Exposing a serial USB device to a container

Question

What is the best way to expose a USB device (/dev/cu.usbserial) to a running Docker container? Is it possible to alias the device to a different name within the container similar to how port mapping works? I am trying to read and write to the serial device (flash firmware) from the container since I have all the tools within the container. I have outlined everything that I have tried so far below.

Trial 1: Using --device

Using the --device option, I receive the error: docker: Error response from daemon: error gathering device information while adding custom device "/dev/cu.usbserial": no such file or directory.

Trial 2: Using --mount & --volume

After adding the /dev path to File Sharing under preferences, I tried the following command:

docker run -it --rm --volume $(pwd):/home/app/ --volume /dev/cu.usbserial:/dev/cu.usbserial --entrypoint "/bin/bash" container:tag

But this command actually just hangs forever. And using the --mount analog below:

docker run -it --rm --volume $(pwd):/home/app/ --mount type=bind,source=/dev/cu.usbserial,target=/dev/cu.usbserial --entrypoint "/bin/bash" container:tag

I receive the following error: Error response from daemon: invalid mount config for type "bind": bind source path does not exist: /dev/cu.usbserial.

Trial 3: Using symlink

I also tried to symlink the device to the directory that I attach to the container, but the container is not able to follow the link.

Edit (29/6/2020)

As @Peaceful James points out, if your host machine runs OSX, there is no current solution to this problem. The issue is being tracked here.

Answer 1

Try running your docker container in privileged mode:

sudo docker run -it --rm --volume $(pwd):/home/app/ --privileged --entrypoint "/bin/bash" container:tag

See here for details: https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities

NB: this won't work on "Docker for Mac". See here: https://github.com/docker/for-mac/issues/900