# Optional WarmteLink serial overlay. Use only together with docker-compose.yml:
#   WARMTELINK_DEVICE_PATH=/dev/serial/by-id/<stable-by-id-name> \
#   WARMTELINK_SERIAL_GID=<host-serial-gid> \
#   docker compose -f docker-compose.yml -f docker-compose.warmtelink.yml up -d
#
# Keep the stable /dev/serial/by-id path on the host: /dev/ttyUSB* names may
# change after a reboot. pyserial opens POSIX serial devices with O_RDWR, so
# Docker must grant the device cgroup rule rw (never m). This is only the
# system permission required to open the fd: the WarmteLink worker itself only
# calls read/close and has no write path. The base compose non-root user stays
# in effect; this overlay grants neither root nor privileged mode.
services:
  app:
    devices:
      - "${WARMTELINK_DEVICE_PATH:?Set a stable /dev/serial/by-id path}:/dev/warmtelink:rw"
    group_add:
      - "${WARMTELINK_SERIAL_GID:?Set the host serial device GID}"