docs/ubus.txt

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