Complete parrot example.

CMakeLists.txt

@@ -9,19 +9,29 @@ endif()
 find_package(ament_cmake REQUIRED)
 find_package(rclcpp REQUIRED)
 find_package(std_msgs REQUIRED)
+find_package(fmt REQUIRED)
 
 add_executable(j7s-publisher src/j7s-publisher.cpp)
 target_include_directories(j7s-publisher PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:include>)
-target_compile_features(j7s-publisher PUBLIC c_std_99 cxx_std_17)  # Require C99 and C++17
+target_compile_features(j7s-publisher PUBLIC c_std_99 cxx_std_17)
+target_link_libraries(j7s-publisher fmt::fmt)
 ament_target_dependencies(j7s-publisher rclcpp std_msgs)
 
+add_executable(j7s-parrot src/j7s-parrot.cpp)
+target_include_directories(j7s-parrot PUBLIC
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  $<INSTALL_INTERFACE:include>)
+target_compile_features(j7s-parrot PUBLIC c_std_99 cxx_std_17)
+target_link_libraries(j7s-parrot fmt::fmt)
+ament_target_dependencies(j7s-parrot rclcpp std_msgs)
+
 install(DIRECTORY
   launch
   DESTINATION share/${PROJECT_NAME}/
 )
-install(TARGETS j7s-publisher
+install(TARGETS j7s-publisher j7s-parrot
   DESTINATION lib/${PROJECT_NAME})
 
 ament_package()

include/j7s-simple/j7s-parrot.hpp

@@ -0,0 +1,30 @@
+// Copyright 2023 James Pace
+//
+// 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.
+#pragma once
+
+#include <string>
+
+#include "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/string.hpp"
+
+class J7sParrot : public rclcpp::Node
+{
+public:
+    J7sParrot();
+
+private:
+    rclcpp::Publisher<std_msgs::msg::String>::SharedPtr m_publisher;
+    rclcpp::Subscription<std_msgs::msg::String>::SharedPtr m_subscription;
+    const std::string m_name;
+};

include/j7s-simple/j7s-publisher.hpp

@@ -13,6 +13,8 @@
 // limitations under the License.
 #pragma once
 
+#include <string>
+
 #include "rclcpp/rclcpp.hpp"
 #include "std_msgs/msg/string.hpp"
 
@@ -20,7 +22,10 @@ class J7sPublisher: public rclcpp::Node
 {
 public:
     J7sPublisher();
+
 private:
     rclcpp::TimerBase::SharedPtr m_timer;
     rclcpp::Publisher<std_msgs::msg::String>::SharedPtr m_publisher;
+    const std::string m_message;
+    unsigned int m_count;
 };

launch/j7s_publisher_launch.py

@@ -2,9 +2,26 @@ import launch
 import launch_ros.actions
 
 def generate_launch_description():
-    return launch.LaunchDescription([
-        launch_ros.actions.Node(
+    publisher_node = launch_ros.actions.Node(
             package='j7s-simple',
             executable='j7s-publisher',
-            name='j7s_publisher')
+            name='j7s_publisher',
+            parameters=[{
+                "message":"Hello"
+            }]
+        )
+    parrot_node = launch_ros.actions.Node(
+            package='j7s-simple',
+            executable='j7s-parrot',
+            name='j7s_parrot_1',
+            parameters=[{
+                "name":"Polly"
+            }],
+            remappings=[
+                ("~/parrot_in", "/j7s_publisher/main_out")
+            ]
+        )
+    return launch.LaunchDescription([
+        publisher_node,
+        parrot_node
      ])

package.xml

@@ -8,6 +8,7 @@
   <license>Apache-2.0</license>
 
   <buildtool_depend>ament_cmake</buildtool_depend>
+  <depend>fmt</depend>
   <depend>std_msgs</depend>
   <depend>rclcpp</depend>
 

src/j7s-parrot.cpp

@@ -0,0 +1,39 @@
+// Copyright 2023 James Pace
+//
+// 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 <fmt/core.h>
+
+#include <chrono>
+#include <j7s-simple/j7s-parrot.hpp>
+using namespace std::chrono_literals;
+
+J7sParrot::J7sParrot() : Node("j7s_parrot"), m_name{declare_parameter<std::string>("name")}
+{
+    m_publisher = this->create_publisher<std_msgs::msg::String>("~/parrot_out", 1);
+    m_subscription = this->create_subscription<std_msgs::msg::String>(
+        "~/parrot_in", 1,
+        [this](const std_msgs::msg::String & msg)
+        {
+            std_msgs::msg::String new_msg;
+            new_msg.data = fmt::format("{} says: {}", m_name, msg.data);
+            m_publisher->publish(new_msg);
+        });
+}
+
+int main(int argc, char ** argv)
+{
+    rclcpp::init(argc, argv);
+    rclcpp::spin(std::make_shared<J7sParrot>());
+    rclcpp::shutdown();
+    return 0;
+}

src/j7s-publisher.cpp

@@ -11,19 +11,21 @@
 // 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 <j7s-simple/j7s-publisher.hpp>
+#include <fmt/core.h>
 
 #include <chrono>
+#include <j7s-simple/j7s-publisher.hpp>
 using namespace std::chrono_literals;
 
-
 J7sPublisher::J7sPublisher() :
-    Node("j7s_publisher")
+    Node("j7s_publisher"), m_message{declare_parameter<std::string>("message")}, m_count{0}
+{
+    m_publisher = this->create_publisher<std_msgs::msg::String>("~/main_out", 1);
+    const auto callback = [this]()
     {
-    m_publisher = this->create_publisher<std_msgs::msg::String>("j7s_hello", 1);
-    const auto callback = [this]() {
         std_msgs::msg::String msg;
-        msg.data = "Hello from j7s!";
+        msg.data = fmt::format("{} count: {}", m_message, m_count);
+        m_count++;
         m_publisher->publish(msg);
     };
     m_timer = this->create_wall_timer(500ms, callback);