deviceconnectfs

A 9P synthetic filesystem that projects a Device Connect-style device/function model into a navigable namespace, served with go9p.

This was originally an example under p/srv/examples/deviceconnect/ in go9p and is now maintained as a standalone project so it can grow independently of the core 9P library.

See [DESIGN.md](./DESIGN.md) for the full design notes (filesystem shape, semantics, clone/ctl call pattern, events, and future session ideas).

Filesystem shape (current)

/
  devices/
    discover
    by-id/
      <device-id>/
        meta
        status
        events/{replay,stream}
        values/<value-name>/value
        values/<value-name>/events/{replay,stream}
        functions/<function-name>/
          about
          schema
          clone
          <call-id>/
            ctl
            data
            error
            stream

Function invocation uses the Plan 9 clone pattern: read clone to allocate a per-call directory, write request bytes to data, write call to ctl, then read the response from data. Closing the last open ctl reference garbage collects the call directory.

Run

go run ./cmd/go9p-deviceconnectfs -addr 127.0.0.1:5642

Flags:

• -addr <host:port>: listen address (default :5642)
• -d: print 9P debug messages

From another terminal you can drive it with any go9p client, for example the session helper from your go9p checkout:

go run /Users/erivan01/src/v9fs/go9p/cmd/go9p-session -net tcp -addr 127.0.0.1:5642

Example session commands:

cat /devices/discover
cat /devices/by-id/robot-001/meta
cat /devices/by-id/robot-001/status
read /devices/by-id/robot-001/functions/echo/clone
write /devices/by-id/robot-001/functions/echo/<id>/data hello
write /devices/by-id/robot-001/functions/echo/<id>/ctl call
cat /devices/by-id/robot-001/functions/echo/<id>/data

Mount with the Linux kernel 9p client

sudo mount -t 9p -o trans=tcp,port=5642,version=9p2000.u,uname=$USER,access=any 127.0.0.1 /mnt/deviceconnectfs
ls /mnt/deviceconnectfs/devices

access=any keeps kernel-client smoke tests focused on filesystem semantics rather than synthetic Unix ownership details.

Tests

go test ./...

The userspace tests exercise discovery, values, events, function invocation, stream behavior, error files, and ctl-close garbage collection through an in-process go9p client.

Kernel 9p e2e

The repository includes a QEMU-based smoke path matching the v9fs/test style used by go9p-netfs:

docker run --rm --privileged --platform linux/arm64   -v "$PWD:/opt/v9fs/deviceconnectfs"   -w /opt/v9fs/deviceconnectfs   -e V9FS_TEST_KERNEL_TAG=kernel-main   ghcr.io/v9fs/docker:v2.0.0   bash /opt/v9fs/deviceconnectfs/scripts/v9fs/ci-e2e-deviceconnectfs.sh

Status

This module currently builds against the rework branch of github.com/ericvh/go9p (pinned via a replace directive in go.mod) until the changes there are merged upstream into github.com/lionkov/go9p.