fix(core): Record byte discards for event processor drops

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixes
 
+- Record byte-level client reports when event processors discard logs or trace metrics ([#5718](https://github.com/getsentry/sentry-java/pull/5718))
 - Name the device-info caching thread `SentryDeviceInfoCache` so all threads spawned by the SDK are identifiable ([#5684](https://github.com/getsentry/sentry-java/pull/5684))
 
 ## 8.47.0

sentry/src/main/java/io/sentry/SentryClient.java

@@ -511,6 +511,7 @@ private SentryEvent processEvent(
   private SentryLogEvent processLogEvent(
       @NotNull SentryLogEvent event, final @NotNull List<EventProcessor> eventProcessors) {
     for (final EventProcessor processor : eventProcessors) {
+      final @NotNull SentryLogEvent eventBeforeProcessor = event;
       try {
         event = processor.process(event);
       } catch (Throwable e) {
@@ -533,6 +534,13 @@ private SentryLogEvent processLogEvent(
         options
             .getClientReportRecorder()
             .recordLostEvent(DiscardReason.EVENT_PROCESSOR, DataCategory.LogItem);
+        final long logEventNumberOfBytes =
+            JsonSerializationUtils.byteSizeOf(
+                options.getSerializer(), options.getLogger(), eventBeforeProcessor);
+        options
+            .getClientReportRecorder()
+            .recordLostEvent(
+                DiscardReason.EVENT_PROCESSOR, DataCategory.LogByte, logEventNumberOfBytes);
         break;
       }
     }
@@ -545,6 +553,7 @@ private SentryMetricsEvent processMetricsEvent(
       final @NotNull List<EventProcessor> eventProcessors,
       final @NotNull Hint hint) {
     for (final EventProcessor processor : eventProcessors) {
+      final @NotNull SentryMetricsEvent eventBeforeProcessor = event;
       try {
         event = processor.process(event, hint);
       } catch (Throwable e) {
@@ -567,6 +576,15 @@ private SentryMetricsEvent processMetricsEvent(
         options
             .getClientReportRecorder()
             .recordLostEvent(DiscardReason.EVENT_PROCESSOR, DataCategory.TraceMetric);
+        final long metricsEventNumberOfBytes =
+            JsonSerializationUtils.byteSizeOf(
+                options.getSerializer(), options.getLogger(), eventBeforeProcessor);
+        options
+            .getClientReportRecorder()
+            .recordLostEvent(
+                DiscardReason.EVENT_PROCESSOR,
+                DataCategory.TraceMetricByte,
+                metricsEventNumberOfBytes);
         break;
       }
     }

sentry/src/test/java/io/sentry/SentryClientTest.kt

@@ -33,6 +33,7 @@ import io.sentry.test.injectForField
 import io.sentry.transport.ITransport
 import io.sentry.transport.ITransportGate
 import io.sentry.util.HintUtils
+import io.sentry.util.JsonSerializationUtils
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
 import java.io.File
@@ -341,6 +342,39 @@ class SentryClientTest {
     )
   }
 
+  @Test
+  fun `when log is dropped by event processor, log byte discard is recorded`() {
+    val scope = createScope()
+    val logEvent = SentryLogEvent(SentryId(), SentryNanotimeDate(), "message", SentryLogLevel.WARN)
+    val logEventNumberOfBytes =
+      JsonSerializationUtils.byteSizeOf(
+        fixture.sentryOptions.serializer,
+        fixture.sentryOptions.logger,
+        logEvent,
+      )
+    scope.addEventProcessor(
+      object : EventProcessor {
+        override fun process(event: SentryLogEvent): SentryLogEvent? = null
+      }
+    )
+
+    val sut = fixture.getSut()
+    sut.captureLog(logEvent, scope)
+
+    verify(fixture.loggerBatchProcessor, never()).add(any())
+    assertClientReport(
+      fixture.sentryOptions.clientReportRecorder,
+      listOf(
+        DiscardedEvent(DiscardReason.EVENT_PROCESSOR.reason, DataCategory.LogItem.category, 1),
+        DiscardedEvent(
+          DiscardReason.EVENT_PROCESSOR.reason,
+          DataCategory.LogByte.category,
+          logEventNumberOfBytes,
+        ),
+      ),
+    )
+  }
+
   @Test
   fun `when beforeSendLog is returns new instance, new instance is sent`() {
     val scope = createScope()
@@ -418,6 +452,39 @@ class SentryClientTest {
     )
   }
 
+  @Test
+  fun `when metric is dropped by event processor, metric byte discard is recorded`() {
+    val scope = createScope()
+    val metricsEvent = SentryMetricsEvent(SentryId(), SentryNanotimeDate(), "name", "gauge", 123.0)
+    val metricsEventNumberOfBytes =
+      JsonSerializationUtils.byteSizeOf(
+        fixture.sentryOptions.serializer,
+        fixture.sentryOptions.logger,
+        metricsEvent,
+      )
+    scope.addEventProcessor(
+      object : EventProcessor {
+        override fun process(event: SentryMetricsEvent, hint: Hint): SentryMetricsEvent? = null
+      }
+    )
+
+    val sut = fixture.getSut()
+    sut.captureMetric(metricsEvent, scope, null)
+
+    verify(fixture.metricsBatchProcessor, never()).add(any())
+    assertClientReport(
+      fixture.sentryOptions.clientReportRecorder,
+      listOf(
+        DiscardedEvent(DiscardReason.EVENT_PROCESSOR.reason, DataCategory.TraceMetric.category, 1),
+        DiscardedEvent(
+          DiscardReason.EVENT_PROCESSOR.reason,
+          DataCategory.TraceMetricByte.category,
+          metricsEventNumberOfBytes,
+        ),
+      ),
+    )
+  }
+
   @Test
   fun `when beforeSendMetric is returns new instance, new instance is sent`() {
     val scope = createScope()