WIP: not yet ready for review (deprecate agent scope continuation)

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/Agent.java

@@ -26,6 +26,7 @@
 import datadog.instrument.utils.ClassLoaderValue;
 import datadog.metrics.api.statsd.StatsDClientManager;
 import datadog.trace.api.Config;
+import datadog.trace.api.InstrumenterConfig;
 import datadog.trace.api.Platform;
 import datadog.trace.api.WithGlobalTracer;
 import datadog.trace.api.appsec.AppSecEventTracker;
@@ -337,6 +338,10 @@ public static void start(
       StaticEventLogger.end("crashtracking");
     }
 
+    if (InstrumenterConfig.get().isLegacyContextManagerEnabled()) {
+      AgentTracer.installLegacyContextManager();
+    }
+
     startDatadogAgent(initTelemetry, inst);
 
     final EnumSet<Library> libraries = detectLibraries(log);

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/AdviceUtils.java

@@ -3,8 +3,9 @@
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.activeSpan;
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.isAsyncPropagationEnabled;
 
+import datadog.context.ContextContinuation;
+import datadog.context.ContextScope;
 import datadog.trace.bootstrap.ContextStore;
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 
 /** Helper utils for Runnable/Callable instrumentation */
@@ -18,16 +19,16 @@ public class AdviceUtils {
    * @param <T> task's type
    * @return scope if scope was started, or null
    */
-  public static <T> AgentScope startTaskScope(
+  public static <T> ContextScope startTaskScope(
       final ContextStore<T, State> contextStore, final T task) {
     return startTaskScope(contextStore.get(task));
   }
 
-  public static AgentScope startTaskScope(State state) {
+  public static ContextScope startTaskScope(State state) {
     if (state != null) {
-      final AgentScope.Continuation continuation = state.getAndResetContinuation();
+      final ContextContinuation continuation = state.getAndResetContinuation();
       if (continuation != null) {
-        final AgentScope scope = continuation.activate();
+        final ContextScope scope = continuation.resume();
         // important - stop timing after the scope has been activated so the time in the queue can
         // be attributed to the correct context without duplicating the propagated information
         state.stopTiming();
@@ -37,7 +38,7 @@ public static AgentScope startTaskScope(State state) {
     return null;
   }
 
-  public static void endTaskScope(final AgentScope scope) {
+  public static void endTaskScope(final ContextScope scope) {
     if (null != scope) {
       scope.close();
     }

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/ComparableRunnable.java

@@ -1,11 +1,11 @@
 package datadog.trace.bootstrap.instrumentation.java.concurrent;
 
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
+import datadog.context.ContextContinuation;
 
 public final class ComparableRunnable<T extends Runnable & Comparable<T>> extends Wrapper<T>
     implements Comparable<ComparableRunnable<T>> {
 
-  public ComparableRunnable(T delegate, AgentScope.Continuation continuation) {
+  public ComparableRunnable(T delegate, ContextContinuation continuation) {
     super(delegate, continuation);
   }
 

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/ConcurrentState.java

@@ -4,8 +4,9 @@
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.isAsyncPropagationEnabled;
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ContinuationClaim.CLAIMED;
 
+import datadog.context.ContextContinuation;
+import datadog.context.ContextScope;
 import datadog.trace.bootstrap.ContextStore;
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 import org.slf4j.Logger;
@@ -22,12 +23,12 @@ public final class ConcurrentState {
 
   public static ContextStore.Factory<ConcurrentState> FACTORY = ConcurrentState::new;
 
-  private volatile AgentScope.Continuation continuation = null;
+  private volatile ContextContinuation continuation = null;
 
-  private static final AtomicReferenceFieldUpdater<ConcurrentState, AgentScope.Continuation>
+  private static final AtomicReferenceFieldUpdater<ConcurrentState, ContextContinuation>
       CONTINUATION =
           AtomicReferenceFieldUpdater.newUpdater(
-              ConcurrentState.class, AgentScope.Continuation.class, "continuation");
+              ConcurrentState.class, ContextContinuation.class, "continuation");
 
   private ConcurrentState() {}
 
@@ -44,7 +45,7 @@ public static <K> ConcurrentState captureContinuation(
     return state;
   }
 
-  public static <K> AgentScope activateAndContinueContinuation(
+  public static <K> ContextScope activateAndContinueContinuation(
       ContextStore<K, ConcurrentState> contextStore, K key) {
     final ConcurrentState state = contextStore.get(key);
     if (state == null) {
@@ -54,7 +55,10 @@ public static <K> AgentScope activateAndContinueContinuation(
   }
 
   public static <K> void closeScope(
-      ContextStore<K, ConcurrentState> contextStore, K key, AgentScope scope, Throwable throwable) {
+      ContextStore<K, ConcurrentState> contextStore,
+      K key,
+      ContextScope scope,
+      Throwable throwable) {
     final ConcurrentState state = contextStore.get(key);
     if (scope != null) {
       scope.close();
@@ -88,27 +92,27 @@ private boolean captureAndSetContinuation(final AgentSpan span) {
     return false;
   }
 
-  private AgentScope activateAndContinueContinuation() {
-    final AgentScope.Continuation continuation = CONTINUATION.get(this);
+  private ContextScope activateAndContinueContinuation() {
+    final ContextContinuation continuation = CONTINUATION.get(this);
     if (continuation != null && continuation != CLAIMED) {
-      return continuation.activate();
+      return continuation.resume();
     }
     return null;
   }
 
   private void cancelContinuation() {
-    final AgentScope.Continuation continuation = CONTINUATION.get(this);
+    final ContextContinuation continuation = CONTINUATION.get(this);
     if (continuation != null && continuation != CLAIMED) {
-      continuation.cancel();
+      continuation.release();
     }
   }
 
   private void cancelAndClearContinuation() {
-    final AgentScope.Continuation continuation = CONTINUATION.get(this);
+    final ContextContinuation continuation = CONTINUATION.get(this);
     if (continuation != null && continuation != CLAIMED) {
       // We should never be able to reuse this state
       CONTINUATION.compareAndSet(this, continuation, CLAIMED);
-      continuation.cancel();
+      continuation.release();
     }
   }
 }

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/ContinuationClaim.java

@@ -1,29 +1,30 @@
 package datadog.trace.bootstrap.instrumentation.java.concurrent;
 
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
-import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
+import datadog.context.Context;
+import datadog.context.ContextContinuation;
+import datadog.context.ContextScope;
 
-final class ContinuationClaim implements AgentScope.Continuation {
+final class ContinuationClaim implements ContextContinuation {
 
   public static final ContinuationClaim CLAIMED = new ContinuationClaim();
 
   @Override
-  public AgentScope.Continuation hold() {
+  public ContextContinuation hold() {
     throw new IllegalStateException();
   }
 
   @Override
-  public AgentScope activate() {
+  public ContextScope resume() {
     throw new IllegalStateException();
   }
 
   @Override
-  public AgentSpan span() {
+  public Context context() {
     throw new IllegalStateException();
   }
 
   @Override
-  public void cancel() {
+  public void release() {
     throw new IllegalStateException();
   }
 }

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/State.java

@@ -3,21 +3,21 @@
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.captureSpan;
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ContinuationClaim.CLAIMED;
 
+import datadog.context.ContextContinuation;
 import datadog.trace.api.profiling.Timing;
 import datadog.trace.bootstrap.ContextStore;
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
 
 public final class State {
 
   public static ContextStore.Factory<State> FACTORY = State::new;
 
-  private static final AtomicReferenceFieldUpdater<State, AgentScope.Continuation> CONTINUATION =
+  private static final AtomicReferenceFieldUpdater<State, ContextContinuation> CONTINUATION =
       AtomicReferenceFieldUpdater.newUpdater(
-          State.class, AgentScope.Continuation.class, "continuation");
+          State.class, ContextContinuation.class, "continuation");
 
-  private volatile AgentScope.Continuation continuation = null;
+  private volatile ContextContinuation continuation = null;
 
   private static final AtomicReferenceFieldUpdater<State, Timing> TIMING =
       AtomicReferenceFieldUpdater.newUpdater(State.class, Timing.class, "timing");
@@ -40,34 +40,34 @@ public boolean captureAndSetContinuation(final AgentSpan span) {
     return false;
   }
 
-  public boolean setOrCancelContinuation(final AgentScope.Continuation continuation) {
+  public boolean setOrCancelContinuation(final ContextContinuation continuation) {
     if (CONTINUATION.compareAndSet(this, null, CLAIMED)) {
       // lazy write is guaranteed to be seen by getAndSet
       CONTINUATION.lazySet(this, continuation);
       return true;
     } else {
-      continuation.cancel();
+      continuation.release();
       return false;
     }
   }
 
   public void closeContinuation() {
-    AgentScope.Continuation continuation = getAndResetContinuation();
+    ContextContinuation continuation = getAndResetContinuation();
     if (null != continuation) {
-      continuation.cancel();
+      continuation.release();
     }
   }
 
   public AgentSpan getSpan() {
-    AgentScope.Continuation continuation = CONTINUATION.get(this);
-    if (null != continuation) {
-      return continuation.span();
+    ContextContinuation continuation = CONTINUATION.get(this);
+    if (null == continuation || CLAIMED == continuation) {
+      return null;
     }
-    return null;
+    return AgentSpan.fromContext(continuation.context());
   }
 
-  public AgentScope.Continuation getAndResetContinuation() {
-    AgentScope.Continuation continuation = CONTINUATION.get(this);
+  public ContextContinuation getAndResetContinuation() {
+    ContextContinuation continuation = CONTINUATION.get(this);
     if (null == continuation || CLAIMED == continuation) {
       return null;
     }

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/TPEHelper.java

@@ -3,18 +3,18 @@
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ExcludeFilter.ExcludeType.RUNNABLE;
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ExcludeFilter.exclude;
 
+import datadog.context.ContextScope;
 import datadog.trace.api.GenericClassValue;
 import datadog.trace.api.InstrumenterConfig;
 import datadog.trace.bootstrap.ContextStore;
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import java.util.Set;
 import java.util.concurrent.ThreadPoolExecutor;
 
 /**
  * This class is a helper for the ThreadPoolExecutorInstrumentation. The instrumentation has two
  * modes, where the legacy mode uses wrapping of the Runnable and the new mode uses the State
  * context store field in the actual Runnable. The ThreadLocal below is needed to transport the
- * AgentScope between two methods when using the context store approach. More details can be found
+ * ContextScope between two methods when using the context store approach. More details can be found
  * in the ThreadPoolExecutorInstrumentation.
  */
 public final class TPEHelper {
@@ -24,7 +24,7 @@ public final class TPEHelper {
   // A ThreadPoolExecutor with one of these types will newer be propagated/wrapped
   private static final Set<String> excludedClasses;
   // A ThreadLocal to store the Scope between beforeExecute and afterExecute if wrapping is not used
-  private static final ThreadLocal<AgentScope> threadLocalScope;
+  private static final ThreadLocal<ContextScope> threadLocalScope;
 
   private static final ClassValue<Boolean> WRAP =
       GenericClassValue.of(
@@ -78,37 +78,37 @@ public static void capture(ContextStore<Runnable, State> contextStore, Runnable
     }
   }
 
-  public static AgentScope startScope(ContextStore<Runnable, State> contextStore, Runnable task) {
+  public static ContextScope startScope(ContextStore<Runnable, State> contextStore, Runnable task) {
     if (task == null || exclude(RUNNABLE, task)) {
       return null;
     }
     return AdviceUtils.startTaskScope(contextStore, task);
   }
 
-  public static void setThreadLocalScope(AgentScope scope, Runnable task) {
+  public static void setThreadLocalScope(ContextScope scope, Runnable task) {
     if (scope == null || task == null || exclude(RUNNABLE, task)) {
       return;
     }
-    AgentScope current = threadLocalScope.get();
+    ContextScope current = threadLocalScope.get();
     if (current != null) {
       current.close();
     }
     threadLocalScope.set(scope);
   }
 
-  public static AgentScope getAndClearThreadLocalScope(Runnable task) {
+  public static ContextScope getAndClearThreadLocalScope(Runnable task) {
     if (task == null || exclude(RUNNABLE, task)) {
       return null;
     }
-    AgentScope scope = threadLocalScope.get();
+    ContextScope scope = threadLocalScope.get();
     // Intentionally use `.set(null)` instead of `.remove()` for performance reasons.
     // For details see: https://github.com/DataDog/dd-trace-java/pull/9856#discussion_r2527729963
     // noinspection ThreadLocalSetWithNull
     threadLocalScope.set(null);
     return scope;
   }
 
-  public static void endScope(AgentScope scope, Runnable task) {
+  public static void endScope(ContextScope scope, Runnable task) {
     if (task == null || exclude(RUNNABLE, task)) {
       return;
     }

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/Wrapper.java

@@ -1,12 +1,12 @@
 package datadog.trace.bootstrap.instrumentation.java.concurrent;
 
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.captureActiveSpan;
-import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.noopContinuation;
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ExcludeFilter.ExcludeType.RUNNABLE;
 import static datadog.trace.bootstrap.instrumentation.java.concurrent.ExcludeFilter.exclude;
 
+import datadog.context.Context;
+import datadog.context.ContextContinuation;
 import datadog.context.ContextScope;
-import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import java.util.concurrent.RunnableFuture;
 
 public class Wrapper<T extends Runnable> implements Runnable, AutoCloseable {
@@ -19,8 +19,8 @@ public static <T extends Runnable> Runnable wrap(T task) {
         || exclude(RUNNABLE, task)) {
       return task;
     }
-    AgentScope.Continuation continuation = captureActiveSpan();
-    if (continuation != noopContinuation()) {
+    ContextContinuation continuation = captureActiveSpan();
+    if (continuation.context() != Context.root()) {
       if (task instanceof Comparable) {
         return new ComparableRunnable(task, continuation);
       }
@@ -35,9 +35,9 @@ public static Runnable unwrap(Runnable task) {
   }
 
   protected final T delegate;
-  private final AgentScope.Continuation continuation;
+  private final ContextContinuation continuation;
 
-  public Wrapper(T delegate, AgentScope.Continuation continuation) {
+  public Wrapper(T delegate, ContextContinuation continuation) {
     this.delegate = delegate;
     this.continuation = continuation;
   }
@@ -51,16 +51,16 @@ public void run() {
 
   public void cancel() {
     if (null != continuation) {
-      continuation.cancel();
+      continuation.release();
     }
   }
 
   public T unwrap() {
     return delegate;
   }
 
-  private AgentScope activate() {
-    return null == continuation ? null : continuation.activate();
+  private ContextScope activate() {
+    return null == continuation ? null : continuation.resume();
   }
 
   @Override