Add Topic Statistics Example

rclcpp/topics/minimal_subscriber/CMakeLists.txt

@@ -20,12 +20,16 @@ ament_target_dependencies(subscriber_lambda rclcpp std_msgs)
 add_executable(subscriber_member_function member_function.cpp)
 ament_target_dependencies(subscriber_member_function rclcpp std_msgs)
 
+add_executable(subscriber_member_function_with_topic_statistics member_function_with_topic_statistics.cpp)
+ament_target_dependencies(subscriber_member_function_with_topic_statistics rclcpp std_msgs)
+
 add_executable(subscriber_not_composable not_composable.cpp)
 ament_target_dependencies(subscriber_not_composable rclcpp std_msgs)
 
 install(TARGETS
   subscriber_lambda
   subscriber_member_function
+  subscriber_member_function_with_topic_statistics
   subscriber_not_composable
   DESTINATION lib/${PROJECT_NAME})
 

rclcpp/topics/minimal_subscriber/member_function_with_topic_statistics.cpp

@@ -0,0 +1,61 @@
+// 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 <chrono>
+#include <memory>
+
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp/subscription_options.hpp"
+
+#include "std_msgs/msg/string.hpp"
+
+class MinimalSubscriberWithTopicStatistics : public rclcpp::Node
+{
+public:
+  MinimalSubscriberWithTopicStatistics()
+  : Node("minimal_subscriber_with_topic_statistics")
+  {
+    // manually enable topic statistics via options
+    auto options = rclcpp::SubscriptionOptions();
+    options.topic_stats_options.state = rclcpp::TopicStatisticsState::Enable;
+
+    // configure the collection window and publish period (default 1s)
+    options.topic_stats_options.publish_period = std::chrono::seconds(10);
+
+    // configure the topic name (default '/statistics')
+    // options.topic_stats_options.publish_topic = "/topic_statistics"
+
+    auto callback = [this](std_msgs::msg::String::SharedPtr msg) {
+        this->topic_callback(msg);
+      };
+
+    subscription_ = this->create_subscription<std_msgs::msg::String>(
+      "topic", 10, callback, options);
+  }
+
+private:
+  void topic_callback(const std_msgs::msg::String::SharedPtr msg) const
+  {
+    RCLCPP_INFO(this->get_logger(), "I heard: '%s'", msg->data.c_str());
+  }
+  rclcpp::Subscription<std_msgs::msg::String>::SharedPtr subscription_;
+};
+
+int main(int argc, char * argv[])
+{
+  rclcpp::init(argc, argv);
+  rclcpp::spin(std::make_shared<MinimalSubscriberWithTopicStatistics>());
+  rclcpp::shutdown();
+  return 0;
+}