Rate Policy

Libraries/Esiur/Resource/Attributes/AutoDeliveryAttribute.cs

@@ -38,6 +38,8 @@ namespace Esiur.Resource;
     AttributeTargets.Field,
     AllowMultiple = false,
     Inherited = true)]
-public sealed class AutoDeliveredAttribute : Attribute
+public class AutoDeliveryAttribute : Attribute
 {
-}
+
+}
+

Libraries/Esiur/Resource/Attributes/DefinitionMetadataAttributes.cs

@@ -0,0 +1,163 @@
+using Esiur.Data.Types;
+using System;
+
+namespace Esiur.Resource;
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface |
+    AttributeTargets.Enum | AttributeTargets.Method | AttributeTargets.Property |
+    AttributeTargets.Field | AttributeTargets.Event | AttributeTargets.Parameter,
+    AllowMultiple = false, Inherited = true)]
+public sealed class DescriptionAttribute : Attribute
+{
+    public string Value { get; }
+
+    public DescriptionAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface |
+    AttributeTargets.Enum | AttributeTargets.Method | AttributeTargets.Property |
+    AttributeTargets.Field | AttributeTargets.Event | AttributeTargets.Parameter,
+    AllowMultiple = true, Inherited = true)]
+public sealed class ExampleAttribute : Attribute
+{
+    public object Value { get; }
+
+    public ExampleAttribute(object value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct |
+    AttributeTargets.Interface | AttributeTargets.Enum,
+    AllowMultiple = false, Inherited = true)]
+public sealed class CategoryAttribute : Attribute
+{
+    public string Value { get; }
+
+    public CategoryAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct |
+    AttributeTargets.Interface | AttributeTargets.Enum,
+    AllowMultiple = false, Inherited = true)]
+public sealed class SinceAttribute : Attribute
+{
+    public string Value { get; }
+
+    public SinceAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property |
+    AttributeTargets.Field | AttributeTargets.Event,
+    AllowMultiple = false, Inherited = true)]
+public sealed class TagsAttribute : Attribute
+{
+    public string[] Values { get; }
+
+    public TagsAttribute(params string[] values) => Values = values;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Method | AttributeTargets.Event,
+    AllowMultiple = false, Inherited = true)]
+public sealed class UnitAttribute : Attribute
+{
+    public string Value { get; }
+
+    public UnitAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Parameter,
+    AllowMultiple = false, Inherited = true)]
+public sealed class MinimumAttribute : Attribute
+{
+    public object Value { get; }
+
+    public MinimumAttribute(object value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Parameter,
+    AllowMultiple = false, Inherited = true)]
+public sealed class MaximumAttribute : Attribute
+{
+    public object Value { get; }
+
+    public MaximumAttribute(object value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Parameter,
+    AllowMultiple = true, Inherited = true)]
+public sealed class AllowedValueAttribute : Attribute
+{
+    public object Value { get; }
+
+    public AllowedValueAttribute(object value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Parameter,
+    AllowMultiple = false, Inherited = true)]
+public sealed class PatternAttribute : Attribute
+{
+    public string Value { get; }
+
+    public PatternAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
+    AttributeTargets.Method | AttributeTargets.Event | AttributeTargets.Parameter,
+    AllowMultiple = false, Inherited = true)]
+public sealed class FormatAttribute : Attribute
+{
+    public string Value { get; }
+
+    public FormatAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method,
+    AllowMultiple = true, Inherited = true)]
+public sealed class PreconditionAttribute : Attribute
+{
+    public string Value { get; }
+
+    public PreconditionAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method,
+    AllowMultiple = true, Inherited = true)]
+public sealed class PostconditionAttribute : Attribute
+{
+    public string Value { get; }
+
+    public PostconditionAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method,
+    AllowMultiple = false, Inherited = true)]
+public sealed class EffectsAttribute : Attribute
+{
+    public OperationEffects Value { get; }
+
+    public EffectsAttribute(OperationEffects value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property |
+    AttributeTargets.Field | AttributeTargets.Event,
+    AllowMultiple = true, Inherited = true)]
+public sealed class WarningAttribute : Attribute
+{
+    public string Value { get; }
+
+    public WarningAttribute(string value) => Value = value;
+}
+
+[AttributeUsage(AttributeTargets.Method | AttributeTargets.Property |
+    AttributeTargets.Field | AttributeTargets.Event,
+    AllowMultiple = false, Inherited = true)]
+public sealed class RelatedMembersAttribute : Attribute
+{
+    public byte[] Indexes { get; }
+
+    public RelatedMembersAttribute(params byte[] indexes) => Indexes = indexes;
+}

Libraries/Esiur/Resource/Attributes/HistoricalAttribute.cs

@@ -5,12 +5,13 @@ using System.Text;
 namespace Esiur.Resource
 {
     /// <summary>
-    /// Indicates that previous values of an exported property are retained
+    /// Indicates that previous property values or event occurrences are retained
     /// and may be fetched remotely.
     /// </summary>
     [AttributeUsage(
         AttributeTargets.Property |
-        AttributeTargets.Field,
+        AttributeTargets.Field |
+        AttributeTargets.Event,
         AllowMultiple = false,
         Inherited = true)]
     public sealed class HistoricalAttribute : Attribute

Libraries/Esiur/Resource/Attributes/RateControlAttribute.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace Esiur.Resource;
+
+/// <summary>
+/// Applies a named Warehouse rate policy to an exported function or property setter.
+/// </summary>
+[AttributeUsage(
+    AttributeTargets.Method | AttributeTargets.Property,
+    AllowMultiple = false,
+    Inherited = true)]
+public sealed class RateControlAttribute : Attribute
+{
+    /// <summary>
+    /// Gets the name used to resolve the policy from the owning Warehouse.
+    /// </summary>
+    public string PolicyName { get; }
+
+    public RateControlAttribute(string policyName)
+    {
+        if (string.IsNullOrWhiteSpace(policyName))
+            throw new ArgumentException("A rate policy name is required.", nameof(policyName));
+
+        PolicyName = policyName;
+    }
+}

Libraries/Esiur/Resource/Attributes/StreamAttribute.cs

@@ -6,7 +6,9 @@ using System.Text;
 namespace Esiur.Resource
 {
     /// <summary>
-    /// Marks an exported function as streaming and specifies its delivery mode.
+    /// Marks an AsyncReply-returning exported function as streaming and specifies
+    /// its delivery mode. IEnumerable and IAsyncEnumerable return types infer push
+    /// and pull mode respectively and do not require this attribute.
     /// </summary>
     [AttributeUsage(
         AttributeTargets.Method,

Libraries/Esiur/Resource/Attributes/UsageAttribute.cs

@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Esiur.Resource.Attributes
+namespace Esiur.Resource
 {
     [AttributeUsage(
             AttributeTargets.Class |

Libraries/Esiur/Resource/Attributes/VolatileAttribute.cs

@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Esiur.Resource.Attributes
+namespace Esiur.Resource
 {
     /// <summary>
     /// Indicates that an exported property has volatile synchronization

Libraries/Esiur/Resource/Warehouse.cs

@@ -31,6 +31,7 @@ using Esiur.Protocol;
 using Esiur.Proxy;
 using Esiur.Security.Authority;
 using Esiur.Security.Permissions;
+using Esiur.Security.RateLimiting;
 using Org.BouncyCastle.Asn1.Cms;
 using System;
 using System.Collections;
@@ -88,6 +89,8 @@ public class Warehouse
 
     Map<string, IAuthenticationProvider> _authenticationProviders = new Map<string, IAuthenticationProvider>();
     List<IPermissionsManager> _permissionsManagers = new List<IPermissionsManager>();
+    readonly ConcurrentDictionary<string, RatePolicy> _ratePolicies
+        = new ConcurrentDictionary<string, RatePolicy>(StringComparer.Ordinal);
 
 
     object _typeDefsLock = new object();
@@ -102,6 +105,11 @@ public class Warehouse
 
     public KeyList<string, ProtocolInstance> Protocols { get; } = new KeyList<string, ProtocolInstance>();
 
+    /// <summary>
+    /// Runtime settings for this Warehouse.
+    /// </summary>
+    public WarehouseConfiguration Configuration { get; }
+
     private Regex urlRegex = new Regex(@"^(?:([\S]*)://([^/]*)/?)");
 
 
@@ -121,6 +129,41 @@ public class Warehouse
         _permissionsManagers.Add(manager);
     }
 
+    /// <summary>
+    /// Registers a named rate policy referenced by RateControl attributes.
+    /// </summary>
+    public void AddRatePolicy(RatePolicy policy)
+    {
+        if (policy == null)
+            throw new ArgumentNullException(nameof(policy));
+        if (string.IsNullOrWhiteSpace(policy.Name))
+            throw new ArgumentException("The rate policy must have a name.", nameof(policy));
+        if (!_ratePolicies.TryAdd(policy.Name, policy))
+            throw new InvalidOperationException($"A rate policy named `{policy.Name}` is already registered.");
+    }
+
+    /// <summary>
+    /// Registers a policy under the supplied name.
+    /// </summary>
+    public void AddRatePolicy(string name, RatePolicy policy)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+            throw new ArgumentException("A rate policy name is required.", nameof(name));
+        if (policy == null)
+            throw new ArgumentNullException(nameof(policy));
+
+        policy.Name = name;
+        AddRatePolicy(policy);
+    }
+
+    public RatePolicy? TryGetRatePolicy(string name)
+        => !string.IsNullOrWhiteSpace(name) && _ratePolicies.TryGetValue(name, out var policy)
+            ? policy
+            : null;
+
+    public bool RemoveRatePolicy(string name)
+        => !string.IsNullOrWhiteSpace(name) && _ratePolicies.TryRemove(name, out _);
+
     public IAuthenticationProvider GetAuthenticationProvider(string name)
     {
         if (_authenticationProviders.ContainsKey(name))
@@ -137,8 +180,14 @@ public class Warehouse
     }
 
 
-    public Warehouse()
+    public Warehouse() : this(new WarehouseConfiguration())
     {
+    }
+
+    public Warehouse(WarehouseConfiguration configuration)
+    {
+        Configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
+
         Protocols.Add("EP",
             async (name, context)
             => await New<EpConnection>(name, context));

Libraries/Esiur/Resource/WarehouseConfiguration.cs

@@ -0,0 +1,33 @@
+using System;
+
+namespace Esiur.Resource;
+
+/// <summary>
+/// Runtime configuration owned by a Warehouse instance.
+/// </summary>
+public sealed class WarehouseConfiguration
+{
+    public RateControlConfiguration RateControl { get; set; } = new RateControlConfiguration();
+}
+
+/// <summary>
+/// Configures how repeated rate-control denials affect an EP connection.
+/// </summary>
+public sealed class RateControlConfiguration
+{
+    /// <summary>
+    /// Number of denials within <see cref="DenialWindow"/> that blocks the connection.
+    /// Set to zero to disable connection blocking.
+    /// </summary>
+    public int DenialsBeforeConnectionBlock { get; set; } = 5;
+
+    /// <summary>
+    /// Window in which denials are accumulated for connection blocking.
+    /// </summary>
+    public TimeSpan DenialWindow { get; set; } = TimeSpan.FromMinutes(1);
+
+    /// <summary>
+    /// Delay before a blocked connection is closed, allowing its final error reply to flush.
+    /// </summary>
+    public TimeSpan ConnectionBlockDelay { get; set; } = TimeSpan.FromMilliseconds(100);
+}