Set Micro XRCE-DDS RMW on tutorials (#311)

Author: Acuadros95

_docs/tutorials/core/first_application_linux/index.md

@@ -74,12 +74,15 @@ To give micro-ROS access to the ROS 2 dataspace, run the agent:
 ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888
 ```
 
-And then, in another command line, run the micro-ROS node (remember sourcing the ROS 2 and micro-ROS installations):
+And then, in another command line, run the micro-ROS node (remember sourcing the ROS 2 and micro-ROS installations, and setting the RMW Micro XRCE-DDS implementation):
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 source install/local_setup.bash
 
+# Use RMW Micro XRCE-DDS implementation
+export RMW_IMPLEMENTATION=rmw_microxrcedds
+
 # Run a micro-ROS node
 ros2 run micro_ros_demos_rclc ping_pong
 ```
@@ -96,7 +99,7 @@ each:
 ```bash
 cd microros_ws
 
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 source install/local_setup.bash
 
 ros2 run micro_ros_demos_rclc ping_pong

_docs/tutorials/core/zephyr_emulator/index.md

@@ -77,7 +77,7 @@ Finally, in order to run the micro-ROS node inside of the Zephyr RTOS emulator,
 open a new command shell and execute the flash step by means of the flashing command:
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 source install/local_setup.bash
 
 # Flash/run step

_includes/first_application_common/build_system.md

@@ -15,7 +15,7 @@ Once you have a ROS 2 installation in the computer, follow these steps to instal
 
 ```bash
 # Source the ROS 2 installation
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Create a workspace and download the micro-ROS tools
 mkdir microros_ws

_includes/first_application_common/test_app_host.md

@@ -6,7 +6,7 @@ Open a new command line. We are going to listen to the `ping` topic
 with ROS 2 to check whether the micro-ROS Ping Pong node is correctly publishing the expected pings:
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Subscribe to micro-ROS ping topic
 ros2 topic echo /microROS/ping
@@ -35,7 +35,7 @@ So, first of all, let's subscribe with ROS 2 to the `pong` topic from a new shel
 (notice that initially we don't expect to receive any pong, since none has been sent yet):
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Subscribe to micro-ROS pong topic
 ros2 topic echo /microROS/pong
@@ -44,7 +44,7 @@ ros2 topic echo /microROS/pong
 And now, let's publish a `fake_ping` with ROS 2 from yet another command line:
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Send a fake ping
 ros2 topic pub --once /microROS/ping std_msgs/msg/Header '{frame_id: "fake_ping"}'

_includes/first_application_common/test_app_rtos.md

@@ -7,7 +7,7 @@ Open a new command line. We are going to listen to the `ping` topic
 with ROS 2 to check whether the micro-ROS Ping Pong node is correctly publishing the expected pings:
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Subscribe to micro-ROS ping topic
 ros2 topic echo /microROS/ping
@@ -36,7 +36,7 @@ So, first of all, let's subscribe with ROS 2 to the `pong` topic from a new shel
 (notice that initially we don't expect to receive any pong, since none has been sent yet):
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Subscribe to micro-ROS pong topic
 ros2 topic echo /microROS/pong
@@ -45,7 +45,7 @@ ros2 topic echo /microROS/pong
 And now, let's publish a `fake_ping` with ROS 2 from yet another command line:
 
 ```bash
-source /opt/ros/foxy/setup.bash
+source /opt/ros/$ROS_DISTRO/setup.bash
 
 # Send a fake ping
 ros2 topic pub --once /microROS/ping std_msgs/msg/Header '{frame_id: "fake_ping"}'