Demonstrate unique network flows feature

Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com>

rclcpp/topics/minimal_publisher/CMakeLists.txt

@@ -20,12 +20,16 @@ ament_target_dependencies(publisher_lambda rclcpp std_msgs)
 add_executable(publisher_member_function member_function.cpp)
 ament_target_dependencies(publisher_member_function rclcpp std_msgs)
 
+add_executable(publisher_member_function_with_unique_network_flow member_function_with_unique_network_flow.cpp)
+ament_target_dependencies(publisher_member_function_with_unique_network_flow rclcpp std_msgs)
+
 add_executable(publisher_not_composable not_composable.cpp)
 ament_target_dependencies(publisher_not_composable rclcpp std_msgs)
 
 install(TARGETS
   publisher_lambda
   publisher_member_function
+  publisher_member_function_with_unique_network_flow
   publisher_not_composable
   DESTINATION lib/${PROJECT_NAME}
 )

rclcpp/topics/minimal_publisher/member_function_with_unique_network_flow.cpp

@@ -0,0 +1,121 @@
+// Copyright 2020 Ericsson AB
+//
+// 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 <functional>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp/publisher_options.hpp"
+#include "std_msgs/msg/string.hpp"
+
+using namespace std::chrono_literals;
+
+class MinimalPublisherWithUniqueNetworkFlow : public rclcpp::Node
+{
+public:
+  MinimalPublisherWithUniqueNetworkFlow()
+  : Node("minimal_publisher_with_unique_network_flow"), count_1_(0), count_2_(0)
+  {
+    // Enable unique network flow via options
+    auto options_1 = rclcpp::PublisherOptions();
+    options_1.unique_network_flow = true;
+    publisher_1_ = this->create_publisher<std_msgs::msg::String>("topic_1", 10, options_1);
+    timer_1_ = this->create_wall_timer(
+      500ms, std::bind(&MinimalPublisherWithUniqueNetworkFlow::timer_1_callback, this));
+
+    // Unique network flow is disabled by default
+    auto options_2 = rclcpp::PublisherOptions();
+    publisher_2_ = this->create_publisher<std_msgs::msg::String>("topic_2", 10);
+    timer_2_ = this->create_wall_timer(
+      1000ms, std::bind(&MinimalPublisherWithUniqueNetworkFlow::timer_2_callback, this));
+
+    // Print network flows and check for uniqueness
+    auto network_flows_1 = publisher_1_->get_network_flow();
+    auto network_flows_2 = publisher_2_->get_network_flow();
+    print_network_flows(network_flows_1);
+    print_network_flows(network_flows_2);
+    if (!are_network_flows_unique(network_flows_1, network_flows_2)) {
+      RCLCPP_ERROR(this->get_logger(), "Network flows across publishers are not unique");
+    }
+  }
+
+private:
+  void timer_1_callback()
+  {
+    auto message = std_msgs::msg::String();
+    message.data = "Hello, world! " + std::to_string(count_1_++);
+
+    RCLCPP_INFO(
+      this->get_logger(), "Publishing: '%s'", message.data.c_str());
+    publisher_1_->publish(message);
+  }
+  void timer_2_callback()
+  {
+    auto message = std_msgs::msg::String();
+    message.data = "Hej, världen! " + std::to_string(count_2_++);
+
+    RCLCPP_INFO(
+      this->get_logger(), "Publishing: '%s'", message.data.c_str());
+    publisher_2_->publish(message);
+  }
+  /// Compare network flows
+  /*
+   * Compare two network flows
+   * \return false if network flows are not unique true otherwise
+   */
+  bool are_network_flows_unique(
+    const std::vector<rclcpp::NetworkFlow> & network_flows_1,
+    const std::vector<rclcpp::NetworkFlow> & network_flows_2) const
+  {
+    if (network_flows_1.size() > 0 && network_flows_2.size() > 0) {
+      for (auto network_flow_1 : network_flows_1) {
+        for (auto network_flow_2 : network_flows_2) {
+          if (network_flow_1 == network_flow_2) {
+            return false;
+          }
+        }
+      }
+    }
+    return true;
+  }
+  /// Print network flows
+  void print_network_flows(const std::vector<rclcpp::NetworkFlow> & network_flows) const
+  {
+    std::ostringstream stream;
+    for (auto network_flow : network_flows) {
+      stream << network_flow << ", ";
+    }
+    RCLCPP_INFO(
+      this->get_logger(), "Publisher created with network flows: '%s'",
+      stream.str().c_str());
+  }
+  rclcpp::TimerBase::SharedPtr timer_1_;
+  rclcpp::TimerBase::SharedPtr timer_2_;
+  rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher_1_;
+  rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher_2_;
+  size_t count_1_;
+  size_t count_2_;
+};
+
+int main(int argc, char * argv[])
+{
+  rclcpp::init(argc, argv);
+  rclcpp::spin(std::make_shared<MinimalPublisherWithUniqueNetworkFlow>());
+  rclcpp::shutdown();
+  return 0;
+}

rclcpp/topics/minimal_subscriber/CMakeLists.txt

@@ -23,13 +23,17 @@ 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_member_function_with_unique_network_flow member_function_with_unique_network_flow.cpp)
+ament_target_dependencies(subscriber_member_function_with_unique_network_flow 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_member_function_with_unique_network_flow
   subscriber_not_composable
   DESTINATION lib/${PROJECT_NAME})
 

rclcpp/topics/minimal_subscriber/member_function_with_unique_network_flow.cpp

@@ -0,0 +1,110 @@
+// Copyright 2020 Ericsson AB
+//
+// 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 <functional>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp/subscription_options.hpp"
+#include "std_msgs/msg/string.hpp"
+
+using std::placeholders::_1;
+
+class MinimalSubscriberWithUniqueNetworkFlow : public rclcpp::Node
+{
+public:
+  MinimalSubscriberWithUniqueNetworkFlow()
+  : Node("minimal_subscriber_with_unique_network_flow")
+  {
+    // Enable unique network flow via options
+    auto options_1 = rclcpp::SubscriptionOptions();
+    options_1.unique_network_flow = true;
+
+    subscription_1_ = this->create_subscription<std_msgs::msg::String>(
+      "topic_1", 10, std::bind(
+        &MinimalSubscriberWithUniqueNetworkFlow::topic_1_callback, this,
+        _1), options_1);
+
+    // Unique network flow is disabled by default
+    auto options_2 = rclcpp::SubscriptionOptions();
+    subscription_2_ = this->create_subscription<std_msgs::msg::String>(
+      "topic_2", 10, std::bind(
+        &MinimalSubscriberWithUniqueNetworkFlow::topic_2_callback, this,
+        _1), options_2);
+
+    // Print network flows and check for uniqueness
+    auto network_flows_1 = subscription_1_->get_network_flow();
+    auto network_flows_2 = subscription_2_->get_network_flow();
+    print_network_flows(network_flows_1);
+    print_network_flows(network_flows_2);
+    if (!are_network_flows_unique(network_flows_1, network_flows_2)) {
+      RCLCPP_ERROR(this->get_logger(), "Network flows across subscriptions are not unique");
+    }
+  }
+
+private:
+  void topic_1_callback(const std_msgs::msg::String::SharedPtr msg) const
+  {
+    RCLCPP_INFO(this->get_logger(), "Topic 1 news: '%s'", msg->data.c_str());
+  }
+  void topic_2_callback(const std_msgs::msg::String::SharedPtr msg) const
+  {
+    RCLCPP_INFO(this->get_logger(), "Topic 2 news: '%s'", msg->data.c_str());
+  }
+  /// Compare network flows
+  /*
+   * Compare two network flows
+   * \return false if network flows are not unique true otherwise
+   */
+  bool are_network_flows_unique(
+    const std::vector<rclcpp::NetworkFlow> & network_flows_1,
+    const std::vector<rclcpp::NetworkFlow> & network_flows_2) const
+  {
+    if (network_flows_1.size() > 0 && network_flows_2.size() > 0) {
+      for (auto network_flow_1 : network_flows_1) {
+        for (auto network_flow_2 : network_flows_2) {
+          if (network_flow_1 == network_flow_2) {
+            return false;
+          }
+        }
+      }
+    }
+    return true;
+  }
+  /// Print network flows
+  void print_network_flows(const std::vector<rclcpp::NetworkFlow> & network_flows) const
+  {
+    std::ostringstream stream;
+    for (auto network_flow : network_flows) {
+      stream << network_flow << ", ";
+    }
+    RCLCPP_INFO(
+      this->get_logger(), "Subscription created with network flows: '%s'",
+      stream.str().c_str());
+  }
+  rclcpp::Subscription<std_msgs::msg::String>::SharedPtr subscription_1_;
+  rclcpp::Subscription<std_msgs::msg::String>::SharedPtr subscription_2_;
+};
+
+int main(int argc, char * argv[])
+{
+  rclcpp::init(argc, argv);
+  rclcpp::spin(std::make_shared<MinimalSubscriberWithUniqueNetworkFlow>());
+  rclcpp::shutdown();
+  return 0;
+}