dbus

A block that provides dbus allowing communication among services. Unlike the hostOS dbus in balenaOS, you can use this block as base and provide custom dbus configurations.

How to use

Add the dbus block as a service in your docker-compose file to start a single bus. The default is to start a bus with the "session" bus config on TCP port 55884.

version: "2"
services:
  dbus:
    image: bh.cr/balenalabs/dbus
    restart: always

You can also start a bus with the "system" config by overriding the DBUS_CONFIG environment variable.

version: "2"
services:
  dbus-session:
    image: bh.cr/balenalabs/dbus
    restart: always
    environment:
      DBUS_CONFIG: session.conf
  dbus-system:
    image: bh.cr/balenalabs/dbus
    restart: always
    environment:
      DBUS_CONFIG: system.conf

Configure your services requiring access to dbus to use the TCP addresses of the containers providing the busses

Example:

export DBUS_SESSION_BUS_ADDRESS=tcp:host=dbus-session,port=55884
export DBUS_SYSTEM_BUS_ADDRESS=tcp:host=dbus-system,port=55884

Alternatively, the server can listen on UNIX domain sockets. Your container can connect to this bus by sharing the socket through a named volume and specifying the appropriate environment variable:

version: "2"
volumes:
  dbus:
services:
  dbus-session:
    image: bh.cr/balenalabs/dbus
    environment:
      DBUS_ADDRESS: unix:path=/run/dbus/session.sock
    volumes:
      - dbus:/run/dbus
  my-app:
    build: ./app
    volumes:
      - dbus:/run/dbus
    environment:
      DBUS_SESSION_BUS_ADDRESS: unix:path=/run/dbus/session.sock

Customization

Extend image configuration

You can extend the dbus block to include custom configuration as you would with any other Dockerfile. Just make sure you don't override the ENTRYPOINT as it contains important system configuration.

Example:

FROM bh.cr/balenalabs/dbus

COPY example.conf /etc/dbus-1/system.d/

COPY mystartscript.sh /usr/src/

CMD [ "/bin/bash", "/usr/src/mystartscript.sh" ]

Environment variables

Environment variable	Description	Default	Options
DBUS_PORT	The port on which the bus listens, only for TCP sockets	55884	-
DBUS_CONFIG	The config file to use for the bus, relative to /usr/src/app	session.conf	-
DBUS_ADDRESS	The address to listen on, allows using UNIX domain sockets	-	-