Refactor ConfigValidator (#2293)

src/ReverseProxy/Configuration/ClusterValidators/DestinationValidator.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class DestinationValidator : IClusterValidator
+{
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (cluster.Destinations is null)
+        {
+            return ValueTask.CompletedTask;
+        }
+
+        foreach (var (name, destination) in cluster.Destinations)
+        {
+            if (string.IsNullOrEmpty(destination.Address))
+            {
+                errors.Add(new ArgumentException($"No address found for destination '{name}' on cluster '{cluster.ClusterId}'."));
+            }
+        }
+
+        return ValueTask.CompletedTask;
+    }
+}

src/ReverseProxy/Configuration/ClusterValidators/HealthCheckValidator.cs

@@ -0,0 +1,101 @@
+using System;
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Yarp.ReverseProxy.Health;
+using Yarp.ReverseProxy.Utilities;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class HealthCheckValidator : IClusterValidator
+{
+    private readonly FrozenDictionary<string, IAvailableDestinationsPolicy> _availableDestinationsPolicies;
+    private readonly FrozenDictionary<string, IActiveHealthCheckPolicy> _activeHealthCheckPolicies;
+    private readonly FrozenDictionary<string, IPassiveHealthCheckPolicy> _passiveHealthCheckPolicies;
+
+    public HealthCheckValidator(IEnumerable<IAvailableDestinationsPolicy> availableDestinationsPolicies,
+        IEnumerable<IActiveHealthCheckPolicy> activeHealthCheckPolicies,
+        IEnumerable<IPassiveHealthCheckPolicy> passiveHealthCheckPolicies)
+    {
+        _availableDestinationsPolicies = availableDestinationsPolicies?.ToDictionaryByUniqueId(p => p.Name) ?? throw new ArgumentNullException(nameof(availableDestinationsPolicies));
+        _activeHealthCheckPolicies = activeHealthCheckPolicies?.ToDictionaryByUniqueId(p => p.Name) ?? throw new ArgumentNullException(nameof(availableDestinationsPolicies));
+        _passiveHealthCheckPolicies = passiveHealthCheckPolicies?.ToDictionaryByUniqueId(p => p.Name) ?? throw new ArgumentNullException(nameof(availableDestinationsPolicies));
+    }
+
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        var availableDestinationsPolicy = cluster.HealthCheck?.AvailableDestinationsPolicy;
+        if (string.IsNullOrEmpty(availableDestinationsPolicy))
+        {
+            // The default.
+            availableDestinationsPolicy = HealthCheckConstants.AvailableDestinations.HealthyOrPanic;
+        }
+
+        if (!_availableDestinationsPolicies.ContainsKey(availableDestinationsPolicy))
+        {
+            errors.Add(new ArgumentException($"No matching {nameof(IAvailableDestinationsPolicy)} found for the available destinations policy '{availableDestinationsPolicy}' set on the cluster.'{cluster.ClusterId}'."));
+        }
+
+        ValidateActiveHealthCheck(cluster, errors);
+        ValidatePassiveHealthCheck(cluster, errors);
+
+        return ValueTask.CompletedTask;
+    }
+
+    private void ValidateActiveHealthCheck(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (!(cluster.HealthCheck?.Active?.Enabled ?? false))
+        {
+            // Active health check is disabled
+            return;
+        }
+
+        var activeOptions = cluster.HealthCheck.Active;
+        var policy = activeOptions.Policy;
+        if (string.IsNullOrEmpty(policy))
+        {
+            // default policy
+            policy = HealthCheckConstants.ActivePolicy.ConsecutiveFailures;
+        }
+        if (!_activeHealthCheckPolicies.ContainsKey(policy))
+        {
+            errors.Add(new ArgumentException($"No matching {nameof(IActiveHealthCheckPolicy)} found for the active health check policy name '{policy}' set on the cluster '{cluster.ClusterId}'."));
+        }
+
+        if (activeOptions.Interval is not null && activeOptions.Interval <= TimeSpan.Zero)
+        {
+            errors.Add(new ArgumentException($"Destination probing interval set on the cluster '{cluster.ClusterId}' must be positive."));
+        }
+
+        if (activeOptions.Timeout is not null && activeOptions.Timeout <= TimeSpan.Zero)
+        {
+            errors.Add(new ArgumentException($"Destination probing timeout set on the cluster '{cluster.ClusterId}' must be positive."));
+        }
+    }
+
+    private void ValidatePassiveHealthCheck(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (!(cluster.HealthCheck?.Passive?.Enabled ?? false))
+        {
+            // Passive health check is disabled
+            return;
+        }
+
+        var passiveOptions = cluster.HealthCheck.Passive;
+        var policy = passiveOptions.Policy;
+        if (string.IsNullOrEmpty(policy))
+        {
+            // default policy
+            policy = HealthCheckConstants.PassivePolicy.TransportFailureRate;
+        }
+        if (!_passiveHealthCheckPolicies.ContainsKey(policy))
+        {
+            errors.Add(new ArgumentException($"No matching {nameof(IPassiveHealthCheckPolicy)} found for the passive health check policy name '{policy}' set on the cluster '{cluster.ClusterId}'."));
+        }
+
+        if (passiveOptions.ReactivationPeriod is not null && passiveOptions.ReactivationPeriod <= TimeSpan.Zero)
+        {
+            errors.Add(new ArgumentException($"Unhealthy destination reactivation period set on the cluster '{cluster.ClusterId}' must be positive."));
+        }
+    }
+}

src/ReverseProxy/Configuration/ClusterValidators/IClusterValidator.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+/// <summary>
+/// Provides method to validate cluster configuration.
+/// </summary>
+public interface IClusterValidator
+{
+
+    /// <summary>
+    /// Perform validation on a cluster configuration by adding exceptions to the provided collection.
+    /// </summary>
+    /// <param name="cluster">Cluster configuration to validate</param>
+    /// <param name="errors">Collection of all validation exceptions</param>
+    /// <returns>A ValueTask representing the asynchronous validation operation.</returns>
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors);
+}

src/ReverseProxy/Configuration/ClusterValidators/LoadBalancingValidator.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Yarp.ReverseProxy.LoadBalancing;
+using Yarp.ReverseProxy.Utilities;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class LoadBalancingValidator : IClusterValidator
+{
+    private readonly FrozenDictionary<string, ILoadBalancingPolicy> _loadBalancingPolicies;
+    public LoadBalancingValidator(IEnumerable<ILoadBalancingPolicy> loadBalancingPolicies)
+    {
+        _loadBalancingPolicies = loadBalancingPolicies?.ToDictionaryByUniqueId(p => p.Name) ?? throw new ArgumentNullException(nameof(loadBalancingPolicies));
+    }
+
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        var loadBalancingPolicy = cluster.LoadBalancingPolicy;
+        if (string.IsNullOrEmpty(loadBalancingPolicy))
+        {
+            // The default.
+            loadBalancingPolicy = LoadBalancingPolicies.PowerOfTwoChoices;
+        }
+
+        if (!_loadBalancingPolicies.ContainsKey(loadBalancingPolicy))
+        {
+            errors.Add(new ArgumentException($"No matching {nameof(ILoadBalancingPolicy)} found for the load balancing policy '{loadBalancingPolicy}' set on the cluster '{cluster.ClusterId}'."));
+        }
+
+        return ValueTask.CompletedTask;
+    }
+}

src/ReverseProxy/Configuration/ClusterValidators/ProxyHttpClientValidator.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class ProxyHttpClientValidator : IClusterValidator
+{
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (cluster.HttpClient is null)
+        {
+            // Proxy http client options are not set.
+            return ValueTask.CompletedTask;
+        }
+
+        if (cluster.HttpClient.MaxConnectionsPerServer is not null && cluster.HttpClient.MaxConnectionsPerServer <= 0)
+        {
+            errors.Add(new ArgumentException($"Max connections per server limit set on the cluster '{cluster.ClusterId}' must be positive."));
+        }
+
+        var requestHeaderEncoding = cluster.HttpClient.RequestHeaderEncoding;
+        if (requestHeaderEncoding is not null)
+        {
+            try
+            {
+                Encoding.GetEncoding(requestHeaderEncoding);
+            }
+            catch (ArgumentException aex)
+            {
+                errors.Add(new ArgumentException($"Invalid request header encoding '{requestHeaderEncoding}'.", aex));
+            }
+        }
+
+        var responseHeaderEncoding = cluster.HttpClient.ResponseHeaderEncoding;
+        if (responseHeaderEncoding is null)
+        {
+            return ValueTask.CompletedTask;
+        }
+
+        try
+        {
+            Encoding.GetEncoding(responseHeaderEncoding);
+        }
+        catch (ArgumentException aex)
+        {
+            errors.Add(new ArgumentException($"Invalid response header encoding '{responseHeaderEncoding}'.", aex));
+        }
+
+        return ValueTask.CompletedTask;
+    }
+}

src/ReverseProxy/Configuration/ClusterValidators/ProxyHttpRequestValidator.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class ProxyHttpRequestValidator(ILogger<ConfigValidator> logger) : IClusterValidator
+{
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (cluster.HttpRequest is null)
+        {
+            // Proxy http request options are not set.
+            return ValueTask.CompletedTask;
+        }
+
+        if (cluster.HttpRequest.Version is not null &&
+            cluster.HttpRequest.Version != HttpVersion.Version10 &&
+            cluster.HttpRequest.Version != HttpVersion.Version11 &&
+            cluster.HttpRequest.Version != HttpVersion.Version20 &&
+            cluster.HttpRequest.Version != HttpVersion.Version30)
+        {
+            errors.Add(new ArgumentException($"Outgoing request version '{cluster.HttpRequest.Version}' is not any of supported HTTP versions (1.0, 1.1, 2 and 3)."));
+        }
+
+        if (cluster.HttpRequest.Version == HttpVersion.Version10)
+        {
+            Log.Http10Version(logger);
+        }
+
+        return ValueTask.CompletedTask;
+    }
+
+    private static class Log
+    {
+        private static readonly Action<ILogger, Exception?> _http10RequestVersionDetected = LoggerMessage.Define(
+            LogLevel.Warning,
+            EventIds.Http10RequestVersionDetected,
+            "The HttpRequest version is set to 1.0 which can result in poor performance and port exhaustion. Use 1.1, 2, or 3 instead.");
+
+        public static void Http10Version(ILogger logger)
+        {
+            _http10RequestVersionDetected(logger, null);
+        }
+    }
+}

src/ReverseProxy/Configuration/ClusterValidators/SessionAffinityValidator.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Collections.Frozen;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Yarp.ReverseProxy.SessionAffinity;
+using Yarp.ReverseProxy.Utilities;
+
+namespace Yarp.ReverseProxy.Configuration.ClusterValidators;
+
+internal sealed class SessionAffinityValidator : IClusterValidator
+{
+    private readonly FrozenDictionary<string, IAffinityFailurePolicy> _affinityFailurePolicies;
+
+    public SessionAffinityValidator(IEnumerable<IAffinityFailurePolicy> affinityFailurePolicies)
+    {
+        _affinityFailurePolicies = affinityFailurePolicies?.ToDictionaryByUniqueId(p => p.Name) ?? throw new ArgumentNullException(nameof(affinityFailurePolicies));
+    }
+
+    public ValueTask ValidateAsync(ClusterConfig cluster, IList<Exception> errors)
+    {
+        if (!(cluster.SessionAffinity?.Enabled ?? false))
+        {
+            // Session affinity is disabled
+            return ValueTask.CompletedTask;
+        }
+
+        // Note some affinity validation takes place in AffinitizeTransformProvider.ValidateCluster.
+        var affinityFailurePolicy = cluster.SessionAffinity.FailurePolicy;
+        if (string.IsNullOrEmpty(affinityFailurePolicy))
+        {
+            // The default.
+            affinityFailurePolicy = SessionAffinityConstants.FailurePolicies.Redistribute;
+        }
+
+        if (!_affinityFailurePolicies.ContainsKey(affinityFailurePolicy))
+        {
+            errors.Add(new ArgumentException($"No matching {nameof(IAffinityFailurePolicy)} found for the affinity failure policy name '{affinityFailurePolicy}' set on the cluster '{cluster.ClusterId}'."));
+        }
+
+        if (string.IsNullOrEmpty(cluster.SessionAffinity.AffinityKeyName))
+        {
+            errors.Add(new ArgumentException($"Affinity key name set on the cluster '{cluster.ClusterId}' must not be null."));
+        }
+
+        var cookieConfig = cluster.SessionAffinity.Cookie;
+
+        if (cookieConfig is null)
+        {
+            return ValueTask.CompletedTask;
+        }
+
+        if (cookieConfig.Expiration is not null && cookieConfig.Expiration <= TimeSpan.Zero)
+        {
+            errors.Add(new ArgumentException($"Session affinity cookie expiration must be positive or null."));
+        }
+
+        if (cookieConfig.MaxAge is not null && cookieConfig.MaxAge <= TimeSpan.Zero)
+        {
+            errors.Add(new ArgumentException($"Session affinity cookie max-age must be positive or null."));
+        }
+
+        return ValueTask.CompletedTask;
+    }
+}