docs/ubus.txt

   1 ---
   2 ---
   3 uBus IPC/RPC System
   4 ===================
   5
   6 include::menu.inc[]
   7
   8 == uBus - IPC/RPC
   9
  10 uBus is the interconnect system used by most services running on a _LEDE_ setup.
  11 Services can connect to the bus and provide methods that can be called by other services or clients.
  12
  13 There is a CLI that can be used to communicate with services on the bus.
  14
  15 ----
  16 root@lede:/# ubus
  17 Usage: ubus [<options>] <command> [arguments...]
  18 Options:
  19 -s <socket>:            Set the unix domain socket to connect to
  20 -t <timeout>:           Set the timeout (in seconds) for a command to complete
  21 -S:                     Use simplified output (for scripts)
  22 -v:                     More verbose output
  23
  24 Commands:
  25 - list [<path>]                 List objects
  26 - call <path> <method> [<message>]      Call an object method
  27 - listen [<path>...]                    Listen for events
  28 - send <type> [<message>]               Send an event
  29 - wait_for <object> [<object>...]       Wait for multiple objects to appear on ubus
  30 ----
  31
  32 To find out which services are currently running on the bus simply use the list command. This will show a complete list.
  33
  34 ----
  35 root@lede:/# ubus list
  36 dhcp
  37 log
  38 network
  39 network.device
  40 network.interface
  41 network.interface.loopback
  42 network.interface.wan
  43 network.interface.wan6
  44 network.wireless
  45 service
  46 system
  47 ----
  48
  49 To find out which methods a specific service provides also use the list command but add a few more parameters to see a complete list
  50
  51 ----
  52 root@OpenWrt:/# ubus -v list system
  53 'system' @6b093875
  54         "board":{}
  55         "info":{}
  56         "upgrade":{}
  57         "watchdog":{"frequency":"Integer","timeout":"Integer","stop":"Boolean"}
  58         "signal":{"pid":"Integer","signum":"Integer"}
  59 ----
  60
  61 You can now call a remote method and receive a reply. A reply may be a simple integer return code or a more complete reply. Internally the bus uses a blob format, the CLI conveniently converts this to JSON.
  62
  63 ----
  64 root@lede:/# ubus call system board
  65 {
  66         "kernel": "4.4.6",
  67         "hostname": "lede",
  68         "system": "MIPS Malta",
  69         "release": {
  70                 "distribution": "LEDE",
  71                 "version": "HEAD",
  72                 "revision": "3",
  73                 "codename": "designated_driver",
  74                 "target": "malta\/le",
  75                 "description": "LEDE Designated Driver 3"
  76         }
  77 }
  78 ----
  79
  80 You can call a method and pass it some parameters by simply appending a JSON structure to the CLI command.
  81 ----
  82 root@lede:/# ubus call system signal '{ "pid": 123, "signum": 9 }'
  83 root@lede:/# echo $?
  84 0
  85 ----
  86
  87