From bfe73e90d32b5bfceb2682fab644cb8e240a1641 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Tue, 12 Mar 2024 00:55:38 +0100
Subject: [PATCH 01/11] Introduced trace post-processing

---
 .../trace/agent/test/AgentTestRunner.groovy   |  6 +++
 .../trace/api/config/TracerConfig.java        |  4 ++
 .../trace/api/internal/TraceSegment.java      | 10 +++++
 .../common/writer/TraceProcessingWorker.java  | 43 +++++++++++++++++++
 .../datadog/trace/core/DDSpanContext.java     | 10 +++++
 .../postprocessor/AppSecPostProcessor.java    | 12 ++++++
 .../postprocessor/TracePostProcessor.java     |  9 ++++
 .../main/java/datadog/trace/api/Config.java   | 17 ++++++++
 .../trace/util/AgentThreadFactory.java        |  1 +
 9 files changed, 112 insertions(+)
 create mode 100644 dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
 create mode 100644 dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java

diff --git a/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy b/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
index b323128d638..f2b5963303f 100644
--- a/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
+++ b/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
@@ -551,6 +551,12 @@ abstract class AgentTestRunner extends DDSpecification implements AgentBuilder.L
       check()
       return delegate.getDataCurrent(key)
     }
+
+    @Override
+    void setRequiresPostProcessing(boolean postProcessing) {
+      check()
+      delegate.setRequiresPostProcessing(postProcessing)
+    }
   }
 
   /** Override to clean up things after the agent is removed */
diff --git a/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java b/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
index 3cf94286aa5..f82697d40cb 100644
--- a/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
+++ b/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
@@ -133,5 +133,9 @@ public final class TracerConfig {
 
   public static final String TRACE_FLUSH_INTERVAL = "trace.flush.interval";
 
+  public static final String TRACE_POST_PROCESSING_ENABLED = "trace.post-processing.enabled";
+
+  public static final String TRACE_POST_PROCESSING_TIMEOUT = "trace.post-processing.timeout";
+
   private TracerConfig() {}
 }
diff --git a/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java b/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
index cf1ce90fa15..6d3f6e6ef03 100644
--- a/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
+++ b/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
@@ -75,6 +75,13 @@ default void setTagCurrent(String key, Object value) {
    */
   void setDataCurrent(String key, Object value);
 
+  /**
+   * Set flag to indicate the need for post-processing
+   *
+   * @param postProcessing flag to indicate the need for post-processing
+   */
+  void setRequiresPostProcessing(boolean postProcessing);
+
   /**
    * Gets the value of the tag from the current span in this {@code TraceSegment}.
    *
@@ -112,5 +119,8 @@ public void setDataCurrent(String key, Object value) {}
     public Object getDataCurrent(String key) {
       return null;
     }
+
+    @Override
+    public void setRequiresPostProcessing(boolean postProcessing) {}
   }
 }
diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index 99d55fb2732..77c3c818246 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -13,7 +13,11 @@
 import datadog.trace.common.writer.ddagent.PrioritizationStrategy;
 import datadog.trace.core.CoreSpan;
 import datadog.trace.core.DDSpan;
+import datadog.trace.core.DDSpanContext;
 import datadog.trace.core.monitor.HealthMetrics;
+import datadog.trace.core.postprocessor.AppSecPostProcessor;
+import datadog.trace.core.postprocessor.TracePostProcessor;
+import datadog.trace.util.AgentThreadFactory;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -206,6 +210,7 @@ public abstract static class TraceSerializingHandler implements Runnable {
     private final boolean doTimeFlush;
     private final PayloadDispatcher payloadDispatcher;
     private long lastTicks;
+    private final TracePostProcessor tracePostProcessor;
 
     public TraceSerializingHandler(
         final MpscBlockingConsumerArrayQueue<Object> primaryQueue,
@@ -225,6 +230,7 @@ public TraceSerializingHandler(
       } else {
         this.ticksRequiredToFlush = Long.MAX_VALUE;
       }
+      this.tracePostProcessor = new AppSecPostProcessor();
     }
 
     @SuppressWarnings("unchecked")
@@ -235,6 +241,7 @@ public void onEvent(Object event) {
       try {
         if (event instanceof List) {
           List<DDSpan> trace = (List<DDSpan>) event;
+          maybeTracePostProcessing(trace);
           // TODO populate `_sample_rate` metric in a way that accounts for lost/dropped traces
           payloadDispatcher.addTrace(trace);
         } else if (event instanceof FlushEvent) {
@@ -295,5 +302,41 @@ private void consumeBatch(MessagePassingQueue<Object> queue) {
     protected boolean queuesAreEmpty() {
       return primaryQueue.isEmpty() && secondaryQueue.isEmpty();
     }
+
+    private void maybeTracePostProcessing(List<DDSpan> trace) {
+      if (!Config.get().isTracePostProcessingEnabled()) {
+        return;
+      }
+
+      if (trace == null || trace.isEmpty()) {
+        return;
+      }
+
+      DDSpanContext context = trace.get(0).context();
+      if (context == null || !context.isRequiresPostProcessing()) {
+        return;
+      }
+
+      Thread thread =
+          AgentThreadFactory.newAgentThread(
+              AgentThreadFactory.AgentThread.TRACE_POST_PROCESSOR,
+              () -> {
+                // do a trace post-processing work
+                tracePostProcessor.process(trace, context);
+              });
+      thread.start();
+
+      try {
+        long timeout = Config.get().getTracePostProcessingTimeout();
+        thread.join(timeout);
+        if (thread.isAlive()) {
+          thread.interrupt();
+        }
+      } catch (InterruptedException e) {
+        if (log.isDebugEnabled()) {
+          log.debug("Trace post-processing is interrupted.", e);
+        }
+      }
+    }
   }
 }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
index 0811a9807aa..a2cc0bc6d2e 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
@@ -140,6 +140,7 @@ public class DDSpanContext
   private final boolean injectBaggageAsTags;
   private volatile int encodedOperationName;
   private volatile int encodedResourceName;
+  private boolean requiresPostProcessing;
 
   public DDSpanContext(
       final DDTraceId traceId,
@@ -944,4 +945,13 @@ private String getTagName(String key) {
     // TODO is this decided?
     return "_dd." + key + ".json";
   }
+
+  @Override
+  public void setRequiresPostProcessing(boolean postProcessing) {
+    this.requiresPostProcessing = postProcessing;
+  }
+
+  public boolean isRequiresPostProcessing() {
+    return requiresPostProcessing;
+  }
 }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
new file mode 100644
index 00000000000..1c8bd10dc35
--- /dev/null
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
@@ -0,0 +1,12 @@
+package datadog.trace.core.postprocessor;
+
+import datadog.trace.core.DDSpan;
+import datadog.trace.core.DDSpanContext;
+import java.util.List;
+
+public class AppSecPostProcessor implements TracePostProcessor {
+  @Override
+  public void process(List<DDSpan> trace, DDSpanContext context) {
+    // Do AppSec post-processing
+  }
+}
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
new file mode 100644
index 00000000000..c8b678bdfa7
--- /dev/null
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
@@ -0,0 +1,9 @@
+package datadog.trace.core.postprocessor;
+
+import datadog.trace.core.DDSpan;
+import datadog.trace.core.DDSpanContext;
+import java.util.List;
+
+public interface TracePostProcessor {
+  void process(List<DDSpan> trace, DDSpanContext context);
+}
diff --git a/internal-api/src/main/java/datadog/trace/api/Config.java b/internal-api/src/main/java/datadog/trace/api/Config.java
index 519552a4718..21391e7618f 100644
--- a/internal-api/src/main/java/datadog/trace/api/Config.java
+++ b/internal-api/src/main/java/datadog/trace/api/Config.java
@@ -436,6 +436,8 @@
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_COMPONENT_OVERRIDES;
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_DEFAULTS_ENABLED;
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_MAPPING;
+import static datadog.trace.api.config.TracerConfig.TRACE_POST_PROCESSING_ENABLED;
+import static datadog.trace.api.config.TracerConfig.TRACE_POST_PROCESSING_TIMEOUT;
 import static datadog.trace.api.config.TracerConfig.TRACE_PROPAGATION_EXTRACT_FIRST;
 import static datadog.trace.api.config.TracerConfig.TRACE_PROPAGATION_STYLE;
 import static datadog.trace.api.config.TracerConfig.TRACE_PROPAGATION_STYLE_EXTRACT;
@@ -928,6 +930,8 @@ static class HostNameHolder {
 
   private final boolean axisPromoteResourceName;
   private final float traceFlushIntervalSeconds;
+  private final boolean tracePostProcessingEnabled;
+  private final long tracePostProcessingTimeout;
 
   private final boolean telemetryDebugRequestsEnabled;
 
@@ -2042,6 +2046,11 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
           "Agentless profiling activated but no api key provided. Profile uploading will likely fail");
     }
 
+    this.tracePostProcessingEnabled =
+        configProvider.getBoolean(TRACE_POST_PROCESSING_ENABLED, true);
+
+    this.tracePostProcessingTimeout = configProvider.getLong(TRACE_POST_PROCESSING_TIMEOUT, 1000);
+
     if (isCiVisibilityEnabled()
         && ciVisibilityAgentlessEnabled
         && (apiKey == null || apiKey.isEmpty())) {
@@ -2142,6 +2151,14 @@ public float getTraceFlushIntervalSeconds() {
     return traceFlushIntervalSeconds;
   }
 
+  public boolean isTracePostProcessingEnabled() {
+    return tracePostProcessingEnabled;
+  }
+
+  public long getTracePostProcessingTimeout() {
+    return tracePostProcessingTimeout;
+  }
+
   public boolean isIntegrationSynapseLegacyOperationName() {
     return integrationSynapseLegacyOperationName;
   }
diff --git a/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java b/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
index a860b35b833..46c1fc0f95d 100644
--- a/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
+++ b/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
@@ -16,6 +16,7 @@ public enum AgentThread {
     TRACE_STARTUP("dd-agent-startup-datadog-tracer"),
     TRACE_MONITOR("dd-trace-monitor"),
     TRACE_PROCESSOR("dd-trace-processor"),
+    TRACE_POST_PROCESSOR("dd-trace-post-processor"),
     SPAN_SAMPLING_PROCESSOR("dd-span-sampling-processor"),
     TRACE_CASSANDRA_ASYNC_SESSION("dd-cassandra-session-executor"),
 

From da1e19b224929c0bb263572a8329d020887188af Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov@datadoghq.com>
Date: Mon, 18 Mar 2024 17:42:54 +0100
Subject: [PATCH 02/11] setRequiresPostProcessing fully moved to DDSpanContext

---
 .../datadog/trace/agent/test/AgentTestRunner.groovy    |  6 ------
 .../java/datadog/trace/api/internal/TraceSegment.java  | 10 ----------
 .../main/java/datadog/trace/core/DDSpanContext.java    |  1 -
 3 files changed, 17 deletions(-)

diff --git a/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy b/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
index f2b5963303f..b323128d638 100644
--- a/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
+++ b/dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/AgentTestRunner.groovy
@@ -551,12 +551,6 @@ abstract class AgentTestRunner extends DDSpecification implements AgentBuilder.L
       check()
       return delegate.getDataCurrent(key)
     }
-
-    @Override
-    void setRequiresPostProcessing(boolean postProcessing) {
-      check()
-      delegate.setRequiresPostProcessing(postProcessing)
-    }
   }
 
   /** Override to clean up things after the agent is removed */
diff --git a/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java b/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
index 6d3f6e6ef03..cf1ce90fa15 100644
--- a/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
+++ b/dd-trace-api/src/main/java/datadog/trace/api/internal/TraceSegment.java
@@ -75,13 +75,6 @@ default void setTagCurrent(String key, Object value) {
    */
   void setDataCurrent(String key, Object value);
 
-  /**
-   * Set flag to indicate the need for post-processing
-   *
-   * @param postProcessing flag to indicate the need for post-processing
-   */
-  void setRequiresPostProcessing(boolean postProcessing);
-
   /**
    * Gets the value of the tag from the current span in this {@code TraceSegment}.
    *
@@ -119,8 +112,5 @@ public void setDataCurrent(String key, Object value) {}
     public Object getDataCurrent(String key) {
       return null;
     }
-
-    @Override
-    public void setRequiresPostProcessing(boolean postProcessing) {}
   }
 }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
index a2cc0bc6d2e..d2efca11e36 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
@@ -946,7 +946,6 @@ private String getTagName(String key) {
     return "_dd." + key + ".json";
   }
 
-  @Override
   public void setRequiresPostProcessing(boolean postProcessing) {
     this.requiresPostProcessing = postProcessing;
   }

From 8ac8c0e17ba0152c6f98bc7fe5ec10eb6662fbaa Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov@datadoghq.com>
Date: Mon, 18 Mar 2024 18:11:41 +0100
Subject: [PATCH 03/11] Removed Thread creation and added timeout boolean
 supplier

---
 .../common/writer/TraceProcessingWorker.java  | 27 ++++++-------------
 .../postprocessor/AppSecPostProcessor.java    |  4 ++-
 .../postprocessor/TracePostProcessor.java     |  3 ++-
 3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index 77c3c818246..fca7b6ca81d 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -17,10 +17,11 @@
 import datadog.trace.core.monitor.HealthMetrics;
 import datadog.trace.core.postprocessor.AppSecPostProcessor;
 import datadog.trace.core.postprocessor.TracePostProcessor;
-import datadog.trace.util.AgentThreadFactory;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
+import java.util.function.BooleanSupplier;
+
 import org.jctools.queues.MessagePassingQueue;
 import org.jctools.queues.MpscBlockingConsumerArrayQueue;
 import org.slf4j.Logger;
@@ -317,25 +318,13 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
         return;
       }
 
-      Thread thread =
-          AgentThreadFactory.newAgentThread(
-              AgentThreadFactory.AgentThread.TRACE_POST_PROCESSOR,
-              () -> {
-                // do a trace post-processing work
-                tracePostProcessor.process(trace, context);
-              });
-      thread.start();
+      long timeout = Config.get().getTracePostProcessingTimeout();
+      long deadline = System.currentTimeMillis() + timeout;
+      BooleanSupplier timeoutCheck =
+          () -> System.currentTimeMillis() > deadline;
 
-      try {
-        long timeout = Config.get().getTracePostProcessingTimeout();
-        thread.join(timeout);
-        if (thread.isAlive()) {
-          thread.interrupt();
-        }
-      } catch (InterruptedException e) {
-        if (log.isDebugEnabled()) {
-          log.debug("Trace post-processing is interrupted.", e);
-        }
+      if (!tracePostProcessor.process(trace, context, timeoutCheck)) {
+        log.debug("Trace post-processing is interrupted due to timeout.");
       }
     }
   }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
index 1c8bd10dc35..92ada522823 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
@@ -3,10 +3,12 @@
 import datadog.trace.core.DDSpan;
 import datadog.trace.core.DDSpanContext;
 import java.util.List;
+import java.util.function.BooleanSupplier;
 
 public class AppSecPostProcessor implements TracePostProcessor {
   @Override
-  public void process(List<DDSpan> trace, DDSpanContext context) {
+  public boolean process(List<DDSpan> trace, DDSpanContext context, BooleanSupplier timeoutCheck) {
     // Do AppSec post-processing
+    return true;
   }
 }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
index c8b678bdfa7..191ef2f5071 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
@@ -3,7 +3,8 @@
 import datadog.trace.core.DDSpan;
 import datadog.trace.core.DDSpanContext;
 import java.util.List;
+import java.util.function.BooleanSupplier;
 
 public interface TracePostProcessor {
-  void process(List<DDSpan> trace, DDSpanContext context);
+  boolean process(List<DDSpan> trace, DDSpanContext context, BooleanSupplier timeoutCheck);
 }

From d70d1cfef58f0cc9a143d92e702181c6051baaf9 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov@datadoghq.com>
Date: Mon, 18 Mar 2024 18:19:53 +0100
Subject: [PATCH 04/11] Removed option to disable post-processing

---
 .../main/java/datadog/trace/api/config/TracerConfig.java | 2 --
 .../trace/common/writer/TraceProcessingWorker.java       | 8 +-------
 internal-api/src/main/java/datadog/trace/api/Config.java | 9 ---------
 3 files changed, 1 insertion(+), 18 deletions(-)

diff --git a/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java b/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
index f82697d40cb..cb1e1c1baa1 100644
--- a/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
+++ b/dd-trace-api/src/main/java/datadog/trace/api/config/TracerConfig.java
@@ -133,8 +133,6 @@ public final class TracerConfig {
 
   public static final String TRACE_FLUSH_INTERVAL = "trace.flush.interval";
 
-  public static final String TRACE_POST_PROCESSING_ENABLED = "trace.post-processing.enabled";
-
   public static final String TRACE_POST_PROCESSING_TIMEOUT = "trace.post-processing.timeout";
 
   private TracerConfig() {}
diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index fca7b6ca81d..7827b89bb18 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -21,7 +21,6 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BooleanSupplier;
-
 import org.jctools.queues.MessagePassingQueue;
 import org.jctools.queues.MpscBlockingConsumerArrayQueue;
 import org.slf4j.Logger;
@@ -305,10 +304,6 @@ protected boolean queuesAreEmpty() {
     }
 
     private void maybeTracePostProcessing(List<DDSpan> trace) {
-      if (!Config.get().isTracePostProcessingEnabled()) {
-        return;
-      }
-
       if (trace == null || trace.isEmpty()) {
         return;
       }
@@ -320,8 +315,7 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
 
       long timeout = Config.get().getTracePostProcessingTimeout();
       long deadline = System.currentTimeMillis() + timeout;
-      BooleanSupplier timeoutCheck =
-          () -> System.currentTimeMillis() > deadline;
+      BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
 
       if (!tracePostProcessor.process(trace, context, timeoutCheck)) {
         log.debug("Trace post-processing is interrupted due to timeout.");
diff --git a/internal-api/src/main/java/datadog/trace/api/Config.java b/internal-api/src/main/java/datadog/trace/api/Config.java
index 21391e7618f..e95a11d9ca5 100644
--- a/internal-api/src/main/java/datadog/trace/api/Config.java
+++ b/internal-api/src/main/java/datadog/trace/api/Config.java
@@ -436,7 +436,6 @@
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_COMPONENT_OVERRIDES;
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_DEFAULTS_ENABLED;
 import static datadog.trace.api.config.TracerConfig.TRACE_PEER_SERVICE_MAPPING;
-import static datadog.trace.api.config.TracerConfig.TRACE_POST_PROCESSING_ENABLED;
 import static datadog.trace.api.config.TracerConfig.TRACE_POST_PROCESSING_TIMEOUT;
 import static datadog.trace.api.config.TracerConfig.TRACE_PROPAGATION_EXTRACT_FIRST;
 import static datadog.trace.api.config.TracerConfig.TRACE_PROPAGATION_STYLE;
@@ -930,7 +929,6 @@ static class HostNameHolder {
 
   private final boolean axisPromoteResourceName;
   private final float traceFlushIntervalSeconds;
-  private final boolean tracePostProcessingEnabled;
   private final long tracePostProcessingTimeout;
 
   private final boolean telemetryDebugRequestsEnabled;
@@ -2046,9 +2044,6 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
           "Agentless profiling activated but no api key provided. Profile uploading will likely fail");
     }
 
-    this.tracePostProcessingEnabled =
-        configProvider.getBoolean(TRACE_POST_PROCESSING_ENABLED, true);
-
     this.tracePostProcessingTimeout = configProvider.getLong(TRACE_POST_PROCESSING_TIMEOUT, 1000);
 
     if (isCiVisibilityEnabled()
@@ -2151,10 +2146,6 @@ public float getTraceFlushIntervalSeconds() {
     return traceFlushIntervalSeconds;
   }
 
-  public boolean isTracePostProcessingEnabled() {
-    return tracePostProcessingEnabled;
-  }
-
   public long getTracePostProcessingTimeout() {
     return tracePostProcessingTimeout;
   }

From 2dc3605c87c305cdca6ef78e25a672fafa355c4a Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Tue, 26 Mar 2024 10:03:47 +0100
Subject: [PATCH 05/11] TracePostProcessor replaced with SpanPostProcessor

---
 .../common/writer/TraceProcessingWorker.java  | 27 ++++++++++++-------
 .../postprocessor/AppSecPostProcessor.java    |  6 ++---
 ...tProcessor.java => SpanPostProcessor.java} |  5 ++--
 3 files changed, 22 insertions(+), 16 deletions(-)
 rename dd-trace-core/src/main/java/datadog/trace/core/postprocessor/{TracePostProcessor.java => SpanPostProcessor.java} (51%)

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index 7827b89bb18..b32788f7bbe 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -16,7 +16,7 @@
 import datadog.trace.core.DDSpanContext;
 import datadog.trace.core.monitor.HealthMetrics;
 import datadog.trace.core.postprocessor.AppSecPostProcessor;
-import datadog.trace.core.postprocessor.TracePostProcessor;
+import datadog.trace.core.postprocessor.SpanPostProcessor;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -210,7 +210,7 @@ public abstract static class TraceSerializingHandler implements Runnable {
     private final boolean doTimeFlush;
     private final PayloadDispatcher payloadDispatcher;
     private long lastTicks;
-    private final TracePostProcessor tracePostProcessor;
+    private final SpanPostProcessor spanPostProcessor;
 
     public TraceSerializingHandler(
         final MpscBlockingConsumerArrayQueue<Object> primaryQueue,
@@ -230,7 +230,7 @@ public TraceSerializingHandler(
       } else {
         this.ticksRequiredToFlush = Long.MAX_VALUE;
       }
-      this.tracePostProcessor = new AppSecPostProcessor();
+      this.spanPostProcessor = new AppSecPostProcessor();
     }
 
     @SuppressWarnings("unchecked")
@@ -308,17 +308,24 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
         return;
       }
 
-      DDSpanContext context = trace.get(0).context();
-      if (context == null || !context.isRequiresPostProcessing()) {
-        return;
-      }
-
       long timeout = Config.get().getTracePostProcessingTimeout();
       long deadline = System.currentTimeMillis() + timeout;
       BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
 
-      if (!tracePostProcessor.process(trace, context, timeoutCheck)) {
-        log.debug("Trace post-processing is interrupted due to timeout.");
+      for (DDSpan span : trace) {
+        if (timeoutCheck.getAsBoolean()) {
+          log.debug("Span post-processing is interrupted due to timeout.");
+          break;
+        }
+
+        DDSpanContext context = span.context();
+        if (context == null) {
+          continue;
+        }
+
+        if (context.isRequiresPostProcessing()) {
+          spanPostProcessor.process(span, context, timeoutCheck);
+        }
       }
     }
   }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
index 92ada522823..0af37f49931 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
@@ -2,12 +2,12 @@
 
 import datadog.trace.core.DDSpan;
 import datadog.trace.core.DDSpanContext;
-import java.util.List;
 import java.util.function.BooleanSupplier;
 
-public class AppSecPostProcessor implements TracePostProcessor {
+public class AppSecPostProcessor implements SpanPostProcessor {
+
   @Override
-  public boolean process(List<DDSpan> trace, DDSpanContext context, BooleanSupplier timeoutCheck) {
+  public boolean process(DDSpan span, DDSpanContext context, BooleanSupplier timeoutCheck) {
     // Do AppSec post-processing
     return true;
   }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
similarity index 51%
rename from dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
rename to dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
index 191ef2f5071..3e7a21bfbc5 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/TracePostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
@@ -2,9 +2,8 @@
 
 import datadog.trace.core.DDSpan;
 import datadog.trace.core.DDSpanContext;
-import java.util.List;
 import java.util.function.BooleanSupplier;
 
-public interface TracePostProcessor {
-  boolean process(List<DDSpan> trace, DDSpanContext context, BooleanSupplier timeoutCheck);
+public interface SpanPostProcessor {
+  boolean process(DDSpan trace, DDSpanContext context, BooleanSupplier timeoutCheck);
 }

From 81bd615351261c0ffb3cf058485b744b7038d764 Mon Sep 17 00:00:00 2001
From: ValentinZakharov <valentin.zakharov1@gmail.com>
Date: Wed, 27 Mar 2024 15:02:43 +0200
Subject: [PATCH 06/11] Update
 dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java

Co-authored-by: Stuart McCulloch <stuart.mcculloch@datadoghq.com>
---
 .../datadog/trace/core/postprocessor/SpanPostProcessor.java     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
index 3e7a21bfbc5..466ef3ab870 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
@@ -5,5 +5,5 @@
 import java.util.function.BooleanSupplier;
 
 public interface SpanPostProcessor {
-  boolean process(DDSpan trace, DDSpanContext context, BooleanSupplier timeoutCheck);
+  boolean process(DDSpan span, DDSpanContext context, BooleanSupplier timeoutCheck);
 }

From a7ccdef27b5a9bf8d842d5185f3b789ade0aa947 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Wed, 27 Mar 2024 16:06:07 +0100
Subject: [PATCH 07/11] Minor improvements for pr-review

---
 .../common/writer/TraceProcessingWorker.java  | 31 ++++++++++++-------
 .../datadog/trace/core/DDSpanContext.java     |  2 +-
 .../postprocessor/AppSecPostProcessor.java    |  3 +-
 .../core/postprocessor/SpanPostProcessor.java | 19 ++++++++++--
 .../trace/util/AgentThreadFactory.java        |  1 -
 5 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index b32788f7bbe..e67a49b8f9e 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -17,6 +17,8 @@
 import datadog.trace.core.monitor.HealthMetrics;
 import datadog.trace.core.postprocessor.AppSecPostProcessor;
 import datadog.trace.core.postprocessor.SpanPostProcessor;
+
+import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -308,24 +310,31 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
         return;
       }
 
+      // Filter spans that need post-processing
+      List<DDSpan> spansToPostProcess = null;
+      for (DDSpan span : trace) {
+        DDSpanContext context = span.context();
+        if (context != null && context.isRequiresPostProcessing()) {
+          if (spansToPostProcess == null) {
+            spansToPostProcess = new ArrayList<>();
+          }
+          spansToPostProcess.add(span);
+        }
+      }
+
+      if (spansToPostProcess == null) {
+        return;
+      }
+
       long timeout = Config.get().getTracePostProcessingTimeout();
       long deadline = System.currentTimeMillis() + timeout;
       BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
 
-      for (DDSpan span : trace) {
-        if (timeoutCheck.getAsBoolean()) {
+      for (DDSpan span : spansToPostProcess) {
+        if (timeoutCheck.getAsBoolean() || !spanPostProcessor.process(span, timeoutCheck)) {
           log.debug("Span post-processing is interrupted due to timeout.");
           break;
         }
-
-        DDSpanContext context = span.context();
-        if (context == null) {
-          continue;
-        }
-
-        if (context.isRequiresPostProcessing()) {
-          spanPostProcessor.process(span, context, timeoutCheck);
-        }
       }
     }
   }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
index d2efca11e36..eb11bb93b40 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
@@ -140,7 +140,7 @@ public class DDSpanContext
   private final boolean injectBaggageAsTags;
   private volatile int encodedOperationName;
   private volatile int encodedResourceName;
-  private boolean requiresPostProcessing;
+  private volatile boolean requiresPostProcessing;
 
   public DDSpanContext(
       final DDTraceId traceId,
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
index 0af37f49931..4897d183a19 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
@@ -1,13 +1,12 @@
 package datadog.trace.core.postprocessor;
 
 import datadog.trace.core.DDSpan;
-import datadog.trace.core.DDSpanContext;
 import java.util.function.BooleanSupplier;
 
 public class AppSecPostProcessor implements SpanPostProcessor {
 
   @Override
-  public boolean process(DDSpan span, DDSpanContext context, BooleanSupplier timeoutCheck) {
+  public boolean process(DDSpan span, BooleanSupplier timeoutCheck) {
     // Do AppSec post-processing
     return true;
   }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
index 466ef3ab870..14708410534 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
@@ -1,9 +1,24 @@
 package datadog.trace.core.postprocessor;
 
 import datadog.trace.core.DDSpan;
-import datadog.trace.core.DDSpanContext;
 import java.util.function.BooleanSupplier;
 
+/**
+ * Span Post-processing with a timeout check capability.
+ * <p>
+ * Implementations of this interface should carry out post-processing of spans while supporting
+ * interruption when a specified time limit is exceeded. The method {@code process}
+ * must check the state of {@code timeoutCheck} while processing span. If {@code timeoutCheck.getAsBoolean()}
+ * returns {@code true}, processing should be immediately halted, and the method should return {@code false}.
+ * If post-processing completes successfully before the timeout, the method should return {@code true}.
+ */
 public interface SpanPostProcessor {
-  boolean process(DDSpan span, DDSpanContext context, BooleanSupplier timeoutCheck);
+  /**
+   * Post-processes a span.
+   * <p>
+   * @param span The span to be post-processed.
+   * @param timeoutCheck A timeout check returning {@code true} if the allotted time has elapsed.
+   * @return {@code true} if the span was successfully processed; {@code false} in case of a timeout.
+   */
+  boolean process(DDSpan span, BooleanSupplier timeoutCheck);
 }
diff --git a/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java b/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
index 46c1fc0f95d..a860b35b833 100644
--- a/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
+++ b/internal-api/src/main/java/datadog/trace/util/AgentThreadFactory.java
@@ -16,7 +16,6 @@ public enum AgentThread {
     TRACE_STARTUP("dd-agent-startup-datadog-tracer"),
     TRACE_MONITOR("dd-trace-monitor"),
     TRACE_PROCESSOR("dd-trace-processor"),
-    TRACE_POST_PROCESSOR("dd-trace-post-processor"),
     SPAN_SAMPLING_PROCESSOR("dd-span-sampling-processor"),
     TRACE_CASSANDRA_ASYNC_SESSION("dd-cassandra-session-executor"),
 

From ed04cb27a51224b33269eef1a6a1d09b9e895655 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Wed, 27 Mar 2024 16:18:05 +0100
Subject: [PATCH 08/11] Spotless

---
 .../common/writer/TraceProcessingWorker.java   |  1 -
 .../core/postprocessor/SpanPostProcessor.java  | 18 ++++++++++--------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index e67a49b8f9e..dfc5e5c8d45 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -17,7 +17,6 @@
 import datadog.trace.core.monitor.HealthMetrics;
 import datadog.trace.core.postprocessor.AppSecPostProcessor;
 import datadog.trace.core.postprocessor.SpanPostProcessor;
-
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
index 14708410534..8751959456f 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/SpanPostProcessor.java
@@ -5,20 +5,22 @@
 
 /**
  * Span Post-processing with a timeout check capability.
- * <p>
- * Implementations of this interface should carry out post-processing of spans while supporting
- * interruption when a specified time limit is exceeded. The method {@code process}
- * must check the state of {@code timeoutCheck} while processing span. If {@code timeoutCheck.getAsBoolean()}
- * returns {@code true}, processing should be immediately halted, and the method should return {@code false}.
- * If post-processing completes successfully before the timeout, the method should return {@code true}.
+ *
+ * <p>Implementations of this interface should carry out post-processing of spans while supporting
+ * interruption when a specified time limit is exceeded. The method {@code process} must check the
+ * state of {@code timeoutCheck} while processing span. If {@code timeoutCheck.getAsBoolean()}
+ * returns {@code true}, processing should be immediately halted, and the method should return
+ * {@code false}. If post-processing completes successfully before the timeout, the method should
+ * return {@code true}.
  */
 public interface SpanPostProcessor {
   /**
    * Post-processes a span.
-   * <p>
+   *
    * @param span The span to be post-processed.
    * @param timeoutCheck A timeout check returning {@code true} if the allotted time has elapsed.
-   * @return {@code true} if the span was successfully processed; {@code false} in case of a timeout.
+   * @return {@code true} if the span was successfully processed; {@code false} in case of a
+   *     timeout.
    */
   boolean process(DDSpan span, BooleanSupplier timeoutCheck);
 }

From 96342fffa911d31e4168260cc8c7997f8ee35416 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Wed, 27 Mar 2024 22:47:04 +0100
Subject: [PATCH 09/11] Default trace post-processing timeout value

---
 .../src/main/java/datadog/trace/api/ConfigDefaults.java       | 2 ++
 internal-api/src/main/java/datadog/trace/api/Config.java      | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java b/dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java
index 02f41c3a9ab..2988e995164 100644
--- a/dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java
+++ b/dd-trace-api/src/main/java/datadog/trace/api/ConfigDefaults.java
@@ -215,6 +215,8 @@ public final class ConfigDefaults {
 
   static final float DEFAULT_TRACE_FLUSH_INTERVAL = 1;
 
+  static final long DEFAULT_TRACE_POST_PROCESSING_TIMEOUT = 1000; // 1 second
+
   static final boolean DEFAULT_COUCHBASE_INTERNAL_SPANS_ENABLED = true;
   static final boolean DEFAULT_ELASTICSEARCH_BODY_ENABLED = false;
   static final boolean DEFAULT_ELASTICSEARCH_PARAMS_ENABLED = true;
diff --git a/internal-api/src/main/java/datadog/trace/api/Config.java b/internal-api/src/main/java/datadog/trace/api/Config.java
index e95a11d9ca5..ee0f152782d 100644
--- a/internal-api/src/main/java/datadog/trace/api/Config.java
+++ b/internal-api/src/main/java/datadog/trace/api/Config.java
@@ -2044,7 +2044,9 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
           "Agentless profiling activated but no api key provided. Profile uploading will likely fail");
     }
 
-    this.tracePostProcessingTimeout = configProvider.getLong(TRACE_POST_PROCESSING_TIMEOUT, 1000);
+    this.tracePostProcessingTimeout =
+        configProvider.getLong(
+            TRACE_POST_PROCESSING_TIMEOUT, ConfigDefaults.DEFAULT_TRACE_POST_PROCESSING_TIMEOUT);
 
     if (isCiVisibilityEnabled()
         && ciVisibilityAgentlessEnabled

From 749f577418e9f8d3a75ab186230a4b56e3a3675e Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Fri, 12 Apr 2024 12:55:26 +0200
Subject: [PATCH 10/11] Added test

---
 .../trace/common/writer/DDAgentWriter.java    |  3 +-
 .../trace/common/writer/DDIntakeWriter.java   |  3 +-
 .../common/writer/TraceProcessingWorker.java  | 51 ++++++++++----
 .../postprocessor/AppSecPostProcessor.java    | 13 ----
 .../writer/TraceProcessingWorkerTest.groovy   | 69 +++++++++++++++++--
 5 files changed, 106 insertions(+), 33 deletions(-)
 delete mode 100644 dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/DDAgentWriter.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/DDAgentWriter.java
index a29b07a4af9..0c85cb49abc 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/DDAgentWriter.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/DDAgentWriter.java
@@ -154,7 +154,8 @@ public DDAgentWriter build() {
               null == prioritization ? FAST_LANE : prioritization,
               flushIntervalMilliseconds,
               TimeUnit.MILLISECONDS,
-              singleSpanSampler);
+              singleSpanSampler,
+              null);
 
       return new DDAgentWriter(traceProcessingWorker, dispatcher, healthMetrics, alwaysFlush);
     }
diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/DDIntakeWriter.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/DDIntakeWriter.java
index d5e70dd6b47..7075266352c 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/DDIntakeWriter.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/DDIntakeWriter.java
@@ -122,7 +122,8 @@ public DDIntakeWriter build() {
               prioritization,
               flushIntervalMilliseconds,
               TimeUnit.MILLISECONDS,
-              singleSpanSampler);
+              singleSpanSampler,
+              null);
 
       return new DDIntakeWriter(
           traceProcessingWorker,
diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index dfc5e5c8d45..a5ec8961caa 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -15,7 +15,6 @@
 import datadog.trace.core.DDSpan;
 import datadog.trace.core.DDSpanContext;
 import datadog.trace.core.monitor.HealthMetrics;
-import datadog.trace.core.postprocessor.AppSecPostProcessor;
 import datadog.trace.core.postprocessor.SpanPostProcessor;
 import java.util.ArrayList;
 import java.util.List;
@@ -55,7 +54,8 @@ public TraceProcessingWorker(
       final Prioritization prioritization,
       final long flushInterval,
       final TimeUnit timeUnit,
-      final SingleSpanSampler singleSpanSampler) {
+      final SingleSpanSampler singleSpanSampler,
+      final SpanPostProcessor spanPostProcessor) {
     this.capacity = capacity;
     this.primaryQueue = createQueue(capacity);
     this.secondaryQueue = createQueue(capacity);
@@ -78,9 +78,21 @@ public TraceProcessingWorker(
     this.serializingHandler =
         runAsDaemon
             ? new DaemonTraceSerializingHandler(
-                primaryQueue, secondaryQueue, healthMetrics, dispatcher, flushInterval, timeUnit)
+                primaryQueue,
+                secondaryQueue,
+                healthMetrics,
+                dispatcher,
+                flushInterval,
+                timeUnit,
+                spanPostProcessor)
             : new NonDaemonTraceSerializingHandler(
-                primaryQueue, secondaryQueue, healthMetrics, dispatcher, flushInterval, timeUnit);
+                primaryQueue,
+                secondaryQueue,
+                healthMetrics,
+                dispatcher,
+                flushInterval,
+                timeUnit,
+                spanPostProcessor);
     this.serializerThread = newAgentThread(TRACE_PROCESSOR, serializingHandler, runAsDaemon);
   }
 
@@ -139,9 +151,16 @@ public DaemonTraceSerializingHandler(
         HealthMetrics healthMetrics,
         PayloadDispatcher payloadDispatcher,
         long flushInterval,
-        TimeUnit timeUnit) {
+        TimeUnit timeUnit,
+        SpanPostProcessor spanPostProcessor) {
       super(
-          primaryQueue, secondaryQueue, healthMetrics, payloadDispatcher, flushInterval, timeUnit);
+          primaryQueue,
+          secondaryQueue,
+          healthMetrics,
+          payloadDispatcher,
+          flushInterval,
+          timeUnit,
+          spanPostProcessor);
     }
 
     @Override
@@ -174,9 +193,16 @@ public NonDaemonTraceSerializingHandler(
         HealthMetrics healthMetrics,
         PayloadDispatcher payloadDispatcher,
         long flushInterval,
-        TimeUnit timeUnit) {
+        TimeUnit timeUnit,
+        SpanPostProcessor spanPostProcessor) {
       super(
-          primaryQueue, secondaryQueue, healthMetrics, payloadDispatcher, flushInterval, timeUnit);
+          primaryQueue,
+          secondaryQueue,
+          healthMetrics,
+          payloadDispatcher,
+          flushInterval,
+          timeUnit,
+          spanPostProcessor);
     }
 
     @Override
@@ -219,7 +245,8 @@ public TraceSerializingHandler(
         final HealthMetrics healthMetrics,
         final PayloadDispatcher payloadDispatcher,
         final long flushInterval,
-        final TimeUnit timeUnit) {
+        final TimeUnit timeUnit,
+        final SpanPostProcessor spanPostProcessor) {
       this.primaryQueue = primaryQueue;
       this.secondaryQueue = secondaryQueue;
       this.healthMetrics = healthMetrics;
@@ -231,7 +258,7 @@ public TraceSerializingHandler(
       } else {
         this.ticksRequiredToFlush = Long.MAX_VALUE;
       }
-      this.spanPostProcessor = new AppSecPostProcessor();
+      this.spanPostProcessor = spanPostProcessor;
     }
 
     @SuppressWarnings("unchecked")
@@ -330,8 +357,8 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
       BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
 
       for (DDSpan span : spansToPostProcess) {
-        if (timeoutCheck.getAsBoolean() || !spanPostProcessor.process(span, timeoutCheck)) {
-          log.debug("Span post-processing is interrupted due to timeout.");
+        if (!spanPostProcessor.process(span, timeoutCheck)) {
+          log.debug("Span post-processing interrupted due to timeout.");
           break;
         }
       }
diff --git a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java b/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
deleted file mode 100644
index 4897d183a19..00000000000
--- a/dd-trace-core/src/main/java/datadog/trace/core/postprocessor/AppSecPostProcessor.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package datadog.trace.core.postprocessor;
-
-import datadog.trace.core.DDSpan;
-import java.util.function.BooleanSupplier;
-
-public class AppSecPostProcessor implements SpanPostProcessor {
-
-  @Override
-  public boolean process(DDSpan span, BooleanSupplier timeoutCheck) {
-    // Do AppSec post-processing
-    return true;
-  }
-}
diff --git a/dd-trace-core/src/test/groovy/datadog/trace/common/writer/TraceProcessingWorkerTest.groovy b/dd-trace-core/src/test/groovy/datadog/trace/common/writer/TraceProcessingWorkerTest.groovy
index dd823a587be..b976dcdbe1e 100644
--- a/dd-trace-core/src/test/groovy/datadog/trace/common/writer/TraceProcessingWorkerTest.groovy
+++ b/dd-trace-core/src/test/groovy/datadog/trace/common/writer/TraceProcessingWorkerTest.groovy
@@ -4,7 +4,10 @@ import datadog.trace.common.sampling.SingleSpanSampler
 import datadog.trace.common.writer.ddagent.PrioritizationStrategy.PublishResult
 import datadog.trace.core.CoreSpan
 import datadog.trace.core.DDSpan
+import datadog.trace.core.DDSpanContext
+import datadog.trace.core.PendingTrace
 import datadog.trace.core.monitor.HealthMetrics
+import datadog.trace.core.postprocessor.SpanPostProcessor
 import datadog.trace.test.util.DDSpecification
 import spock.util.concurrent.PollingConditions
 
@@ -41,6 +44,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
       FAST_LANE,
       1,
       TimeUnit.NANOSECONDS,
+      null,
       null
       ) // stop heartbeats from being throttled
 
@@ -67,6 +71,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
       FAST_LANE,
       1,
       TimeUnit.NANOSECONDS,
+      null,
       null
       ) // stop heartbeats from being throttled
     def timeConditions = new PollingConditions(timeout: 1, initialDelay: 1, factor: 1.25)
@@ -92,7 +97,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
         false
       },
       FAST_LANE,
-      100, TimeUnit.SECONDS, null) // prevent heartbeats from helping the flush happen
+      100, TimeUnit.SECONDS, null, null) // prevent heartbeats from helping the flush happen
 
     when: "there is pending work it is completed before a flush"
     // processing this span will throw an exception, but it should be caught
@@ -131,7 +136,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
       throwingDispatcher, {
         false
       }, FAST_LANE,
-      100, TimeUnit.SECONDS, null) // prevent heartbeats from helping the flush happen
+      100, TimeUnit.SECONDS, null, null) // prevent heartbeats from helping the flush happen
     worker.start()
 
     when: "a trace is processed but can't be passed on"
@@ -149,6 +154,58 @@ class TraceProcessingWorkerTest extends DDSpecification {
     priority << [SAMPLER_DROP, USER_DROP, SAMPLER_KEEP, USER_KEEP, UNSET]
   }
 
+  def "trace should be post-processed"() {
+    setup:
+    AtomicInteger acceptedCount = new AtomicInteger()
+    PayloadDispatcherImpl countingDispatcher = Mock(PayloadDispatcherImpl)
+    countingDispatcher.addTrace(_) >> {
+      acceptedCount.getAndIncrement()
+    }
+    HealthMetrics healthMetrics = Mock(HealthMetrics)
+
+    // Span 1 - should be post-processed
+    def span1 = DDSpan.create("test", 0, Mock(DDSpanContext) {
+      isRequiresPostProcessing() >> true
+      getTrace() >> Mock(PendingTrace) {
+        getCurrentTimeNano() >> 0
+      }
+    }, [])
+    def processedSpan1 = false
+
+    // Span 2 - should NOT be post-processed
+    def span2 = DDSpan.create("test", 0, Mock(DDSpanContext) {
+      isRequiresPostProcessing() >> false
+      getTrace() >> Mock(PendingTrace) {
+        getCurrentTimeNano() >> 0
+      }
+    }, [])
+    def processedSpan2 = false
+
+    SpanPostProcessor spanPostProcessor = Mock(SpanPostProcessor) {
+      process(span1, _) >> { processedSpan1 = true }
+      process(span2, _) >> { processedSpan2 = true }
+    }
+
+    TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics,
+      countingDispatcher, {
+        false
+      }, FAST_LANE, 100, TimeUnit.SECONDS, null, spanPostProcessor)
+    worker.start()
+
+    when: "traces are submitted"
+    worker.publish(span1, SAMPLER_KEEP, [span1, span2])
+    worker.publish(span2, SAMPLER_KEEP, [span1, span2])
+
+    then: "traces are passed through unless rejected on submission"
+    conditions.eventually {
+      assert processedSpan1 == true
+      assert processedSpan2 == false
+    }
+
+    cleanup:
+    worker.close()
+  }
+
   def "traces should be processed"() {
     setup:
     AtomicInteger acceptedCount = new AtomicInteger()
@@ -160,7 +217,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
     TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics,
       countingDispatcher, {
         false
-      }, FAST_LANE, 100, TimeUnit.SECONDS, null)
+      }, FAST_LANE, 100, TimeUnit.SECONDS, null, null)
     // prevent heartbeats from helping the flush happen
     worker.start()
 
@@ -211,7 +268,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
     TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics,
       countingDispatcher, {
         false
-      }, FAST_LANE, 100, TimeUnit.SECONDS, null)
+      }, FAST_LANE, 100, TimeUnit.SECONDS, null, null)
     worker.start()
     worker.close()
     int queueSize = 0
@@ -248,7 +305,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
           return false
         }
       }
-    TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics, countingDispatcher, { true }, FAST_LANE, 100, TimeUnit.SECONDS, singleSpanSampler)
+    TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics, countingDispatcher, { true }, FAST_LANE, 100, TimeUnit.SECONDS, singleSpanSampler, null)
     worker.start()
 
     when: "traces are submitted"
@@ -324,7 +381,7 @@ class TraceProcessingWorkerTest extends DDSpecification {
           return false
         }
       }
-    TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics, countingDispatcher, { false }, FAST_LANE, 100, TimeUnit.SECONDS, singleSpanSampler)
+    TraceProcessingWorker worker = new TraceProcessingWorker(10, healthMetrics, countingDispatcher, { false }, FAST_LANE, 100, TimeUnit.SECONDS, singleSpanSampler, null)
     worker.start()
 
     when: "traces are submitted"

From ae1ecea607456595a57b8ead0c88d0a410fcf725 Mon Sep 17 00:00:00 2001
From: Valentin Zakharov <valentin.zakharov1@gmail.com>
Date: Tue, 16 Apr 2024 21:07:45 +0200
Subject: [PATCH 11/11] Catch any exception, if happens during span
 post-processing

---
 .../common/writer/TraceProcessingWorker.java  | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
index a5ec8961caa..c17c00932bb 100644
--- a/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
+++ b/dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java
@@ -352,14 +352,20 @@ private void maybeTracePostProcessing(List<DDSpan> trace) {
         return;
       }
 
-      long timeout = Config.get().getTracePostProcessingTimeout();
-      long deadline = System.currentTimeMillis() + timeout;
-      BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
-
-      for (DDSpan span : spansToPostProcess) {
-        if (!spanPostProcessor.process(span, timeoutCheck)) {
-          log.debug("Span post-processing interrupted due to timeout.");
-          break;
+      try {
+        long timeout = Config.get().getTracePostProcessingTimeout();
+        long deadline = System.currentTimeMillis() + timeout;
+        BooleanSupplier timeoutCheck = () -> System.currentTimeMillis() > deadline;
+
+        for (DDSpan span : spansToPostProcess) {
+          if (!spanPostProcessor.process(span, timeoutCheck)) {
+            log.debug("Span post-processing interrupted due to timeout.");
+            break;
+          }
+        }
+      } catch (Throwable e) {
+        if (log.isDebugEnabled()) {
+          log.debug("Error while trace post-processing", e);
         }
       }
     }