Add DummyMessage talker node and launch file for it

system_metrics_collector/CMakeLists.txt

@@ -87,6 +87,10 @@ add_executable(linux_memory_collector src/system_metrics_collector/linux_memory_
 target_link_libraries(linux_memory_collector ${PROJECT_NAME})
 ament_target_dependencies(linux_memory_collector)
 
+add_executable(dummy_talker src/topic_statistics_collector/dummy_talker.cpp)
+target_link_libraries(dummy_talker system_metrics_collector)
+ament_target_dependencies(dummy_talker)
+
 if(BUILD_TESTING)
   find_package(ament_lint_auto REQUIRED)
   find_package(ament_cmake_gtest REQUIRED)
@@ -140,8 +144,9 @@ if(BUILD_TESTING)
   ament_target_dependencies(test_subscriber_topic_statistics rcl rclcpp)
 endif()
 
-# To enable use of dummy_message.hpp in test_subscriber_topic_statistics
+# To enable use of dummy_message.hpp in executables
 rosidl_target_interfaces(test_subscriber_topic_statistics system_metrics_collector_test_msgs "rosidl_typesupport_cpp")
+rosidl_target_interfaces(dummy_talker system_metrics_collector_test_msgs "rosidl_typesupport_cpp")
 
 # Install launch files
 install(DIRECTORY
@@ -168,6 +173,12 @@ install(TARGETS
   lib/${PROJECT_NAME}
 )
 
+install(TARGETS
+  dummy_talker
+  DESTINATION
+  lib/${PROJECT_NAME}
+)
+
 install(TARGETS
   ${PROJECT_NAME}
   DESTINATION

system_metrics_collector/share/system_metrics_collector/examples/dummy_talker.launch.py

@@ -0,0 +1,27 @@
+# Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# 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.
+
+"""Launch file to launch a DummyMessage publisher node."""
+
+from launch import LaunchDescription
+import launch_ros.actions
+
+
+def generate_launch_description():
+    return LaunchDescription([
+        launch_ros.actions.Node(
+            package='system_metrics_collector',
+            node_executable='dummy_talker',
+            output='screen'),
+    ])

system_metrics_collector/src/topic_statistics_collector/dummy_talker.cpp

@@ -0,0 +1,76 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// 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 <memory>
+#include <mutex>
+#include <utility>
+
+#include "system_metrics_collector/msg/dummy_message.hpp"
+
+#include "rclcpp/rclcpp.hpp"
+
+/**
+ * A class that publishes DummyMessages every second with the Header set to current time.
+ */
+class DummyTalker : public rclcpp::Node
+{
+public:
+  DummyTalker()
+  : Node("dummy_talker")
+  {
+    using namespace std::chrono_literals;
+    auto publish_lambda =
+      [this]() -> void
+      {
+        std::unique_lock<std::mutex> ulock{mutex_};
+
+        msg_ = std::make_unique<system_metrics_collector::msg::DummyMessage>();
+        msg_->header = std_msgs::msg::Header{};
+        msg_->header.stamp = this->now();
+        RCLCPP_INFO(
+          this->get_logger(),
+          "Publishing header: %lu",
+          msg_->header.stamp.nanosec);
+
+        publisher_->publish(std::move(msg_));
+      };
+
+    publisher_ = this->create_publisher<system_metrics_collector::msg::DummyMessage>(
+      "dummy_data",
+      10 /* QoS history_depth */);
+    timer_ = this->create_wall_timer(1s, publish_lambda);
+  }
+
+private:
+  std::unique_ptr<system_metrics_collector::msg::DummyMessage> msg_;
+  rclcpp::Publisher<system_metrics_collector::msg::DummyMessage>::SharedPtr publisher_;
+  rclcpp::TimerBase::SharedPtr timer_;
+  mutable std::mutex mutex_;
+};
+
+int main(int argc, char ** argv)
+{
+  rclcpp::init(argc, argv);
+
+  const auto dummy_talker =
+    std::make_shared<DummyTalker>();
+
+  rclcpp::executors::SingleThreadedExecutor ex;
+  ex.add_node(dummy_talker->get_node_base_interface());
+  ex.spin();
+
+  rclcpp::shutdown();
+
+  return 0;
+}