ParameterEventHandler support ContentFiltering

rclcpp/include/rclcpp/parameter_event_handler.hpp

@@ -234,6 +234,10 @@ class ParameterEventHandler
   /**
    * If a node_name is not provided, defaults to the current node.
    *
+   * The configure_nodes_filter() function will affect the behavior of this function.
+   * If the node specified in this function isn't included in the nodes specified in
+   * configure_nodes_filter(), the callback will never be called.
+   *
    * Note: if the returned callback handle smart pointer is not captured, the callback
    * is immediately unregistered. A compiler warning should be generated to warn
    * of this.
@@ -251,6 +255,31 @@ class ParameterEventHandler
     ParameterCallbackType callback,
     const std::string & node_name = "");
 
+  /// Configure which node parameter events will be received.
+  /**
+   * This function depends on rmw implementation support for content filtering.
+   * If middleware doesn't support contentfilter, return false.
+   *
+   * If node_names is empty, the configured node filter will be cleared.
+   *
+   * If this function return true, only parameter events from the specified node will be received.
+   * It affects the behavior of the following two functions.
+   * - add_parameter_event_callback()
+   *   The callback will only be called for parameter events from the specified nodes which are
+   *   configured in this function.
+   * - add_parameter_callback()
+   *   The callback will only be called for parameter events from the specified nodes which are
+   *   configured in this function and add_parameter_callback().
+   *   If the nodes specified in this function is different from the nodes specified in
+   *   add_parameter_callback(), the callback will never be called.
+   *
+   * \param[in] node_names Node names to filter parameter events from.
+   * \returns true if configuring was successfully applied, false otherwise.
+   * \throws rclcpp::exceptions::RCLError if internal error occurred when calling the rcl function.
+   */
+  RCLCPP_PUBLIC
+  bool configure_nodes_filter(const std::vector<std::string> & node_names);
+
   /// Remove a parameter callback registered with add_parameter_callback.
   /**
    * The parameter name and node name are inspected from the callback handle. The callback handle

rclcpp/src/rclcpp/parameter_event_handler.cpp

@@ -74,6 +74,38 @@ ParameterEventHandler::add_parameter_callback(
   return handle;
 }
 
+bool
+ParameterEventHandler::configure_nodes_filter(const std::vector<std::string> & node_names)
+{
+  if (node_names.empty()) {
+    // Clear content filter
+    event_subscription_->set_content_filter("");
+    if (event_subscription_->is_cft_enabled()) {
+      return false;
+    }
+    return true;
+  }
+
+  std::string filter_expression;
+  size_t total = node_names.size();
+  for (size_t i = 0; i < total; ++i) {
+    filter_expression += "node = %" + std::to_string(i);
+    if (i < total - 1) {
+      filter_expression += " OR ";
+    }
+  }
+
+  // Enclose each node name in "'".
+  std::vector<std::string> quoted_node_names;
+  for (const auto & name : node_names) {
+    quoted_node_names.push_back("'" + resolve_path(name) + "'");
+  }
+
+  event_subscription_->set_content_filter(filter_expression, quoted_node_names);
+
+  return event_subscription_->is_cft_enabled();
+}
+
 void
 ParameterEventHandler::remove_parameter_callback(
   ParameterCallbackHandle::SharedPtr callback_handle)

rclcpp/test/rclcpp/test_parameter_event_handler.cpp

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <atomic>
 #include <chrono>
 #include <memory>
 #include <string>
@@ -20,6 +21,8 @@
 #include "gtest/gtest.h"
 #include "rclcpp/rclcpp.hpp"
 
+using namespace std::chrono_literals;
+
 class TestParameterEventHandler : public rclcpp::ParameterEventHandler
 {
 public:
@@ -443,3 +446,199 @@ TEST_F(TestNode, LastInFirstCallForParameterEventCallbacks)
   param_handler->remove_parameter_event_callback(h2);
   EXPECT_EQ(param_handler->num_event_callbacks(), 0UL);
 }
+
+TEST_F(TestNode, ConfigureNodesFilterAndCheckAddParameterEventCallback)
+{
+  std::string rmw_implementation_str = std::string(rmw_get_implementation_identifier());
+  if (rmw_implementation_str != "rmw_fastrtps_cpp" && rmw_implementation_str != "rmw_connextdds") {
+    GTEST_SKIP() << "Content filter is now only supported in FastDDS and ConnextDDS.";
+  }
+
+  const std::string remote_node_name1 = "remote_node1";
+  const std::string remote_node_name2 = "remote_node2";
+  rclcpp::NodeOptions options;
+  options.enable_rosout(false);
+  auto remote_node1 = std::make_shared<rclcpp::Node>(
+    remote_node_name1, options);
+  auto remote_node2 = std::make_shared<rclcpp::Node>(
+    remote_node_name2, options);
+
+  const std::string remote_node1_param_name = "param_node1";
+  const std::string remote_node2_param_name = "param_node2";
+  remote_node1->declare_parameter(remote_node1_param_name, 10);
+  remote_node2->declare_parameter(remote_node2_param_name, "Default");
+
+  std::atomic_bool received_from_remote_node1{false};
+  std::atomic_bool received_from_remote_node2{false};
+
+  auto cb =
+    [&remote_node_name1, &remote_node_name2, &received_from_remote_node1,
+      &received_from_remote_node2]
+    (const rcl_interfaces::msg::ParameterEvent & parm) {
+      if (parm.node == "/" + remote_node_name1) {
+        received_from_remote_node1 = true;
+      } else if (parm.node == "/" + remote_node_name2) {
+        received_from_remote_node2 = true;
+      }
+    };
+
+  // Configure to only receive parameter events from remote_node_name2
+  ASSERT_TRUE(param_handler->configure_nodes_filter({remote_node_name2}));
+
+  auto handler = param_handler->add_parameter_event_callback(cb);
+
+  rclcpp::executors::SingleThreadedExecutor executor;
+  executor.add_node(node);
+  executor.add_node(remote_node1);
+  executor.add_node(remote_node2);
+
+  auto wait_param_event = [&executor]
+    (std::chrono::seconds timeout, std::function<bool()> condition = nullptr) {
+      auto start = std::chrono::steady_clock::now();
+      while (std::chrono::steady_clock::now() - start < timeout) {
+        executor.spin_some();
+        if (condition && condition()) {
+          break;
+        }
+        std::this_thread::sleep_for(100ms);
+      }
+    };
+
+  {
+    std::thread thread(wait_param_event, 1s, nullptr);
+    std::this_thread::sleep_for(100ms);
+    remote_node1->set_parameter(rclcpp::Parameter(remote_node1_param_name, 20));
+    remote_node2->set_parameter(rclcpp::Parameter(remote_node2_param_name, "abc"));
+    thread.join();
+  }
+
+  EXPECT_EQ(received_from_remote_node1, false);
+  EXPECT_EQ(received_from_remote_node2, true);
+
+  // Clear node filter and all parameter events from remote nodes should be received
+  ASSERT_TRUE(param_handler->configure_nodes_filter({}));
+
+  received_from_remote_node1 = false;
+  received_from_remote_node2 = false;
+
+  {
+    std::thread thread(
+      wait_param_event,
+      2s,
+      [&received_from_remote_node1, &received_from_remote_node2]() {
+        if (received_from_remote_node1 && received_from_remote_node2) {
+          return true;
+        }
+        return false;
+      });
+    std::this_thread::sleep_for(100ms);
+    remote_node1->set_parameter(rclcpp::Parameter(remote_node1_param_name, 30));
+    remote_node2->set_parameter(rclcpp::Parameter(remote_node2_param_name, "def"));
+    thread.join();
+  }
+
+  EXPECT_EQ(received_from_remote_node1, true);
+  EXPECT_EQ(received_from_remote_node2, true);
+}
+
+TEST_F(TestNode, ConfigureNodesFilterAndCheckAddParameterCallback)
+{
+  std::string rmw_implementation_str = std::string(rmw_get_implementation_identifier());
+  if (rmw_implementation_str != "rmw_fastrtps_cpp" && rmw_implementation_str != "rmw_connextdds") {
+    GTEST_SKIP() << "Content filter is now only supported in FastDDS and ConnextDDS.";
+  }
+
+  const std::string remote_node_name1 = "remote_node1";
+  const std::string remote_node_name2 = "remote_node2";
+  rclcpp::NodeOptions options;
+  options.enable_rosout(false);
+  auto remote_node1 = std::make_shared<rclcpp::Node>(
+    remote_node_name1, options);
+  auto remote_node2 = std::make_shared<rclcpp::Node>(
+    remote_node_name2, options);
+
+  const std::string remote_node1_param_name = "param_node1";
+  const std::string remote_node2_param_name = "param_node2";
+  remote_node1->declare_parameter(remote_node1_param_name, 10);
+  remote_node2->declare_parameter(remote_node2_param_name, "Default");
+
+  std::atomic_bool received_from_remote_node1{false};
+  std::atomic_bool received_from_remote_node2{false};
+
+  auto cb_remote_node1 =
+    [&remote_node1_param_name, &received_from_remote_node1]
+    (const rclcpp::Parameter & parm) {
+      if (parm.get_name() == remote_node1_param_name) {
+        received_from_remote_node1 = true;
+      }
+    };
+
+  auto cb_remote_node2 =
+    [&remote_node2_param_name, &received_from_remote_node2]
+    (const rclcpp::Parameter & parm) {
+      if (parm.get_name() == remote_node2_param_name) {
+        received_from_remote_node2 = true;
+      }
+    };
+
+  // Configure to only receive parameter events from remote_node_name2
+  ASSERT_TRUE(param_handler->configure_nodes_filter({remote_node_name2}));
+
+  auto handler1 = param_handler->add_parameter_callback(
+    remote_node1_param_name, cb_remote_node1, remote_node_name1);
+  auto handler2 = param_handler->add_parameter_callback(
+    remote_node2_param_name, cb_remote_node2, remote_node_name2);
+
+  rclcpp::executors::SingleThreadedExecutor executor;
+  executor.add_node(node);
+  executor.add_node(remote_node1);
+  executor.add_node(remote_node2);
+
+  auto wait_param_event = [&executor]
+    (std::chrono::seconds timeout, std::function<bool()> condition = nullptr) {
+      auto start = std::chrono::steady_clock::now();
+      while (std::chrono::steady_clock::now() - start < timeout) {
+        executor.spin_some();
+        if (condition && condition()) {
+          break;
+        }
+        std::this_thread::sleep_for(100ms);
+      }
+    };
+
+  {
+    std::thread thread(wait_param_event, 1s, nullptr);
+    std::this_thread::sleep_for(100ms);
+    remote_node1->set_parameter(rclcpp::Parameter(remote_node1_param_name, 20));
+    remote_node2->set_parameter(rclcpp::Parameter(remote_node2_param_name, "abc"));
+    thread.join();
+  }
+
+  EXPECT_EQ(received_from_remote_node1, false);
+  EXPECT_EQ(received_from_remote_node2, true);
+
+  // Clear node filter and all parameter events from remote nodes should be received
+  ASSERT_TRUE(param_handler->configure_nodes_filter({}));
+
+  received_from_remote_node1 = false;
+  received_from_remote_node2 = false;
+
+  {
+    std::thread thread(
+      wait_param_event,
+      2s,
+      [&received_from_remote_node1, &received_from_remote_node2]() {
+        if (received_from_remote_node1 && received_from_remote_node2) {
+          return true;
+        }
+        return false;
+      });
+    std::this_thread::sleep_for(100ms);
+    remote_node1->set_parameter(rclcpp::Parameter(remote_node1_param_name, 30));
+    remote_node2->set_parameter(rclcpp::Parameter(remote_node2_param_name, "def"));
+    thread.join();
+  }
+
+  EXPECT_EQ(received_from_remote_node1, true);
+  EXPECT_EQ(received_from_remote_node2, true);
+}