First commit of a simple package that can be used for demonstration.

CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.8)
+project(j7s-simple)
+
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+# find dependencies
+find_package(ament_cmake REQUIRED)
+find_package(rclcpp REQUIRED)
+find_package(std_msgs REQUIRED)
+
+add_executable(j7s-publisher src/j7s-publisher.cpp)
+target_include_directories(j7s-publisher PUBLIC
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  $<INSTALL_INTERFACE:include>)
+target_compile_features(j7s-publisher PUBLIC c_std_99 cxx_std_17)  # Require C99 and C++17
+ament_target_dependencies(j7s-publisher rclcpp std_msgs)
+
+install(DIRECTORY
+  launch
+  DESTINATION share/${PROJECT_NAME}/
+)
+install(TARGETS j7s-publisher
+  DESTINATION lib/${PROJECT_NAME})
+
+ament_package()

include/j7s-simple/j7s-publisher.hpp

@@ -0,0 +1,26 @@
+// 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 "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/string.hpp"
+
+class J7sPublisher: public rclcpp::Node
+{
+public:
+    J7sPublisher();
+private:
+  rclcpp::TimerBase::SharedPtr m_timer;
+  rclcpp::Publisher<std_msgs::msg::String>::SharedPtr m_publisher;
+};

launch/j7s_publisher_launch.py

@@ -0,0 +1,10 @@
+import launch
+import launch_ros.actions
+
+def generate_launch_description():
+    return launch.LaunchDescription([
+        launch_ros.actions.Node(
+            package='j7s-simple',
+            executable='j7s-publisher',
+            name='j7s_publisher')
+  ])

package.xml

@@ -0,0 +1,17 @@
+<?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>j7s-simple</name>
+  <version>0.0.0</version>
+  <description>A set of simple nodes for testing things which package ros2.</description>
+  <maintainer email="jpace121@gmail.com">James Pace</maintainer>
+  <license>Apache-2.0</license>
+
+  <buildtool_depend>ament_cmake</buildtool_depend>
+  <depend>std_msgs</depend>
+  <depend>rclcpp</depend>
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>

src/j7s-publisher.cpp

@@ -0,0 +1,38 @@
+// 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 <j7s-simple/j7s-publisher.hpp>
+
+#include <chrono>
+using namespace std::chrono_literals;
+
+
+J7sPublisher::J7sPublisher():
+    Node("j7s_publisher")
+{
+    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!";
+        m_publisher->publish(msg);
+    };
+    m_timer = this->create_wall_timer(500ms, callback);
+}
+
+int main(int argc, char ** argv)
+{
+    rclcpp::init(argc, argv);
+    rclcpp::spin(std::make_shared<J7sPublisher>());
+    rclcpp::shutdown();
+    return 0;
+}