Adding API to copy all parameters from one node to another

rclcpp/include/rclcpp/copy_all_parameters.hpp

@@ -0,0 +1,47 @@
+// Copyright 2023 Open Navigation LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RCLCPP__COPY_ALL_PARAMETERS_HPP_
+#define RCLCPP__COPY_ALL_PARAMETERS_HPP_
+
+#include <vector>
+#include <string>
+#include "rcl_interfaces/srv/list_parameters.hpp"
+#include "rclcpp/parameter.hpp"
+
+namespace rclcpp
+{
+
+/**
+ * @brief A method to copy all parameters from one node (parent) to another (child).
+ * May throw parameter exceptions in error conditions
+ * @param parent Node to copy parameters from
+ * @param child Node to copy parameters to
+ */
+template<typename NodeT1, typename NodeT2>
+void copy_all_parameters(const NodeT1 & parent, const NodeT2 & child)
+{
+  using Parameters = std::vector<rclcpp::Parameter>;
+  std::vector<std::string> param_names = parent->list_parameters({}, 0).names;
+  Parameters params = parent->get_parameters(param_names);
+  for (Parameters::const_iterator iter = params.begin(); iter != params.end(); ++iter) {
+    if (!child->has_parameter(iter->get_name())) {
+      child->declare_parameter(iter->get_name(), iter->get_parameter_value());
+    }
+  }
+}
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__COPY_ALL_PARAMETERS_HPP_

rclcpp/include/rclcpp/rclcpp.hpp

@@ -54,6 +54,7 @@
  *   - rclcpp::ParameterValue
  *   - rclcpp::AsyncParametersClient
  *   - rclcpp::SyncParametersClient
+ *   - rclcpp::copy_all_parameters()
  *   - rclcpp/parameter.hpp
  *   - rclcpp/parameter_value.hpp
  *   - rclcpp/parameter_client.hpp
@@ -164,6 +165,7 @@
 #include <csignal>
 #include <memory>
 
+#include "rclcpp/copy_all_parameters.hpp"
 #include "rclcpp/executors.hpp"
 #include "rclcpp/guard_condition.hpp"
 #include "rclcpp/logging.hpp"

rclcpp/test/rclcpp/CMakeLists.txt

@@ -81,6 +81,13 @@ if(TARGET test_client)
   )
   target_link_libraries(test_client ${PROJECT_NAME} mimick)
 endif()
+ament_add_gtest(test_copy_all_parameters test_copy_all_parameters.cpp)
+if(TARGET test_copy_all_parameters)
+  ament_target_dependencies(test_copy_all_parameters
+    "rcl_interfaces"
+  )
+  target_link_libraries(test_copy_all_parameters ${PROJECT_NAME})
+endif()
 ament_add_gtest(test_create_timer test_create_timer.cpp)
 if(TARGET test_create_timer)
   ament_target_dependencies(test_create_timer

rclcpp/test/rclcpp/test_copy_all_parameters.cpp

@@ -0,0 +1,57 @@
+// Copyright 2023 Open Navigation LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <gtest/gtest.h>
+#include "rclcpp/copy_all_parameters.hpp"
+#include "rclcpp/rclcpp.hpp"
+
+class RclCppFixture
+{
+public:
+  RclCppFixture() {rclcpp::init(0, nullptr);}
+  ~RclCppFixture() {rclcpp::shutdown();}
+};
+RclCppFixture g_rclcppfixture;
+
+TEST(TestParamCopying, TestParamCopying)
+{
+  auto node1 = std::make_shared<rclcpp::Node>("test_node1");
+  auto node2 = std::make_shared<rclcpp::Node>("test_node2");
+
+  // Tests for (1) multiple types, (2) recursion, (3) overriding values
+  node1->declare_parameter("Foo1", rclcpp::ParameterValue(std::string(("bar1"))));
+  node1->declare_parameter("Foo2", rclcpp::ParameterValue(0.123));
+  node1->declare_parameter("Foo", rclcpp::ParameterValue(std::string(("bar"))));
+  node1->declare_parameter("Foo.bar", rclcpp::ParameterValue(std::string(("steve"))));
+  node2->declare_parameter("Foo", rclcpp::ParameterValue(std::string(("barz2"))));
+
+  // Show Node2 is empty of Node1's parameters, but contains its own
+  EXPECT_FALSE(node2->has_parameter("Foo1"));
+  EXPECT_FALSE(node2->has_parameter("Foo2"));
+  EXPECT_FALSE(node2->has_parameter("Foo.bar"));
+  EXPECT_TRUE(node2->has_parameter("Foo"));
+  EXPECT_EQ(node2->get_parameter("Foo").as_string(), std::string("barz2"));
+
+  rclcpp::copy_all_parameters(node1, node2);
+
+  // Test new parameters exist, of expected value, and original param is not overridden
+  EXPECT_TRUE(node2->has_parameter("Foo1"));
+  EXPECT_EQ(node2->get_parameter("Foo1").as_string(), std::string("bar1"));
+  EXPECT_TRUE(node2->has_parameter("Foo2"));
+  EXPECT_EQ(node2->get_parameter("Foo2").as_double(), 0.123);
+  EXPECT_TRUE(node2->has_parameter("Foo.bar"));
+  EXPECT_EQ(node2->get_parameter("Foo.bar").as_string(), std::string("steve"));
+  EXPECT_TRUE(node2->has_parameter("Foo"));
+  EXPECT_EQ(node2->get_parameter("Foo").as_string(), std::string("barz2"));
+}