Unique network flows (#296)

* Demonstrate unique network flows feature Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> * Use new unique network flow option Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> * Modify to match renamed API Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> * Rename files for consistency Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> * Update build configuration Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> * Catch exception on failure to create subscriber Signed-off-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com> Co-authored-by: Ananya Muddukrishna <ananya.x.muddukrishna@ericsson.com>
ros2 · Apr 5, 2021 · c378340 · c378340
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diff --git a/rclcpp/topics/minimal_publisher/CMakeLists.txt b/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_endpoints member_function_with_unique_network_flow_endpoints.cpp)
+ament_target_dependencies(publisher_member_function_with_unique_network_flow_endpoints 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_endpoints
   publisher_not_composable
   DESTINATION lib/${PROJECT_NAME}
 )

diff --git a/rclcpp/topics/minimal_publisher/member_function_with_unique_network_flow_endpoints.cpp b/rclcpp/topics/minimal_publisher/member_function_with_unique_network_flow_endpoints.cpp
@@ -0,0 +1,112 @@
+// 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 MinimalPublisherWithUniqueNetworkFlowEndpoints : public rclcpp::Node
+{
+public:
+  MinimalPublisherWithUniqueNetworkFlowEndpoints()
+  : Node("minimal_publisher_with_unique_network_flow_endpoints"), count_1_(0), count_2_(0)
+  {
+    // Create publisher with unique network flow endpoints
+    // Enable unique network flow endpoints via options
+    auto options_1 = rclcpp::PublisherOptions();
+    options_1.require_unique_network_flow_endpoints =
+      RMW_UNIQUE_NETWORK_FLOW_ENDPOINTS_OPTIONALLY_REQUIRED;
+    publisher_1_ = this->create_publisher<std_msgs::msg::String>("topic_1", 10, options_1);
+    timer_1_ = this->create_wall_timer(
+      500ms, std::bind(&MinimalPublisherWithUniqueNetworkFlowEndpoints::timer_1_callback, this));
+
+    // Create publisher without unique network flow endpoints
+    // Unique network flow endpoints are disabled in default options
+    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(&MinimalPublisherWithUniqueNetworkFlowEndpoints::timer_2_callback, this));
+
+    // Get network flow endpoints
+    auto network_flow_endpoints_1 = publisher_1_->get_network_flow_endpoints();
+    auto network_flow_endpoints_2 = publisher_2_->get_network_flow_endpoints();
+
+    // Print network flow endpoints
+    print_network_flow_endpoints(network_flow_endpoints_1);
+    print_network_flow_endpoints(network_flow_endpoints_2);
+  }
+
+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);
+  }
+  /// Print network flow endpoints in JSON-like format
+  void print_network_flow_endpoints(
+    const std::vector<rclcpp::NetworkFlowEndpoint> & network_flow_endpoints) const
+  {
+    std::ostringstream stream;
+    stream << "{\"networkFlowEndpoints\": [";
+    bool comma_skip = true;
+    for (auto network_flow_endpoint : network_flow_endpoints) {
+      if (comma_skip) {
+        comma_skip = false;
+      } else {
+        stream << ",";
+      }
+      stream << network_flow_endpoint;
+    }
+    stream << "]}";
+    RCLCPP_INFO(
+      this->get_logger(), "%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<MinimalPublisherWithUniqueNetworkFlowEndpoints>());
+  rclcpp::shutdown();
+  return 0;
+}
diff --git a/rclcpp/topics/minimal_subscriber/CMakeLists.txt b/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_endpoints member_function_with_unique_network_flow_endpoints.cpp)
+ament_target_dependencies(subscriber_member_function_with_unique_network_flow_endpoints 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_endpoints
   subscriber_not_composable
   DESTINATION lib/${PROJECT_NAME})
 

diff --git a/rclcpp/topics/minimal_subscriber/member_function_with_unique_network_flow_endpoints.cpp b/rclcpp/topics/minimal_subscriber/member_function_with_unique_network_flow_endpoints.cpp
@@ -0,0 +1,120 @@
+// 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 MinimalSubscriberWithUniqueNetworkFlowEndpoints : public rclcpp::Node
+{
+public:
+  MinimalSubscriberWithUniqueNetworkFlowEndpoints()
+  : Node("minimal_subscriber_with_unique_network_flow_endpoints")
+  {
+    try {
+      // Create subscription with unique network flow endpoints
+      // Enable unique network flow endpoints via options
+      // Since option is strict, expect exception
+      auto options_1 = rclcpp::SubscriptionOptions();
+      options_1.require_unique_network_flow_endpoints =
+        RMW_UNIQUE_NETWORK_FLOW_ENDPOINTS_STRICTLY_REQUIRED;
+
+      subscription_1_ = this->create_subscription<std_msgs::msg::String>(
+        "topic_1", 10, std::bind(
+          &MinimalSubscriberWithUniqueNetworkFlowEndpoints::topic_1_callback, this,
+          _1), options_1);
+
+      // Create subscription without unique network flow endpoints
+      // Unique network flow endpoints are disabled by default
+      auto options_2 = rclcpp::SubscriptionOptions();
+      subscription_2_ = this->create_subscription<std_msgs::msg::String>(
+        "topic_2", 10, std::bind(
+          &MinimalSubscriberWithUniqueNetworkFlowEndpoints::topic_2_callback, this,
+          _1), options_2);
+
+      // Get network flow endpoints
+      auto network_flow_endpoints_1 = subscription_1_->get_network_flow_endpoints();
+      auto network_flow_endpoints_2 = subscription_2_->get_network_flow_endpoints();
+
+      // Check if network flow endpoints are unique
+      for (auto network_flow_endpoint_1 : network_flow_endpoints_1) {
+        for (auto network_flow_endpoint_2 : network_flow_endpoints_2) {
+          if (network_flow_endpoint_1 == network_flow_endpoint_2) {
+            RCLCPP_ERROR(
+              this->get_logger(), "Network flow endpoints across subscriptions are not unique");
+            break;
+          }
+        }
+      }
+
+      // Print network flow endpoints
+      print_network_flow_endpoints(network_flow_endpoints_1);
+      print_network_flow_endpoints(network_flow_endpoints_2);
+    } catch (const rclcpp::exceptions::RCLError & e) {
+      RCLCPP_ERROR(
+        this->get_logger(),
+        "Error: %s",
+        e.what());
+    }
+  }
+
+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());
+  }
+  /// Print network flow endpoints in JSON-like format
+  void print_network_flow_endpoints(
+    const std::vector<rclcpp::NetworkFlowEndpoint> & network_flow_endpoints) const
+  {
+    std::ostringstream stream;
+    stream << "{\"networkFlowEndpoints\": [";
+    bool comma_skip = true;
+    for (auto network_flow_endpoint : network_flow_endpoints) {
+      if (comma_skip) {
+        comma_skip = false;
+      } else {
+        stream << ",";
+      }
+      stream << network_flow_endpoint;
+    }
+    stream << "]}";
+    RCLCPP_INFO(
+      this->get_logger(), "%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<MinimalSubscriberWithUniqueNetworkFlowEndpoints>());
+  rclcpp::shutdown();
+  return 0;
+}