Add default Retry-After value

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- Use a default value of 60 seconds if a `Retry-After` header is not present. ([#1537](https://github.com/getsentry/sentry-dotnet/pull/1537))
+
 ## 3.15.0
 
 ### Features

src/Sentry/Internal/Http/RetryAfterHandler.cs

@@ -19,6 +19,7 @@ internal class RetryAfterHandler : DelegatingHandler
         private readonly ISystemClock _clock;
 
         private const HttpStatusCode TooManyRequests = (HttpStatusCode)429;
+        internal static readonly TimeSpan DefaultRetryAfterDelay = TimeSpan.FromSeconds(60);
 
         private long _retryAfterUtcTicks;
         internal long RetryAfterUtcTicks => _retryAfterUtcTicks;
@@ -63,31 +64,43 @@ protected override async Task<HttpResponseMessage> SendAsync(
 
             var response = await base.SendAsync(request, cancellationToken).ConfigureAwait(false);
 
-            if (response.StatusCode == TooManyRequests && response.Headers != null)
+            if (response.StatusCode == TooManyRequests)
+            {
+                var retryAfterTimestamp = GetRetryAfterTimestamp(response);
+                _ = Interlocked.Exchange(ref _retryAfterUtcTicks, retryAfterTimestamp.UtcTicks);
+            }
+
+            return response;
+        }
+
+        private DateTimeOffset GetRetryAfterTimestamp(HttpResponseMessage response)
+        {
+            if (response.Headers != null)
             {
                 if (response.Headers.RetryAfter != null)
                 {
-                    if (response.Headers.RetryAfter.Delta != null)
+                    if (response.Headers.RetryAfter.Delta is { } delta)
                     {
-                        var retryAfterUtc = _clock.GetUtcNow() + response.Headers.RetryAfter.Delta.Value;
-                        _ = Interlocked.Exchange(ref _retryAfterUtcTicks, retryAfterUtc.UtcTicks);
+                        return _clock.GetUtcNow() + delta;
                     }
-                    else if (response.Headers.RetryAfter.Date != null)
+
+                    if (response.Headers.RetryAfter.Date is { } date)
                     {
-                        _ = Interlocked.Exchange(ref _retryAfterUtcTicks, response.Headers.RetryAfter.Date.Value.UtcTicks);
+                        return date;
                     }
                 }
+
                 // Sentry was sending floating point numbers which are not handled by RetryConditionHeaderValue
                 // To be compatible with older versions of sentry on premise: https://github.com/getsentry/sentry/issues/7919
-                else if (response.Headers.TryGetValues("Retry-After", out var values)
-                         && double.TryParse(values?.FirstOrDefault(), out var retryAfterSeconds))
+                if (response.Headers.TryGetValues("Retry-After", out var values)
+                    && double.TryParse(values?.FirstOrDefault(), out var retryAfterSeconds))
                 {
-                    var retryAfterSpan = TimeSpan.FromSeconds(retryAfterSeconds);
-                    _ = Interlocked.Exchange(ref _retryAfterUtcTicks, _clock.GetUtcNow().AddTicks(retryAfterSpan.Ticks).UtcTicks);
+                    return _clock.GetUtcNow().AddTicks((long)(retryAfterSeconds * TimeSpan.TicksPerSecond));
                 }
             }
 
-            return response;
+            // No retry header was sent. Use the default retry delay.
+            return _clock.GetUtcNow() + DefaultRetryAfterDelay;
         }
     }
 }

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

@@ -54,7 +54,7 @@ public async Task SendAsync_TooManyRequestsWithoutRetryAfterHeader_RetryAfterNot
         var actual = await invoker.SendAsync(new HttpRequestMessage(HttpMethod.Get, "/"), None);
 
         Assert.Equal(expected, actual);
-        Assert.Equal(0, _fixture.Sut.RetryAfterUtcTicks);
+        Assert.Equal((_fixture.TimeReturned + RetryAfterHandler.DefaultRetryAfterDelay).UtcTicks, _fixture.Sut.RetryAfterUtcTicks);
         Assert.True(_fixture.StubHandler.SendAsyncCalled);
     }
 
@@ -104,7 +104,8 @@ public async Task SendAsync_TooManyRequestsWithRetryAfterHeaderFloat_RetryAfterS
         var actual = await invoker.SendAsync(new HttpRequestMessage(HttpMethod.Get, "/"), None);
 
         Assert.Equal(expected, actual);
-        Assert.Equal((_fixture.TimeReturned + TimeSpan.FromSeconds(floating)).UtcTicks, _fixture.Sut.RetryAfterUtcTicks);
+        var expectedTime = _fixture.TimeReturned.AddTicks((long)(floating * TimeSpan.TicksPerSecond));
+        Assert.Equal(expectedTime.UtcTicks, _fixture.Sut.RetryAfterUtcTicks);
         Assert.True(_fixture.StubHandler.SendAsyncCalled);
     }
 
@@ -127,7 +128,8 @@ public async Task SendAsync_TooManyRequestsWithRetryAfterHeaderFloat_SecondReque
         var actual = await invoker.SendAsync(new HttpRequestMessage(HttpMethod.Get, "/"), None);
 
         Assert.Equal(TooManyRequests, actual.StatusCode);
-        Assert.Equal((_fixture.TimeReturned + TimeSpan.FromSeconds(floating)).UtcTicks, _fixture.Sut.RetryAfterUtcTicks);
+        var expectedTime = _fixture.TimeReturned.AddTicks((long)(floating * TimeSpan.TicksPerSecond));
+        Assert.Equal(expectedTime.UtcTicks, _fixture.Sut.RetryAfterUtcTicks);
         Assert.False(_fixture.StubHandler.SendAsyncCalled);
     }