...
moveit_msgs::Constraints constraint;
constraint.name = "test";

Eigen::Quaterniond quat = Eigen::AngleAxisd(0, Eigen::Vector3d::UnitZ()) *
                          Eigen::AngleAxisd(M_PI_2, Eigen::Vector3d::UnitY()) *
                          Eigen::AngleAxisd(0, Eigen::Vector3d::UnitX());

moveit_msgs::OrientationConstraint oc;
oc.header.frame_id = "optical_table";
oc.link_name = "object_name";  // Object that is attached to the eef
oc.orientation.w = quat.w();
oc.orientation.x = quat.x();
oc.orientation.y = quat.y();
oc.orientation.z = quat.z();

oc.absolute_x_axis_tolerance = 2 * M_PI;
oc.absolute_y_axis_tolerance = 0.4;
oc.absolute_z_axis_tolerance = 0.4;
oc.weight = 100;
constraint.orientation_constraints.push_back(oc);

stage->setPathConstraints(std::move(constraint));
...

group.clearPoseTargets();
group.setEndEffectorLink(end_effector_link);
/*
group.setEndEffectorLink("cylinder/tip");    // Example 1
group.setEndEffectorLink("panda_hand");      // Example 2
*/
group.setStartStateToCurrentState();
group.setPoseTarget(pose);