
+    public List<EndpointMetrics> GetAllMetrics()
+    {
+        return _metrics.Values
+            .OrderByDescending(m => m.SuccessRate)
+            .ThenBy(m => m.AverageResponseMs)
+            .ToList();
+    }
+}
+
+public class EndpointMetrics
+{
+    public string Endpoint { get; set; } = string.Empty;
+    public long AverageResponseMs { get; set; }
+    public double SuccessRate { get; set; }
+    public DateTime LastBenchmark { get; set; }
+}

allstarr/Services/Common/RoundRobinFallbackHelper.cs

@@ -26,6 +26,31 @@ public class RoundRobinFallbackHelper
         }
     }
 
+    /// <summary>
+    /// Updates the endpoint order based on benchmark results (fastest first).
+    /// </summary>
+    public void SetEndpointOrder(List<string> orderedEndpoints)
+    {
+        lock (_urlIndexLock)
+        {
+            // Reorder _apiUrls to match the benchmarked order
+            var reordered = orderedEndpoints.Where(e => _apiUrls.Contains(e)).ToList();
+            
+            // Add any endpoints that weren't benchmarked (shouldn't happen, but be safe)
+            foreach (var url in _apiUrls.Where(u => !reordered.Contains(u)))
+            {
+                reordered.Add(url);
+            }
+
+            _apiUrls.Clear();
+            _apiUrls.AddRange(reordered);
+            _currentUrlIndex = 0;
+
+            _logger.LogInformation("📊 {Service} endpoints reordered by benchmark: {Endpoints}", 
+                _serviceName, string.Join(", ", _apiUrls.Take(3)));
+        }
+    }
+
     /// <summary>
     /// Tries the request with the next provider in round-robin, then falls back to others on failure.
     /// This distributes load evenly across all providers while maintaining reliability.

allstarr/Services/SquidWTF/SquidWTFStartupValidator.cs

@@ -14,14 +14,23 @@ public class SquidWTFStartupValidator : BaseStartupValidator
 {
     private readonly SquidWTFSettings _settings;
     private readonly RoundRobinFallbackHelper _fallbackHelper;
+    private readonly EndpointBenchmarkService _benchmarkService;
+    private readonly ILogger<SquidWTFStartupValidator> _logger;
 
     public override string ServiceName => "SquidWTF";
 
-    public SquidWTFStartupValidator(IOptions<SquidWTFSettings> settings, HttpClient httpClient, List<string> apiUrls, ILogger<SquidWTFStartupValidator> logger)
+    public SquidWTFStartupValidator(
+        IOptions<SquidWTFSettings> settings, 
+        HttpClient httpClient, 
+        List<string> apiUrls, 
+        EndpointBenchmarkService benchmarkService,
+        ILogger<SquidWTFStartupValidator> logger)
         : base(httpClient)
     {
         _settings = settings.Value;
         _fallbackHelper = new RoundRobinFallbackHelper(apiUrls, logger, "SquidWTF");
+        _benchmarkService = benchmarkService;
+        _logger = logger;
     }
     
 	
@@ -41,6 +50,47 @@ public class SquidWTFStartupValidator : BaseStartupValidator
 
         WriteStatus("SquidWTF Quality", quality, ConsoleColor.Cyan);
 
+        // Benchmark all endpoints to determine fastest
+        var apiUrls = _fallbackHelper.EndpointCount > 0 
+            ? Enumerable.Range(0, _fallbackHelper.EndpointCount).Select(_ => "").ToList() // Placeholder, we'll get actual URLs from fallback helper
+            : new List<string>();
+
+        // Get the actual API URLs by reflection (not ideal, but works for now)
+        var fallbackHelperType = _fallbackHelper.GetType();
+        var apiUrlsField = fallbackHelperType.GetField("_apiUrls", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
+        if (apiUrlsField != null)
+        {
+            apiUrls = (List<string>)apiUrlsField.GetValue(_fallbackHelper)!;
+        }
+
+        if (apiUrls.Count > 1)
+        {
+            WriteStatus("Benchmarking Endpoints", $"{apiUrls.Count} endpoints", ConsoleColor.Cyan);
+            
+            var orderedEndpoints = await _benchmarkService.BenchmarkEndpointsAsync(
+                apiUrls,
+                async (endpoint, ct) =>
+                {
+                    try
+                    {
+                        var response = await _httpClient.GetAsync(endpoint, ct);
+                        return response.IsSuccessStatusCode;
+                    }
+                    catch
+                    {
+                        return false;
+                    }
+                },
+                pingCount: 2,
+                cancellationToken);
+
+            if (orderedEndpoints.Count > 0)
+            {
+                _fallbackHelper.SetEndpointOrder(orderedEndpoints);
+                WriteDetail($"Fastest endpoint: {orderedEndpoints.First()}");
+            }
+        }
+
         // Test connectivity with fallback
         var result = await _fallbackHelper.TryWithFallbackAsync(async (baseUrl) =>
         {