# ROS 2
# Extension
[Following the documentation here](https://github.com/rshu-bd/spot_ros2/tree/rshu-bd/spot_core_extension/spot_coreio_extension)
## [Build The Extension](https://github.com/rshu-bd/spot_ros2/tree/rshu-bd/spot_core_extension/spot_coreio_extension#build-the-extension)
This directory contains a script create\_extension.sh that can be used to create an l4t-based Spot Extension for this example. This will create a file spot\_detect\_and\_follow.spx, which can be uploaded to the CORE I/O. The extension requires that the payload be authorized on the robot admin console to run.
If building on a host system architecture that is not `ARM64` based run the following before continuing.
```bash
sudo apt-get install qemu binfmt-support qemu-user-static
```
Installing and running qemu will allow us to build ARM binaries on an x86 machine without needing a cross compiler, see [Build Docker Images Documentation](https://dev.bostondynamics.com/docs/payload/docker_containers#build-docker-images) for more details.
This directory contains a script `create_extension.sh` that can be used to build a `ARM64` docker image and package all the files into an Extension. From the `ros2_driver` directory run the script
```bash
./create_extension.sh
```
This will create the `spot_ros2_driver.spx` extension file that you can upload to the CORE I/O or Scout platform. The script was tested on Ubuntu 22.04 with x86 architecture.
---
Before you install and run the `spot_ros2_driver.spx` you need to configure the port range used by a connection in the CORE I/O to be within the allowable port range.
### [Limit the ports used by a connection in the CORE I/O](https://github.com/rshu-bd/spot_ros2/tree/rshu-bd/spot_core_extension/spot_coreio_extension#limit-the-ports-used-by-a-connection-in-the-core-io)
SSH into the CORE I/O from the robot’s WiFi
```bash
ssh -p 20022 spot@192.168.80.3
```
Make a copy of the default port range (not currently working with our CORE io)
```bash
cat /proc/sys/net/ipv4/ip_local_port_range > /proc/sys/net/ipv4/ip_local_port_range.bak
```
The default configuration of the ip\_local\_port\_range
```bash
32768 60999
```
Limit the ports a networking connection can use to those reachable through the CORE I/O's firewall
```bash
echo "21000 22000" | sudo tee /proc/sys/net/ipv4/ip_local_port_range
```
This will force all connections from the CORE I/O to be on the port range 21000 - 22000.
# ROS2 Container to container communication
### To-Do
- Determine why multicast send and receive are not working on our network.
- More testing with other ROS2 packages.
### Setup
In this setup, we have two containers:
1. The Boston Dynamics ROS2 [Spot ROS2](https://github.com/rshu-bd/spot_ros2/tree/rshu-bd/spot_core_extension) container in the an extension file build using [these instructions](https://github.com/rshu-bd/spot_ros2/tree/rshu-bd/spot_core_extension/spot_coreio_extension).
2. Our container built for Spot.
### Network
### Container Configuration
##### Extension Container
1. You need to ssh into the CORE I/O via the default IP of 192.168.80.3 or 192.168.50.3 if you are connected directly to the CORE I/O.
- ```bash
ssh 192.168.80.3
```
2. You will need to lock down the CORE I/O to a specific port range. This is so that the containers choose ports that are open.
- ```bash
echo "21000 22000" | sudo tee /proc/sys/net/ipv4/ip_local_port_range
```
3. **You must restart the containers/extension after changing the ports on the CORE I/O**
4. You need to find the container id of your ROS2 installation.
- ```bash
sudo docker container ls
```
1. Once you have your container id you will need to open up into the container.
- ```bash
sudo docker exec -it 8966bcde886b /bin/bash # replace "8966bcde886b" with your container id
```
2. Once inside the container.
- The Extension container was setup with the following commands to test:
```bash
ping 192.168.50.20 # Ping test the dev computer.
export ROS_DISCOVERY_SERVER=192.168.50.5:21000 # This was changed from the BD default of 192.168.80.3 because we are using our own WiFi setup that bypasses Spot's internal network.
source ./install/setup.bash # Source workspace
source /opt/ros/humble/setup.bash # Source ROS2
ros2 run demo_nodes_cpp listener --ros-args --remap __node:=listener_discovery_server
```
##### Dev Container
The Dev container was setup with the following commands to test:
```bash
ping 192.168.50.5 # Ping test the CORE I/O.
export ROS_DISCOVERY_SERVER=192.168.50.5:21000 # This was changed from the BD default of 192.168.80.3 because we are using our own WiFi setup that bypasses Spot's internal network.
source ./install/setup.bash # Source workspace
source /opt/ros/humble/setup.bash # Source ROS2
ros2 run demo_nodes_cpp talker --ros-args --remap __node:=talker_discovery_server
```
