Add In-Product Enablement (#8587)

Introduce the ability to start and stop Debugger features:
 - Dynamic Instrumentation
 - Exception Replay
 - Code Origin
 - Distributed Debugger
dynamically based on RemoteConfig record: APM_TRACING
DebuggerAgent is now run every time at startup to have the base of
some feature ready and be able to start the minimum required foe each
feature.
Ability to stop also the feature at any time to uninstall probes.
Add smoke tests
Refactor common initialization to be done at least once either by
dynamic Instrumentation, Exception Replay or Code Origin
SourceFile tracking is enabled only if DI or ER is enabled at startup.
Next PR needs to address SourceFile tracking is enabled via In-Product Enablement

Author: jpbempel

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

@@ -101,9 +101,9 @@ private enum AgentFeature {
     CIVISIBILITY_AGENTLESS(CiVisibilityConfig.CIVISIBILITY_AGENTLESS_ENABLED, false),
     USM(UsmConfig.USM_ENABLED, false),
     TELEMETRY(GeneralConfig.TELEMETRY_ENABLED, true),
-    DEBUGGER(DebuggerConfig.DYNAMIC_INSTRUMENTATION_ENABLED, false),
-    EXCEPTION_DEBUGGING(DebuggerConfig.EXCEPTION_REPLAY_ENABLED, false),
-    SPAN_ORIGIN(TraceInstrumentationConfig.CODE_ORIGIN_FOR_SPANS_ENABLED, false),
+    DYNAMIC_INSTRUMENTATION(DebuggerConfig.DYNAMIC_INSTRUMENTATION_ENABLED, false),
+    EXCEPTION_REPLAY(DebuggerConfig.EXCEPTION_REPLAY_ENABLED, false),
+    CODE_ORIGIN(TraceInstrumentationConfig.CODE_ORIGIN_FOR_SPANS_ENABLED, false),
     DATA_JOBS(GeneralConfig.DATA_JOBS_ENABLED, false),
     AGENTLESS_LOG_SUBMISSION(GeneralConfig.AGENTLESS_LOG_SUBMISSION_ENABLED, false);
 
@@ -154,9 +154,10 @@ public boolean isEnabledByDefault() {
   private static boolean ciVisibilityEnabled = false;
   private static boolean usmEnabled = false;
   private static boolean telemetryEnabled = true;
-  private static boolean debuggerEnabled = false;
-  private static boolean exceptionDebuggingEnabled = false;
-  private static boolean spanOriginEnabled = false;
+  private static boolean dynamicInstrumentationEnabled = false;
+  private static boolean exceptionReplayEnabled = false;
+  private static boolean codeOriginEnabled = false;
+  private static boolean distributedDebuggerEnabled = false;
   private static boolean agentlessLogSubmissionEnabled = false;
 
   /**
@@ -272,9 +273,9 @@ public static void start(
             || isFeatureEnabled(AgentFeature.DEPRECATED_REMOTE_CONFIG);
     cwsEnabled = isFeatureEnabled(AgentFeature.CWS);
     telemetryEnabled = isFeatureEnabled(AgentFeature.TELEMETRY);
-    debuggerEnabled = isFeatureEnabled(AgentFeature.DEBUGGER);
-    exceptionDebuggingEnabled = isFeatureEnabled(AgentFeature.EXCEPTION_DEBUGGING);
-    spanOriginEnabled = isFeatureEnabled(AgentFeature.SPAN_ORIGIN);
+    dynamicInstrumentationEnabled = isFeatureEnabled(AgentFeature.DYNAMIC_INSTRUMENTATION);
+    exceptionReplayEnabled = isFeatureEnabled(AgentFeature.EXCEPTION_REPLAY);
+    codeOriginEnabled = isFeatureEnabled(AgentFeature.CODE_ORIGIN);
     agentlessLogSubmissionEnabled = isFeatureEnabled(AgentFeature.AGENTLESS_LOG_SUBMISSION);
 
     if (profilingEnabled) {
@@ -1133,7 +1134,10 @@ private static void shutdownProfilingAgent(final boolean sync) {
   }
 
   private static void maybeStartDebugger(Instrumentation inst, Class<?> scoClass, Object sco) {
-    if (!debuggerEnabled && !exceptionDebuggingEnabled && !spanOriginEnabled) {
+    if (isExplicitlyDisabled(DebuggerConfig.DYNAMIC_INSTRUMENTATION_ENABLED)
+        && isExplicitlyDisabled(DebuggerConfig.EXCEPTION_REPLAY_ENABLED)
+        && isExplicitlyDisabled(TraceInstrumentationConfig.CODE_ORIGIN_FOR_SPANS_ENABLED)
+        && isExplicitlyDisabled(DebuggerConfig.DISTRIBUTED_DEBUGGER_ENABLED)) {
       return;
     }
     if (!remoteConfigEnabled) {
@@ -1143,6 +1147,11 @@ private static void maybeStartDebugger(Instrumentation inst, Class<?> scoClass,
     startDebuggerAgent(inst, scoClass, sco);
   }
 
+  private static boolean isExplicitlyDisabled(String booleanKey) {
+    return Config.get().configProvider().isSet(booleanKey)
+        && !Config.get().configProvider().getBoolean(booleanKey);
+  }
+
   private static synchronized void startDebuggerAgent(
       Instrumentation inst, Class<?> scoClass, Object sco) {
     StaticEventLogger.begin("Debugger");

dd-java-agent/agent-debugger/debugger-bootstrap/src/main/java/datadog/trace/bootstrap/debugger/DebuggerContext.java

@@ -50,6 +50,22 @@ public String tag() {
     public abstract String tag();
   }
 
+  public interface ProductConfigUpdater {
+    void updateConfig(
+        Boolean dynamicInstrumentationEnabled,
+        Boolean exceptionReplayEnabled,
+        Boolean codeOriginEnabled,
+        Boolean liveDebuggingEnabled);
+
+    boolean isDynamicInstrumentationEnabled();
+
+    boolean isExceptionReplayEnabled();
+
+    boolean isCodeOriginEnabled();
+
+    boolean isDistributedDebuggerEnabled();
+  }
+
   public interface ProbeResolver {
     ProbeImplementation resolve(String encodedProbeId);
   }
@@ -103,6 +119,7 @@ public interface CodeOriginRecorder {
     String captureCodeOrigin(Method method, boolean entry, boolean instrument);
   }
 
+  private static volatile ProductConfigUpdater productConfigUpdater;
   private static volatile ProbeResolver probeResolver;
   private static volatile ClassFilter classFilter;
   private static volatile ClassNameFilter classNameFilter;
@@ -112,6 +129,10 @@ public interface CodeOriginRecorder {
   private static volatile ExceptionDebugger exceptionDebugger;
   private static volatile CodeOriginRecorder codeOriginRecorder;
 
+  public static void initProductConfigUpdater(ProductConfigUpdater productConfigUpdater) {
+    DebuggerContext.productConfigUpdater = productConfigUpdater;
+  }
+
   public static void initProbeResolver(ProbeResolver probeResolver) {
     DebuggerContext.probeResolver = probeResolver;
   }
@@ -144,6 +165,59 @@ public static void initCodeOrigin(CodeOriginRecorder codeOriginRecorder) {
     DebuggerContext.codeOriginRecorder = codeOriginRecorder;
   }
 
+  public static void updateConfig(
+      Boolean dynamicInstrumentationEnabled,
+      Boolean exceptionReplayEnabled,
+      Boolean codeOriginEnabled,
+      Boolean liveDebuggingEnabled) {
+    LOGGER.debug(
+        "Updating config: dynamicInstrumentationEnabled: {}, exceptionReplayEnabled: {}, codeOriginEnabled: {}, liveDebuggingEnabled: {}",
+        dynamicInstrumentationEnabled,
+        exceptionReplayEnabled,
+        codeOriginEnabled,
+        liveDebuggingEnabled);
+    ProductConfigUpdater updater = productConfigUpdater;
+    if (updater != null) {
+      updater.updateConfig(
+          dynamicInstrumentationEnabled,
+          exceptionReplayEnabled,
+          codeOriginEnabled,
+          liveDebuggingEnabled);
+    }
+  }
+
+  public static boolean isDynamicInstrumentationEnabled() {
+    ProductConfigUpdater updater = productConfigUpdater;
+    if (updater != null) {
+      return updater.isDynamicInstrumentationEnabled();
+    }
+    return Config.get().isDynamicInstrumentationEnabled();
+  }
+
+  public static boolean isExceptionReplayEnabled() {
+    ProductConfigUpdater updater = productConfigUpdater;
+    if (updater != null) {
+      return updater.isExceptionReplayEnabled();
+    }
+    return Config.get().isDebuggerExceptionEnabled();
+  }
+
+  public static boolean isCodeOriginEnabled() {
+    ProductConfigUpdater updater = productConfigUpdater;
+    if (updater != null) {
+      return updater.isCodeOriginEnabled();
+    }
+    return Config.get().isDebuggerCodeOriginEnabled();
+  }
+
+  public static boolean isDistributedDebuggerEnabled() {
+    ProductConfigUpdater updater = productConfigUpdater;
+    if (updater != null) {
+      return updater.isDistributedDebuggerEnabled();
+    }
+    return Config.get().isDistributedDebuggerEnabled();
+  }
+
   /**
    * Returns the probe details based on the probe id provided. If no probe is found, try to
    * re-transform the class using the callingClass parameter No-op if no implementation available