Modifying Pupper code
===============================================

Source code
----------------

All of the software running on the Pi is available here: `pupperv3-monorepo <https://github.com/Nate711/pupperv3-monorepo/tree/main>`_.

On the robot, the pupperv3-monorepo code is located at ``~/pupperv3-monorepo``.

The ROS2 workspace is located at ``~/pupperv3-monorepo/ros2_ws``.

Editing code on the robot
--------------------------------

Steps
-------

#.  SSH to Pupper with::

        ssh pi@pupper.local
    
    If you want to use Foxglove for visualization instead run::
    
        ssh -LA 8765:localhost:8765 pi@pupper.local

    Troubleshooting [#ssh_troubleshooting]_ 

    Enable SSH without password (super convenient!) [#ssh_without_password]_

#. Disable the stack from running on boot (one-time step)::

    sudo systemctl disable robot

#. Set correct permissions (one-time step)::

    sudo chown -R pi /home/pi

#. Modify code (see below for examples)
#. Build code::

    cd ~/pupperv3-monorepo/ros2_ws
    ./build.sh

#. Launch stack::

    ros2 launch neural_controller launch.py


Examples
----------

Train a new RL policy
^^^^^^^^^^^^^^^^^^^^^^^^^^

#. Train a different policy using our colab `here <https://colab.research.google.com/drive/1o3ZVKow29meruRqIj_JzyIhUn9Qam-3T#scrollTo=dctacKGKufq9>`_.
#. Download the resulting .json policy file from the Weights and Biases run generated by the colab and put it in ``neural_controller/launch``
#. Update the ``model_path`` field inside the config file located at ``neural_controller/launch/config.yaml`` to point to the new policy file.
#. Build the code with ``./build.sh``.
#. Simulate your code with ``ros2 launch neural_controller launch.py sim:=True``. A Mujoco simulation window should pop up on the screen or attached monitor.
#. Run the code on the physical hardware with ``ros2 launch neural_controller launch.py``.

Add a new controller to control pupper movement
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

#. Make a new ROS2 package in ``~/pupperv3-monorepo/ros2_ws/src``.
#. Write a node that publishes `Twist <http://docs.ros.org/en/noetic/api/geometry_msgs/html/msg/Twist.html>`_ messages to the ``/cmd_vel`` topic.
#. Update the ``neural_controller/launch/launch.py`` file to include your new node and possibly disable the joystick twist publisher if the messages would conflict.
#. Build the code with ``./build.sh``.
#. Simulate your code with ``ros2 launch neural_controller launch.py sim:=True``. A Mujoco simulation window should pop up on the screen or attached monitor.
#. Run the code on the physical hardware with ``ros2 launch neural_controller launch.py``.

.. rubric:: Footnotes

..  [#ssh_troubleshooting] 
   
    If you get an error saying there's already an entry for pupper.local with a different public key in your known_hosts file, run the following command to remove the entry ``ssh-keygen -R pupper.local``

..  [#ssh_without_password] 

    You can SSH into Pupper without a password by following these steps. First `generate a SSH key <https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent>`_. 
    Then copy your computer's SSH key to Pupper ``ssh-copy-id -i ~/.ssh/id_ed25519.pub pi@pupper.local``