DartSqlResource: Return HTTP 202 on cancellation even if no such quer…

…y. (apache#17278)

Return HTTP 202 (Accepted) on cancellation, even if the requested query
ID was not found.

The main reason for this is that when the Router broadcasts DELETE requests
to all Brokers, it returns the response from one of them randomly. If we
return 404 when a query ID isn't found, then the Router randomly returns 404s
even when the query really was found and canceled.

This is also arguably still correct behavior. The cancellation request
*was* accepted, it just won't do anything because the query was not in
fact running.

extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/dart/controller/http/DartSqlResource.java

@@ -239,7 +239,10 @@ public Response cancelQuery(
 
     List<SqlLifecycleManager.Cancelable> cancelables = sqlLifecycleManager.getAll(sqlQueryId);
     if (cancelables.isEmpty()) {
-      return Response.status(Response.Status.NOT_FOUND).build();
+      // Return ACCEPTED even if the query wasn't found. When the Router broadcasts cancellation requests to all
+      // Brokers, this ensures the user sees a successful request.
+      AuthorizationUtils.setRequestAuthorizationAttributeIfNeeded(req);
+      return Response.status(Response.Status.ACCEPTED).build();
     }
 
     final Access access = authorizeCancellation(req, cancelables);
@@ -249,14 +252,12 @@ public Response cancelQuery(
 
       // Don't call cancel() on the cancelables. That just cancels native queries, which is useless here. Instead,
       // get the controller and stop it.
-      boolean found = false;
       for (SqlLifecycleManager.Cancelable cancelable : cancelables) {
         final HttpStatement stmt = (HttpStatement) cancelable;
         final Object dartQueryId = stmt.context().get(DartSqlEngine.CTX_DART_QUERY_ID);
         if (dartQueryId instanceof String) {
           final ControllerHolder holder = controllerRegistry.get((String) dartQueryId);
           if (holder != null) {
-            found = true;
             holder.cancel();
           }
         } else {
@@ -269,7 +270,9 @@ public Response cancelQuery(
         }
       }
 
-      return Response.status(found ? Response.Status.ACCEPTED : Response.Status.NOT_FOUND).build();
+      // Return ACCEPTED even if the query wasn't found. When the Router broadcasts cancellation requests to all
+      // Brokers, this ensures the user sees a successful request.
+      return Response.status(Response.Status.ACCEPTED).build();
     } else {
       return Response.status(Response.Status.FORBIDDEN).build();
     }

extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/dart/controller/http/DartSqlResourceTest.java

@@ -727,7 +727,7 @@ public void test_cancelQuery_regularUser_unknownQuery()
            .thenReturn(makeAuthenticationResult(REGULAR_USER_NAME));
 
     final Response cancellationResponse = sqlResource.cancelQuery("nonexistent", httpServletRequest);
-    Assertions.assertEquals(Response.Status.NOT_FOUND.getStatusCode(), cancellationResponse.getStatus());
+    Assertions.assertEquals(Response.Status.ACCEPTED.getStatusCode(), cancellationResponse.getStatus());
   }
 
   /**