Cheat Sheet
===========
ROS2 Commands
-------------
Workspace & Package Management
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. raw:: html
+--------------------------------------+------------------------------------------------------------------+
| CLI | Command |
+======================================+==================================================================+
| Set up workspace | ``mkdir -p ~/
/src`` |
+--------------------------------------+------------------------------------------------------------------+
| Create Python package | ``ros2 pkg create --build-type ament_python`` |
+--------------------------------------+------------------------------------------------------------------+
| Create C++ package | ``ros2 pkg create --build-type ament_cmake`` |
+--------------------------------------+-----------------+------------------------------------------------+
| Build all packages | ``colcon build``| Should be run in: **~/** |
+--------------------------------------+-----------------+------------------------------------------------+
| Build specific package | ``colcon build --packages-select `` |
+--------------------------------------+------------------------------------------------------------------+
| Build package with symlink install | ``colcon build --packages-select --symlink-install`` |
+--------------------------------------+------------------------------------------------------------------+
| Source workspace | ``source ~//install/setup.bash`` |
+--------------------------------------+------------------------------------------------------------------+
.. raw:: html
+--------------------------------------+--------------------------------------------------------------+
| CLI | Command |
+======================================+==============================================================+
| Run a node | ``ros2 run
`` |
+--------------------------------------+--------------------------------------------------------------+
| Launch nodes and configurations | ``ros2 launch `` |
+--------------------------------------+--------------------------------------------------------------+
.. raw:: html
+-----------------------------------------+-----------------------------------------------------------------+
| CLI | Command |
+=========================================+=================================================================+
| List all nodes | ``ros2 node list`` |
+-----------------------------------------+-----------------------------------------------------------------+
| Get details on a node | ``ros2 node info `` |
+-----------------------------------------+-----------------------------------------------------------------+
| List all topics + message type | ``ros2 topic list -t`` |
+-----------------------------------------+-----------------------------------------------------------------+
| Get details on a message type | ``ros2 interface show `` |
+-----------------------------------------+-----------------------------------------------------------------+
| Display messages published to a topic | ``ros2 topic echo `` |
+-----------------------------------------+-----------------------------------------------------------------+
| List all services + service type | ``ros2 service list -t`` |
+-----------------------------------------+-----------------------------------------------------------------+
| Get details on a service type | ``ros2 interface show `` |
+-----------------------------------------+-----------------------------------------------------------------+
.. raw:: html
Tools & Utilities
~~~~~~~~~~~~~~~~~
.. raw:: html
+-----------------------------------------+-----------------------------------------------------------------+
| CLI | Command |
+=========================================+=================================================================+
| Launch the RViz visualization tool | ``rviz2`` |
+-----------------------------------------+-----------------------------------------------------------------+
| Show the ROS2 node graph in rqt | ``rqt_graph`` |
+-----------------------------------------+-----------------------------------------------------------------+
| Start the Gazebo simulation environment | ``gazebo`` |
+-----------------------------------------+-----------------------------------------------------------------+
.. raw:: html
ROS2 Basic Structures
---------------------
Minimal Node
~~~~~~~~~~~~
.. code-block:: python
import rclpy
from rclpy.node import Node
class MinimalNode(Node):
def __init__(self):
super().__init__("node_name")
self.get_logger().info("Minimal Node has been started")
def main(args=None):
rclpy.init(args=args)
minimal_node = MinimalNode()
rclpy.spin(minimal_node)
minimal_node.destroy_node()
rclpy.shutdown()
if __name__ == "__main__":
main()
Minimal Publisher
~~~~~~~~~~~~~~~~~
.. code-block:: python
import rclpy
from rclpy.node import Node
from std_msgs.msg import String
class MinimalPublisher(Node):
def __init__(self):
super().__init__('minimal_publisher')
self.publisher_ = self.create_publisher(String, 'topic', 10)
timer_period = 0.5 # seconds
self.timer = self.create_timer(timer_period, self.timer_callback)
self.i = 0
def timer_callback(self):
msg = String()
msg.data = 'Hello World: %d' % self.i
self.publisher_.publish(msg)
self.get_logger().info('Publishing: "%s"' % msg.data)
self.i += 1
def main(args=None):
rclpy.init(args=args)
minimal_publisher = MinimalPublisher()
rclpy.spin(minimal_publisher)
minimal_publisher.destroy_node()
rclpy.shutdown()
if __name__ == '__main__':
main()
Minimal Subscriber
~~~~~~~~~~~~~~~~~~
.. code-block:: python
import rclpy
from rclpy.node import Node
from std_msgs.msg import String
class MinimalSubscriber(Node):
def __init__(self):
super().__init__('minimal_subscriber')
self.subscription = self.create_subscription(String,'topic',
self.listener_callback, 10)
self.subscription # prevent unused variable warning
def listener_callback(self, msg):
self.get_logger().info('I heard: "%s"' % msg.data)
def main(args=None):
rclpy.init(args=args)
minimal_subscriber = MinimalSubscriber()
rclpy.spin(minimal_subscriber)
minimal_subscriber.destroy_node()
rclpy.shutdown()
if __name__ == '__main__':
main()
Minimal Server
~~~~~~~~~~~~~~
.. code-block:: python
import rclpy
from rclpy.node import Node
from example_interfaces.srv import AddTwoInts
class MinimalServer(Node):
def __init__(self):
super().__init__('minimal_server')
self.srv = self.create_service(AddTwoInts, 'add_two_ints', self.add_two_ints_callback)
def add_two_ints_callback(self, request, response):
response.sum = request.a + request.b
self.get_logger().info('Incoming request\na: %d b: %d' % (request.a, request.b))
return response
def main():
rclpy.init()
minimal_server = MinimalServer()
rclpy.spin(minimal_server)
minimal_server.destroy_node()
rclpy.shutdown()
if __name__ == '__main__':
main()
Minimal Client
~~~~~~~~~~~~~~
.. code-block:: python
import rclpy
from rclpy.node import Node
from functools import partial
from example_interfaces.srv import AddTwoInts
class MinimalClient(Node):
def __init__(self):
super().__init__("minimal_client")
self.call_add_two_ints_server(6, 7)
def call_add_two_ints_server(self, a, b):
client = self.create_client(AddTwoInts, "add_two_ints")
while not client.wait_for_service(1.0):
self.get_logger().warn("Waiting for Server Add Two Ints...")
request = AddTwoInts.Request()
request.a = a
request.b = b
future = client.call_async(request)
future.add_done_callback(partial(self.callback_call_add_two_ints, a=a, b=b))
def callback_call_add_two_ints(self, future, a, b):
try:
response = future.result()
self.get_logger().info(str(a) + " + " + str(b) + " = " + str(response.sum))
except Exception as e:
self.get_logger().error("Service call failed %r" % (e,))
def main(args=None):
rclpy.init(args=args)
minimal_client = MinimalClient()
rclpy.spin(minimal_client)
minimal_client.destroy_node()
rclpy.shutdown()
if __name__ == "__main__":
main()