Added Metrics rate limits (#3276)

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Metrics now honor any Rate Limits set in HTTP headers returned by Sentry ([#3276](https://github.com/getsentry/sentry-dotnet/pull/3276))
+
 ### Fixes
 
 - Fixed normalization for metric tag values for carriage return, line feed and tab characters ([#3281](https://github.com/getsentry/sentry-dotnet/pull/3281))

src/Sentry/Http/HttpTransportBase.cs

@@ -271,6 +271,12 @@ private void ExtractRateLimits(HttpHeaders responseHeaders)
         {
             foreach (var rateLimitCategory in rateLimit.Categories)
             {
+                if (string.Equals(rateLimitCategory.Name, "metric_bucket", StringComparison.OrdinalIgnoreCase)
+                    && !rateLimit.IsDefaultNamespace)
+                {
+                    // Currently we only back off for default/empty namespaces
+                    continue;
+                }
                 CategoryLimitResets[rateLimitCategory] = now + rateLimit.RetryAfter;
             }
         }

src/Sentry/Internal/Http/RateLimit.cs

@@ -4,14 +4,19 @@ internal class RateLimit
 {
     public IReadOnlyList<RateLimitCategory> Categories { get; }
 
+    public IReadOnlyList<string>? Namespaces { get; }
+
+    internal bool IsDefaultNamespace =>
+        Namespaces is null ||
+        (Namespaces.Count == 1 && string.Equals(Namespaces[0], "custom", StringComparison.OrdinalIgnoreCase));
+
     public TimeSpan RetryAfter { get; }
 
-    public RateLimit(
-        IReadOnlyList<RateLimitCategory> categories,
-        TimeSpan retryAfter)
+    public RateLimit(TimeSpan retryAfter, IReadOnlyList<RateLimitCategory> categories, IReadOnlyList<string>? namespaces = null)
     {
-        Categories = categories;
         RetryAfter = retryAfter;
+        Categories = categories;
+        Namespaces = namespaces;
     }
 
     public static RateLimit Parse(string rateLimitEncoded)
@@ -21,10 +26,20 @@ public static RateLimit Parse(string rateLimitEncoded)
 
         var retryAfter = TimeSpan.FromSeconds(int.Parse(components[0], CultureInfo.InvariantCulture));
         var categories = components[1].Split(';').Select(c => new RateLimitCategory(c)).ToArray();
+        string[]? namespaces = null;
+        foreach (var category in categories)
+        {
+            if (!string.Equals(category.Name, "metric_bucket", StringComparison.OrdinalIgnoreCase))
+            {
+                continue;
+            }
+
+            // Response header looking like this: X-Sentry-Rate-Limits: 2700:metric_bucket:organization:quota_exceeded:custom
+            namespaces = components.Length > 4 ? components[4].Split(';') : null;
+            break;
+        }
 
-        return new RateLimit(
-            categories,
-            retryAfter);
+        return new RateLimit(retryAfter, categories, namespaces);
     }
 
     public static IEnumerable<RateLimit> ParseMany(string rateLimitsEncoded) =>

src/Sentry/Internal/Http/RateLimitCategory.cs

@@ -23,7 +23,14 @@ public bool Matches(EnvelopeItem item)
             return false;
         }
 
-        return string.Equals(Name, type, StringComparison.OrdinalIgnoreCase);
+        return type switch
+        {
+            EnvelopeItem.TypeValueMetric =>
+                // Metrics are a bit unique - the envelope item type is `statsd` but the category is `metric_bucket`
+                string.Equals(Name, "metric_bucket", StringComparison.OrdinalIgnoreCase),
+            // For most reporting categories, the envelope item type matches the client report category
+            _ => string.Equals(Name, type, StringComparison.OrdinalIgnoreCase)
+        };
     }
 
     public bool Equals(RateLimitCategory? other)

src/Sentry/Protocol/Envelopes/EnvelopeItem.cs

@@ -12,16 +12,16 @@ public sealed class EnvelopeItem : ISerializable, IDisposable
 {
     private const string TypeKey = "type";
 
-    private const string TypeValueEvent = "event";
-    private const string TypeValueUserReport = "user_report";
-    private const string TypeValueTransaction = "transaction";
-    private const string TypeValueSession = "session";
-    private const string TypeValueCheckIn = "check_in";
-    private const string TypeValueAttachment = "attachment";
-    private const string TypeValueClientReport = "client_report";
-    private const string TypeValueProfile = "profile";
-    private const string TypeValueMetric = "statsd";
-    private const string TypeValueCodeLocations = "metric_meta";
+    internal const string TypeValueEvent = "event";
+    internal const string TypeValueUserReport = "user_report";
+    internal const string TypeValueTransaction = "transaction";
+    internal const string TypeValueSession = "session";
+    internal const string TypeValueCheckIn = "check_in";
+    internal const string TypeValueAttachment = "attachment";
+    internal const string TypeValueClientReport = "client_report";
+    internal const string TypeValueProfile = "profile";
+    internal const string TypeValueMetric = "statsd";
+    internal const string TypeValueCodeLocations = "metric_meta";
 
     private const string LengthKey = "length";
     private const string FileNameKey = "filename";

test/Sentry.Tests/Internals/Http/HttpTransportTests.cs

@@ -276,13 +276,17 @@ public async Task SendEnvelopeAsync_ResponseNotOkNoMessage_LogsError()
         ).Should().BeTrue();
     }
 
-    [Fact]
-    public async Task SendEnvelopeAsync_ItemRateLimit_DropsItem()
+    [Theory]
+    [InlineData("2700:metric_bucket:organization:quota_exceeded:custom", true)] // Default namespace... we back off
+    [InlineData("2700:metric_bucket:organization:quota_exceeded", true)] // No namespace... we back off
+    [InlineData("2700:metric_bucket:organization:", true)] // Empty namespace... we back off
+    [InlineData("2700:metric_bucket:organization:quota_exceeded:foo", false)] // Specific namespace... we don't back off for these yet
+    public async Task SendEnvelopeAsync_ItemRateLimit_DropsItem(string metricNamespace, bool shouldDropMetricEnvelope)
     {
         // Arrange
         using var httpHandler = new RecordingHttpMessageHandler(
             new FakeHttpMessageHandler(
-                () => SentryResponses.GetRateLimitResponse("1234:event, 897:transaction")
+                () => SentryResponses.GetRateLimitResponse($"1234:event, 897:transaction, {metricNamespace}")
             ));
 
         var httpTransport = new HttpTransport(
@@ -305,29 +309,43 @@ public async Task SendEnvelopeAsync_ItemRateLimit_DropsItem()
             {
                 // Should be dropped
                 new EnvelopeItem(
-                    new Dictionary<string, object> {["type"] = "event"},
+                    new Dictionary<string, object> {["type"] = EnvelopeItem.TypeValueEvent},
                     new EmptySerializable()),
                 new EnvelopeItem(
-                    new Dictionary<string, object> {["type"] = "event"},
+                    new Dictionary<string, object> {["type"] = EnvelopeItem.TypeValueEvent},
                     new EmptySerializable()),
                 new EnvelopeItem(
-                    new Dictionary<string, object> {["type"] = "transaction"},
+                    new Dictionary<string, object> {["type"] = EnvelopeItem.TypeValueTransaction},
                     new EmptySerializable()),
 
                 // Should stay
                 new EnvelopeItem(
                     new Dictionary<string, object> {["type"] = "other"},
-                    new EmptySerializable())
+                    new EmptySerializable()),
+
+                // Dropped if metricNamespace is "custom" or empty
+                new EnvelopeItem(
+                    new Dictionary<string, object> {["type"] = EnvelopeItem.TypeValueMetric},
+                    new EmptySerializable()),
             });
 
+        var expectedItems = new List<EnvelopeItem>
+        {
+            new EnvelopeItem(
+                new Dictionary<string, object> {["type"] = "other"},
+                new EmptySerializable())
+        };
+        if (!shouldDropMetricEnvelope)
+        {
+            expectedItems.Add(
+                new EnvelopeItem(
+                    new Dictionary<string, object> { ["type"] = EnvelopeItem.TypeValueMetric },
+                    new EmptySerializable()));
+        }
         var expectedEnvelope = new Envelope(
             new Dictionary<string, object>(),
-            new[]
-            {
-                new EnvelopeItem(
-                    new Dictionary<string, object> {["type"] = "other"},
-                    new EmptySerializable())
-            });
+            expectedItems
+        );
 
         var expectedEnvelopeSerialized = await expectedEnvelope.SerializeToStringAsync(_testOutputLogger, _fakeClock);
 

test/Sentry.Tests/Internals/Http/RateLimitCategoryTests.cs

@@ -5,13 +5,15 @@ namespace Sentry.Tests.Internals.Http;
 public class RateLimitCategoryTests
 {
     [Theory]
-    [InlineData("event", "event")]
-    [InlineData("session", "session")]
-    [InlineData("transaction", "transaction")]
-    [InlineData("attachment", "attachment")]
-    [InlineData("", "event")]
-    [InlineData("", "session")]
-    [InlineData("", "transaction")]
+    [InlineData("event", EnvelopeItem.TypeValueEvent)]
+    [InlineData("metric_bucket", EnvelopeItem.TypeValueMetric)]
+    [InlineData("session", EnvelopeItem.TypeValueSession)]
+    [InlineData("transaction", EnvelopeItem.TypeValueTransaction)]
+    [InlineData("attachment", EnvelopeItem.TypeValueAttachment)]
+    [InlineData("", EnvelopeItem.TypeValueEvent)]
+    [InlineData("", EnvelopeItem.TypeValueMetric)]
+    [InlineData("", EnvelopeItem.TypeValueSession)]
+    [InlineData("", EnvelopeItem.TypeValueTransaction)]
     public void Matches_IncludedItemType_ShouldMatch(string categoryName, string itemType)
     {
         // Arrange
@@ -29,9 +31,10 @@ public void Matches_IncludedItemType_ShouldMatch(string categoryName, string ite
     }
 
     [Theory]
-    [InlineData("event", "transaction")]
-    [InlineData("error", "attachment")]
-    [InlineData("session", "event")]
+    [InlineData("event", EnvelopeItem.TypeValueTransaction)]
+    [InlineData("error", EnvelopeItem.TypeValueAttachment)]
+    [InlineData("session", EnvelopeItem.TypeValueEvent)]
+    [InlineData("metric_bucket", EnvelopeItem.TypeValueSession)]
     public void Matches_NotIncludedItemType_ShouldNotMatch(string categoryName, string itemType)
     {
         // Arrange

test/Sentry.Tests/Internals/Http/RateLimitTests.cs

@@ -14,10 +14,7 @@ public void Parse_MinimalFormat_Works()
         var rateLimit = RateLimit.Parse(value);
 
         // Assert
-        rateLimit.Should().BeEquivalentTo(new RateLimit(
-            new[] { new RateLimitCategory("transaction") },
-            TimeSpan.FromSeconds(60)
-        ));
+        rateLimit.Should().BeEquivalentTo(new RateLimit(TimeSpan.FromSeconds(60), new[] { new RateLimitCategory("transaction") }));
     }
 
     [Fact]
@@ -30,10 +27,7 @@ public void Parse_MinimalFormat_EmptyCatgetory_Works()
         var rateLimit = RateLimit.Parse(value);
 
         // Assert
-        rateLimit.Should().BeEquivalentTo(new RateLimit(
-            new[] { new RateLimitCategory("") },
-            TimeSpan.FromSeconds(60)
-        ));
+        rateLimit.Should().BeEquivalentTo(new RateLimit(TimeSpan.FromSeconds(60), new[] { new RateLimitCategory("") }));
     }
 
     [Fact]
@@ -46,10 +40,7 @@ public void Parse_MinimalFormat_EmptyCategory_IgnoresScope()
         var rateLimit = RateLimit.Parse(value);
 
         // Assert
-        rateLimit.Should().BeEquivalentTo(new RateLimit(
-            new[] { new RateLimitCategory("") },
-            TimeSpan.FromSeconds(60)
-        ));
+        rateLimit.Should().BeEquivalentTo(new RateLimit(TimeSpan.FromSeconds(60), new[] { new RateLimitCategory("") }));
     }
 
     [Fact]
@@ -62,10 +53,7 @@ public void Parse_FullFormat_Works()
         var rateLimit = RateLimit.Parse(value);
 
         // Assert
-        rateLimit.Should().BeEquivalentTo(new RateLimit(
-            new[] { new RateLimitCategory("transaction") },
-            TimeSpan.FromSeconds(60)
-        ));
+        rateLimit.Should().BeEquivalentTo(new RateLimit(TimeSpan.FromSeconds(60), new[] { new RateLimitCategory("transaction") }));
     }
 
     [Fact]
@@ -77,15 +65,62 @@ public void Parse_MultipleCategories_Works()
         // Act
         var rateLimit = RateLimit.Parse(value);
 
+        // Assert
+        rateLimit.Should().BeEquivalentTo(new RateLimit(TimeSpan.FromSeconds(2700), new[]
+        {
+            new RateLimitCategory("default"),
+            new RateLimitCategory("error"),
+            new RateLimitCategory("security")
+        }));
+    }
+
+    [Fact]
+    public void Parse_SingleNamespace_Works()
+    {
+        // Arrange
+        const string value = "2700:metric_bucket:organization:quota_exceeded:custom";
+
+        // Act
+        var rateLimit = RateLimit.Parse(value);
+
+        // Assert
+        rateLimit.Should().BeEquivalentTo(new RateLimit(
+            TimeSpan.FromSeconds(2700),
+            [new RateLimitCategory("metric_bucket")],
+            ["custom"]
+        ));
+    }
+
+    [Fact]
+    public void Parse_MultipleNamespaces_Works()
+    {
+        // Arrange
+        const string value = "2700:metric_bucket:organization:quota_exceeded:apples;oranges;pears";
+
+        // Act
+        var rateLimit = RateLimit.Parse(value);
+
+        // Assert
+        rateLimit.Should().BeEquivalentTo(new RateLimit(
+            TimeSpan.FromSeconds(2700),
+            [new RateLimitCategory("metric_bucket")],
+            ["apples", "oranges", "pears"]
+        ));
+    }
+
+    [Fact]
+    public void Parse_NotMetricBucket_NamespacesIgnored()
+    {
+        // Arrange
+        const string value = "2700:default:organization:quota_exceeded:custom";
+
+        // Act
+        var rateLimit = RateLimit.Parse(value);
+
         // Assert
         rateLimit.Should().BeEquivalentTo(new RateLimit(
-            new[]
-            {
-                new RateLimitCategory("default"),
-                new RateLimitCategory("error"),
-                new RateLimitCategory("security")
-            },
-            TimeSpan.FromSeconds(2700)
+            TimeSpan.FromSeconds(2700),
+            [new RateLimitCategory("default")]
         ));
     }
 }