Create new topic statistics demo package (#454)

* Create new topic statistics demo package

Signed-off-by: Prajakta Gokhale <[email protected]>

* Remove dependencies

Signed-off-by: Prajakta Gokhale <[email protected]>

* Add demo files

Signed-off-by: Prajakta Gokhale <[email protected]>

* Add uniform distribution to msg age calculation

Signed-off-by: Prajakta Gokhale <[email protected]>

* Log when timestamp offset is added

Signed-off-by: Prajakta Gokhale <[email protected]>

Author: Prajakta Gokhale

topic_statistics_demo/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.5)
+
+project(topic_statistics_demo)
+
+# Default to C++14
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 14)
+endif()
+
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+find_package(ament_cmake REQUIRED)
+find_package(rclcpp REQUIRED)
+find_package(rcutils)
+find_package(sensor_msgs REQUIRED)
+find_package(statistics_msgs REQUIRED)
+
+include_directories(include)
+ament_export_include_directories(include)
+
+add_executable(display_topic_statistics
+  src/imu_talker_listener_nodes.cpp
+  src/display_topic_statistics.cpp
+  src/string_talker_listener_nodes.cpp
+  src/topic_statistics_listener.cpp)
+ament_target_dependencies(display_topic_statistics
+  "rclcpp"
+  "rcutils"
+  "sensor_msgs"
+  "statistics_msgs")
+install(TARGETS display_topic_statistics DESTINATION lib/${PROJECT_NAME})
+
+if(BUILD_TESTING)
+  find_package(ament_lint_auto REQUIRED)
+  ament_lint_auto_find_test_dependencies()
+endif()
+
+ament_package()

topic_statistics_demo/README.md

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+# Topic Statistics Demo
+
+The demo application in this package demonstrates [Topic Statistics](https://index.ros.org/doc/ros2/Concepts/About-Topic-Statistics/) feature in ROS 2.
+The application creates ROS 2 nodes to publish messages to topics, subscribes to the statistics topic and displays the statistics data received.
+
+The demo application in this package `display_topic_statistics` creates the following ROS 2 nodes:
+1. Talker and Listener nodes to generate message traffic
+2. Statistics listener node to display generated statistics
+
+The application requires an argument `message_type` - the type of message chatter to generate.
+Possible values are `string` and `imu`.
+
+The application also accepts the following optional arguments to configure the Listener node's subscription:
+1. `--publish-topic`: Topic to which topic statistics are published. Default topic is `/statistics`.
+2. `--publish-period`: Publish period for publication of statistics. Default value is 5s.
+
+Once the application starts, the talker node will publish messages on a topic that the listener node has subscribed to.
+The listener's subscription will generate topic statistics upon receiving messages.
+Statistics are published to the statistics topic at a pre-determined frequency.
+The statistics listener node listens to these statistics and prints them for the user to see.

topic_statistics_demo/include/topic_statistics_demo/imu_talker_listener_nodes.hpp

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+// 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.
+
+#ifndef TOPIC_STATISTICS_DEMO__IMU_TALKER_LISTENER_NODES_HPP_
+#define TOPIC_STATISTICS_DEMO__IMU_TALKER_LISTENER_NODES_HPP_
+
+#include <chrono>
+#include <memory>
+#include <random>
+#include <string>
+
+#include "rclcpp/rclcpp.hpp"
+#include "sensor_msgs/msg/imu.hpp"
+
+namespace imu_msgs
+{
+constexpr char DEFAULT_TOPIC_NAME[] = "imu_chatter";
+}
+
+class ImuTalker : public rclcpp::Node
+{
+public:
+  /// Standard constructor.
+  /**
+    * \param[in] topic_name Topic to publish chatter messages to.
+    * \param[in] publish_period Frequency of publishing chatter messages.
+    **/
+  ImuTalker(
+    const std::string & topic_name = imu_msgs::DEFAULT_TOPIC_NAME,
+    std::chrono::milliseconds publish_period = std::chrono::milliseconds(1000));
+
+  /// Initialize the publisher.
+  void initialize();
+
+  /// Publish a single message.
+  void publish();
+
+private:
+  rclcpp::Publisher<sensor_msgs::msg::Imu>::SharedPtr publisher_ = nullptr;
+
+  const std::string topic_name_;
+  std::chrono::milliseconds publish_period_ = std::chrono::milliseconds(1000);
+  rclcpp::TimerBase::SharedPtr publish_timer_ = nullptr;
+
+  std::random_device random_number_seed_;
+  std::mt19937 random_generator_;
+  std::uniform_real_distribution<> random_distribution_;
+};
+
+class ImuListener : public rclcpp::Node
+{
+public:
+  /// Standard Constructor.
+  /**
+    * \param[in] topic_name Topic to subscribe to.
+    * \param[in] subscription_options SubscriptionOptions to use for the subscription.
+    */
+  ImuListener(
+    const std::string & topic_name = imu_msgs::DEFAULT_TOPIC_NAME,
+    const rclcpp::SubscriptionOptions & subscription_options = rclcpp::SubscriptionOptions());
+
+  /// Initialize the listener node.
+  void initialize();
+
+  /// Instantiate a Subscription to the chatter topic.
+  void start_listening();
+
+private:
+  rclcpp::SubscriptionOptions subscription_options_;
+  rclcpp::Subscription<sensor_msgs::msg::Imu>::SharedPtr subscription_ = nullptr;
+
+  const std::string topic_name_;
+};
+
+#endif  // TOPIC_STATISTICS_DEMO__IMU_TALKER_LISTENER_NODES_HPP_

topic_statistics_demo/include/topic_statistics_demo/string_talker_listener_nodes.hpp

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+// 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.
+
+#ifndef TOPIC_STATISTICS_DEMO__STRING_TALKER_LISTENER_NODES_HPP_
+#define TOPIC_STATISTICS_DEMO__STRING_TALKER_LISTENER_NODES_HPP_
+
+#include <chrono>
+#include <memory>
+#include <string>
+
+#include "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/string.hpp"
+
+namespace string_msgs
+{
+constexpr char DEFAULT_TOPIC_NAME[] = "string_chatter";
+}
+
+class StringTalker : public rclcpp::Node
+{
+public:
+  /// Standard constructor.
+  /**
+    * \param[in] topic_name Topic to publish chatter messages to.
+    * \param[in] publish_period Frequency of publishing chatter messages.
+    **/
+  StringTalker(
+    const std::string & topic_name = string_msgs::DEFAULT_TOPIC_NAME,
+    std::chrono::milliseconds publish_period = std::chrono::milliseconds(1000));
+
+  /// Initialize the publisher.
+  void initialize();
+
+  /// Publish a single message.
+  void publish();
+
+private:
+  rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher_ = nullptr;
+
+  const std::string topic_name_;
+
+  std::chrono::milliseconds publish_period_ = std::chrono::milliseconds(1000);
+  rclcpp::TimerBase::SharedPtr publish_timer_ = nullptr;
+  size_t publish_count_ = 0;
+};
+
+class StringListener : public rclcpp::Node
+{
+public:
+  /// Standard constructor.
+  /**
+    * \param[in] topic_name Topic to subscribe to.
+    * \param[in] subscription_options SubscriptionOptions to use for the subscription.
+    */
+  StringListener(
+    const std::string & topic_name = string_msgs::DEFAULT_TOPIC_NAME,
+    const rclcpp::SubscriptionOptions & subscription_options = rclcpp::SubscriptionOptions());
+
+  /// Initialize the listener node.
+  void initialize();
+
+  /// Instantiate a Subscription to the chatter topic.
+  void start_listening();
+
+private:
+  rclcpp::SubscriptionOptions subscription_options_;
+  rclcpp::Subscription<std_msgs::msg::String>::SharedPtr subscription_ = nullptr;
+
+  const std::string topic_name_;
+};
+
+#endif  // TOPIC_STATISTICS_DEMO__STRING_TALKER_LISTENER_NODES_HPP_

topic_statistics_demo/include/topic_statistics_demo/topic_statistics_listener.hpp

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+// 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.
+
+#ifndef TOPIC_STATISTICS_DEMO__TOPIC_STATISTICS_LISTENER_HPP_
+#define TOPIC_STATISTICS_DEMO__TOPIC_STATISTICS_LISTENER_HPP_
+
+#include <string>
+
+#include "rclcpp/rclcpp.hpp"
+#include "statistics_msgs/msg/metrics_message.hpp"
+
+namespace topic_stats_demo
+{
+constexpr char STATISTICS_TOPIC_NAME[] = "statistics";
+}
+
+class TopicStatisticsListener : public rclcpp::Node
+{
+public:
+  /// Standard Constructor.
+  /**
+    * \param[in] topic_name Topic to which statistics are published.
+    */
+  explicit TopicStatisticsListener(
+    const std::string & topic_name = topic_stats_demo::STATISTICS_TOPIC_NAME);
+
+  /// Initialize the listener node.
+  void initialize();
+
+  /// Return string representation of a MetricsMessage.
+  /**
+    * \param[in] results Statistics heard form the subscribed topic.
+    * \param[out] String representation of the input statistics.
+    */
+  std::string MetricsMessageToString(const statistics_msgs::msg::MetricsMessage & results);
+
+  /// Instantiate a Subscription to the statistics topic.
+  void start_listening();
+
+private:
+  rclcpp::SubscriptionOptions subscription_options_;
+  rclcpp::Subscription<statistics_msgs::msg::MetricsMessage>::SharedPtr subscription_ = nullptr;
+
+  const std::string topic_name_;
+};
+
+#endif  // TOPIC_STATISTICS_DEMO__TOPIC_STATISTICS_LISTENER_HPP_

topic_statistics_demo/package.xml

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+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>topic_statistics_demo</name>
+  <version>0.9.3</version>
+  <description>C++ demo application for topic statistics feature.</description>
+
+  <maintainer email="[email protected]">Amazon ROS Contributions</maintainer>
+
+  <license>Apache License 2.0</license>
+
+  <buildtool_depend>ament_cmake</buildtool_depend>
+
+  <build_depend>rclcpp</build_depend>
+  <build_depend>rcutils</build_depend>
+  <build_depend>sensor_msgs</build_depend>
+  <build_depend>statistics_msgs</build_depend>
+
+  <exec_depend>rclcpp</exec_depend>
+  <exec_depend>rcutils</exec_depend>
+  <exec_depend>sensor_msgs</exec_depend>
+  <exec_depend>statistics_msgs</exec_depend>
+
+  <test_depend>ament_lint_auto</test_depend>
+  <test_depend>ament_lint_common</test_depend>
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>