Everything You Need in a Docker Container
-----------------------------------------

Docker provides a quick and easy way to get up and running with Mynewt.
The newt command line tool and the entire build toolchain is available
in a single docker container. The container is all that's needed to run
your Mynewt based application in the simulator. Enabling USB2 with your
docker installation will allow you to load your application on a
supported device.

Docker is the only supported option if you are working on a Windows
machine. If you are using Mac OS X or Linux, you have the choice of
installing a Docker container of tools and toolchains or installing them
natively. This chapter describes how to set up the Docker image for all
three platforms.

.. contents::
  :local:
  :depth: 2

Install Docker
~~~~~~~~~~~~~~

Install docker for your platform. `Mac OS
X <https://www.docker.com/products/docker-toolbox>`__ /
`Windows <https://www.docker.com/products/docker-toolbox>`__ /
`Linux <https://docs.docker.com/engine/installation/linux/>`__

Mac and Windows
^^^^^^^^^^^^^^^

Mac and Windows require Docker Toolbox to interact with USB devices.
Docker for Mac and Docker for Windows do not support USB. Docker Toolbox
uses VirtualBox and allows you to map USB devices into docker containers
as described below.

Make sure to double click the Docker Quickstart Terminal application if
you're on Mac or Windows.

Linux
^^^^^

The docker daemon listens on a Unix domain socket on Linux. That socket
is owned by root, which means by default you must be root to start a
container. Make sure to follow the optional step of adding yourself to
the docker group so you can start the newt container as yourself.

Pull the Mynewt Container
~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: console

    $ docker pull mynewt/newt:latest

**Note** You can upgrade your container by repeating this command when updates are made available.

Use a ``newt`` wrapper script
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Use the newt wrapper script to invoke newt. Create the following file,
name it ``newt``, make it executable, and put it in your path. This will
allow you to run newt as if it was natively installed. You can now
follow the normal tutorials using the newt wrapper script.

.. code-block:: sh

    #!/bin/bash

    if [ "$1" = "debug" ] || [ "$1" = "run" ]
    then
        ti="-ti"
    fi

    docker run -e NEWT_USER=$(id -u) -e NEWT_GROUP=$(id -g) -e NEWT_HOST=$(uname) $ti --rm --device=/dev/bus/usb --privileged -v $(pwd):/workspace -w /workspace mynewt/newt:latest /newt "$@"

**Note** Remember to point to the correct subdirectory level when
invoking ``newt``. For example, invoke it using ``../newt`` in the
example below.

.. code:: console

    user@~/dockertest$ ls
    myproj  newt
    user@~/dockertest$ cd myproj
    user@~/dockertest/myproj$ ../newt version
    Apache Newt version: 1.1.0

Enable USB2 Support for Mac or Windows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you plan on loading your application on an actual device, do the
steps below.

Install VirtualBox extension pack
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Docker uses a VirtualBox Linux VM to run containers. A free VirtualBox
extension pack is required to enable USB2 support. Download the
`VirtualBox Extension
Pack <https://www.virtualbox.org/wiki/Downloads>`__ version that matches
your VirtualBox installation and double click to install

Enable USB2 and select your device
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

-  The "default" VM created by docker-machine must first be stopped
   before you can enable USB2. You have two options:

   -  Run the command ``docker-machine stop default`` in the terminal
      window or
   -  Use the VirtualBox UI. Right click on ``default`` -> Close ->
      Power Off

-  Enable USB2 using the VirtualBox UI. Select the "default"
   VM->Settings->Ports->USB2 to enable USB2. Add your device to the USB
   Device Filters to make the device visible in the docker container.
   See the image below.

-  Restart the "default" VM. You have two options:

   -  Run ``docker-machine start default`` in the terminal window or
   -  Use the VirtualBox UI. Make sure the "default" machine is
      highlighted. Click the green "Start" button. Select "Headless Start".

.. image:: pics/virtualbox_usb.jpg

**Note**: When working with actual hardware, remember that each board
has an ID. If you swap boards and do not refresh the USB Device Filter
on the VirtualBox UI, the ID might be stale and the Docker instance may
not be able to see the board correctly. For example, you may see an
error message like ``Error: unable to find CMSIS-DAP device`` when you
try to load or run an image on the board. In that case, you need to
click on the USB link in VirtualBox UI, remove the existing USB Device
Filter (e.g. "Atmel Corp. EDBG CMSIS-DAP[0101]") by clicking on the
"Removes selected USB filter" button, and add a new filter by clicking
on the "Adds new USB filter" button.