JAVA-3046: Extend RequestTracker interface for observability

Co-authored-by: Andrew Tolbert <6889771+tolbertam@users.noreply.github.com>

Author: lukasz-antoniak

core/src/main/java/com/datastax/dse/driver/internal/core/cql/continuous/ContinuousRequestHandlerBase.java

@@ -834,7 +834,7 @@ private void processResultResponse(@NonNull Result result, @Nullable Frame frame
       assert lock.isHeldByCurrentThread();
       try {
         ExecutionInfo executionInfo =
-            createExecutionInfo().withServerResponse(result, frame).build();
+            createExecutionInfo(null).withServerResponse(result, frame).build();
         if (result instanceof Rows) {
           DseRowsMetadata rowsMetadata = (DseRowsMetadata) ((Rows) result).getMetadata();
           if (columnDefinitions == null) {
@@ -1459,7 +1459,7 @@ private void trackNodeError(
                 latencyNanos,
                 executionProfile,
                 node,
-                createExecutionInfo().withServerResponse(frame).build(),
+                createExecutionInfo(error).withServerResponse(frame).build(),
                 logPrefix);
       }
     }
@@ -1613,12 +1613,13 @@ private void completeResultSetFuture(
     }
 
     @NonNull
-    private DefaultExecutionInfo.Builder createExecutionInfo() {
+    private DefaultExecutionInfo.Builder createExecutionInfo(Throwable error) {
       return DefaultExecutionInfo.builder(
           statement,
           node,
           startedSpeculativeExecutionsCount.get(),
           executionIndex,
+          error,
           errors,
           session,
           context,

core/src/main/java/com/datastax/dse/driver/internal/core/graph/GraphRequestHandler.java

@@ -335,6 +335,7 @@ private void setFinalResult(
                   callback.node,
                   startedSpeculativeExecutionsCount.get(),
                   callback.execution,
+                  null,
                   errors,
                   session,
                   context,
@@ -456,6 +457,7 @@ private void setFinalError(
                 node,
                 startedSpeculativeExecutionsCount.get(),
                 execution,
+                error,
                 errors,
                 session,
                 context,

core/src/main/java/com/datastax/oss/driver/api/core/cql/ExecutionInfo.java

@@ -120,6 +120,11 @@ default DriverExecutionProfile getExecutionProfile() {
   @NonNull
   List<Map.Entry<Node, Throwable>> getErrors();
 
+  @Nullable
+  default Throwable getDriverError() {
+    return null;
+  }
+
   /**
    * The paging state of the query, in its raw form.
    *

core/src/main/java/com/datastax/oss/driver/api/core/tracker/RequestTracker.java

@@ -36,6 +36,33 @@
  */
 public interface RequestTracker extends AutoCloseable {
 
+  /**
+   * Invoked each time new request is created.
+   *
+   * @param request the request to be executed
+   * @param executionProfile the execution profile of this request
+   * @param requestLogPrefix the dedicated log prefix for this request
+   */
+  default void onRequestCreated(
+      @NonNull Request request,
+      @NonNull DriverExecutionProfile executionProfile,
+      @NonNull String requestLogPrefix) {}
+
+  /**
+   * Invoked each time a new request is created and sent to next node. Due to retry policy, this
+   * method can be triggered multiple times while processing one logical request.
+   *
+   * @param request the request to be executed
+   * @param executionProfile the execution profile of this request
+   * @param node the node which will receive the request
+   * @param requestLogPrefix the dedicated log prefix for this request
+   */
+  default void onRequestCreatedForNode(
+      @NonNull Request request,
+      @NonNull DriverExecutionProfile executionProfile,
+      @NonNull Node node,
+      @NonNull String requestLogPrefix) {}
+
   /**
    * Invoked each time a request succeeds.
    *
@@ -71,6 +98,7 @@ default void onSuccess(
   default void onError(
       @NonNull Request request,
       @NonNull Throwable error,
+      // TODO: Shall we expose start and end timestamp so that users do not need to call nanoTime()?
       long latencyNanos,
       @NonNull DriverExecutionProfile executionProfile,
       @Nullable Node node,

core/src/main/java/com/datastax/oss/driver/internal/core/cql/Conversions.java

@@ -74,6 +74,7 @@
 import com.datastax.oss.protocol.internal.ProtocolConstants;
 import com.datastax.oss.protocol.internal.request.Batch;
 import com.datastax.oss.protocol.internal.request.Execute;
+import com.datastax.oss.protocol.internal.request.Prepare;
 import com.datastax.oss.protocol.internal.request.Query;
 import com.datastax.oss.protocol.internal.request.query.QueryOptions;
 import com.datastax.oss.protocol.internal.response.Error;
@@ -359,6 +360,10 @@ public static ColumnDefinitions getResultDefinitions(
     }
   }
 
+  public static PrepareRequest toPrepareRequest(Prepare request) {
+    return new DefaultPrepareRequest(SimpleStatement.newInstance(request.cqlQuery));
+  }
+
   public static DefaultPreparedStatement toPreparedStatement(
       Prepared response, PrepareRequest request, InternalDriverContext context) {
     ColumnDefinitions variableDefinitions =