Generalized RateLimit logic to all indexers based on indexer id

Fixes #1982

Co-authored-by: Taloth Saldono <Taloth@users.noreply.github.com>

src/NzbDrone.Common.Test/TPLTests/RateLimitServiceFixture.cs

@@ -89,5 +89,38 @@ namespace NzbDrone.Common.Test.TPLTests
 
             (GetRateLimitStore()["me"] - _epoch).Should().BeGreaterOrEqualTo(TimeSpan.FromMilliseconds(100));
         }
+
+        [Test]
+        public void should_extend_subkey_delay()
+        {
+            GivenExisting("me", _epoch + TimeSpan.FromMilliseconds(200));
+            GivenExisting("me-sub", _epoch + TimeSpan.FromMilliseconds(300));
+
+            Subject.WaitAndPulse("me", "sub", TimeSpan.FromMilliseconds(100));
+
+            (GetRateLimitStore()["me-sub"] - _epoch).Should().BeGreaterOrEqualTo(TimeSpan.FromMilliseconds(400));
+        }
+
+        [Test]
+        public void should_honor_basekey_delay()
+        {
+            GivenExisting("me", _epoch + TimeSpan.FromMilliseconds(200));
+            GivenExisting("me-sub", _epoch + TimeSpan.FromMilliseconds(0));
+
+            Subject.WaitAndPulse("me", "sub", TimeSpan.FromMilliseconds(100));
+
+            (GetRateLimitStore()["me-sub"] - _epoch).Should().BeGreaterOrEqualTo(TimeSpan.FromMilliseconds(200));
+        }
+
+        [Test]
+        public void should_not_extend_basekey_delay()
+        {
+            GivenExisting("me", _epoch + TimeSpan.FromMilliseconds(200));
+            GivenExisting("me-sub", _epoch + TimeSpan.FromMilliseconds(100));
+
+            Subject.WaitAndPulse("me", "sub", TimeSpan.FromMilliseconds(100));
+
+            (GetRateLimitStore()["me"] - _epoch).Should().BeCloseTo(TimeSpan.FromMilliseconds(200));
+        }
     }
 }

src/NzbDrone.Common/Http/HttpClient.cs

@@ -112,7 +112,7 @@ namespace NzbDrone.Common.Http
 
             if (request.RateLimit != TimeSpan.Zero)
             {
-                _rateLimitService.WaitAndPulse(request.Url.Host, request.RateLimit);
+                _rateLimitService.WaitAndPulse(request.Url.Host, request.RateLimitKey, request.RateLimit);
             }
 
             _logger.Trace(request);

src/NzbDrone.Common/Http/HttpRequest.cs

@@ -47,6 +47,7 @@ namespace NzbDrone.Common.Http
         public bool StoreResponseCookie { get; set; }
         public TimeSpan RequestTimeout { get; set; }
         public TimeSpan RateLimit { get; set; }
+        public string RateLimitKey { get; set; }
 
         public override string ToString()
         {

src/NzbDrone.Common/TPL/RateLimitService.cs

@@ -2,12 +2,14 @@
 using System.Collections.Concurrent;
 using NLog;
 using NzbDrone.Common.Cache;
+using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Common.TPL
 {
     public interface IRateLimitService
     {
         void WaitAndPulse(string key, TimeSpan interval);
+        void WaitAndPulse(string key, string subKey, TimeSpan interval);
     }
 
     public class RateLimitService : IRateLimitService
@@ -23,9 +25,37 @@ namespace NzbDrone.Common.TPL
 
         public void WaitAndPulse(string key, TimeSpan interval)
         {
-            var waitUntil = _rateLimitStore.AddOrUpdate(key,
-                (s) => DateTime.UtcNow + interval,
-                (s, i) => new DateTime(Math.Max(DateTime.UtcNow.Ticks, i.Ticks), DateTimeKind.Utc) + interval);
+            WaitAndPulse(key, null, interval);
+        }
+
+        public void WaitAndPulse(string key, string subKey, TimeSpan interval)
+        {
+            var waitUntil = DateTime.UtcNow.Add(interval);
+
+            if (subKey.IsNotNullOrWhiteSpace())
+            {
+                // Expand the base key timer, but don't extend it beyond now+interval.
+                var baseUntil = _rateLimitStore.AddOrUpdate(key,
+                    (s) => waitUntil,
+                    (s, i) => new DateTime(Math.Max(waitUntil.Ticks, i.Ticks), DateTimeKind.Utc));
+
+                if (baseUntil > waitUntil)
+                {
+                    waitUntil = baseUntil;
+                }
+
+                // Wait for the full key
+                var combinedKey = key + "-" + subKey;
+                waitUntil = _rateLimitStore.AddOrUpdate(combinedKey,
+                    (s) => waitUntil,
+                    (s, i) => new DateTime(Math.Max(waitUntil.Ticks, i.Add(interval).Ticks), DateTimeKind.Utc));
+            }
+            else
+            {
+                waitUntil = _rateLimitStore.AddOrUpdate(key,
+                    (s) => waitUntil,
+                    (s, i) => new DateTime(Math.Max(waitUntil.Ticks, i.Add(interval).Ticks), DateTimeKind.Utc));
+            }
 
             waitUntil -= interval;
 

src/NzbDrone.Core/Download/TorrentClientBase.cs

@@ -128,6 +128,7 @@ namespace NzbDrone.Core.Download
             try
             {
                 var request = new HttpRequest(torrentUrl);
+                request.RateLimitKey = remoteAlbum?.Release?.IndexerId.ToString();
                 request.Headers.Accept = "application/x-bittorrent";
                 request.AllowAutoRedirect = false;
 

src/NzbDrone.Core/Download/UsenetClientBase.cs

@@ -45,6 +45,7 @@ namespace NzbDrone.Core.Download
             try
             {
                 var nzbDataRequest = new HttpRequest(url);
+                nzbDataRequest.RateLimitKey = remoteAlbum?.Release?.IndexerId.ToString();
 
                 // TODO: Look into moving download request handling to indexer
                 if (remoteAlbum.Release.BasicAuthString.IsNotNullOrWhiteSpace())

src/NzbDrone.Core/Indexers/HttpIndexerBase.cs

@@ -280,6 +280,8 @@ namespace NzbDrone.Core.Indexers
                 request.HttpRequest.RateLimit = RateLimit;
             }
 
+            request.HttpRequest.RateLimitKey = Definition.Id.ToString();
+
             return new IndexerResponse(request, _httpClient.Execute(request.HttpRequest));
         }