docs: gluon-announce, announced, alfred

docs/features/announce.rst

+Announcing Node Information
+===========================
+
+Gluon is capable of announcing information about each node to the mesh
+and to neighbouring nodes. This allows nodes to learn each others hostname,
+IP addresses, location, software versions and various other information.
+
+Format of collected data
+------------------------
+
+Information to be announced is currently split into two categories:
+
+  nodeinfo
+    In this category (mostly) static information is collected. If
+    something is unlikely to change without human intervention it should be
+    put here.
+
+  statistics
+    This category holds fast changing data, like traffic counters, uptime,
+    system load or the selected gateway.
+
+Both categories will have a ``node_id`` key be default. It should be used to
+match data from *statistics* to *nodeinfo*.
+
+Accessing Node Information
+--------------------------
+
+There are two packages responsible for distribution of the information. For
+one, information is distributed across the mesh using alfred_. Information
+between neighbouring nodes is exchanged using `gluon-announced`.
+
+.. alfred: http://www.open-mesh.org/projects/alfred
+
+alfred (mesh bound)
+~~~~~~~~~~~~~~~~~~~
+
+The package ``gluon-alfred`` is required for this to work.
+
+Using alfred both categories are distributed within the mesh. In order to
+retrieve the data you'll need both a local alfred daemon and alfred-json_
+installed. Please note that at least one alfred daemon is required to run as
+`master`.
+
+.. alfred-json: https://github.com/tcatm/alfred-json
+
+`nodeinfo` is distributed as alfred datatype `158`, while `statistics` uses
+`159`. Both are compressed using GZip (alfred-json can handle the decompression).
+
+In order to retrieve statistics data you could run:
+
+::
+
+  # alfred-json -z -r 159
+  {
+    "f8:d1:11:7e:97:dc": {
+      "processes": {
+        "total": 55,
+        "running": 2
+      },
+      "idletime": 30632.290000000001,
+      "uptime": 33200.07,
+      "memory": {
+        "free": 1660,
+        "cached": 8268,
+        "total": 29212,
+        "buffers": 2236
+      },
+      "node_id": "f8d1117e97dc",
+      "loadavg": 0.01
+    },
+    "90:f6:52:3e:b9:50": {
+      "processes": {
+        "total": 58,
+        "running": 2
+      },
+      "idletime": 28047.470000000001,
+      "uptime": 33307.849999999999,
+      "memory": {
+        "free": 2364,
+        "cached": 7168,
+        "total": 29212,
+        "buffers": 1952
+      },
+      "node_id": "90f6523eb950",
+      "loadavg": 0.34000000000000002
+    }
+  }                                    
+
+You can find more information about alfred in its README_.
+
+.. README_: http://www.open-mesh.org/projects/alfred/repository/revisions/master/entry/README
+
+gluon-announced
+~~~~~~~~~~~~~~~
+
+`gluon-announced` allows querying neighbouring nodes for their `nodeinfo`.
+It is a daemon listening on the multicast address ``ff02::2:1001`` on
+UDP port 1001 on the bare mesh interfaces. There is no client yet (but it's
+being developed), but you can query the information using tools like ``socat``:
+
+::
+
+  # socat - UDP6-DATAGRAM:[ff02::2:1001%wlan0-1]:1001
+  nodeinfo
+
+This output is not compressed, but that is likely to change in the future. If
+you intent to use ``gluon-announced``, please contact `tcatm` in Gluon's IRC
+channel.
+
+Adding a fact
+-------------
+
+To add a fact just add a file to either ``/lib/gluon/announce/nodeinfo.d/`` or
+``/lib/gluon/announce/statistics.d/``.
+
+The file must contain a lua script and its name will become the key for the
+resulting JSON object. A simple script adding a ``hostname`` field might look
+like this:
+
+::
+
+  return uci:get_first('system', 'system', 'hostname')
+
+The directory structure will be converted to a JSON object, i.e. you may
+create subdirectories. So, if the directories look like this
+
+::
+
+  .
+  ├── hardware
+  │   └── model
+  ├── hostname
+  ├── network
+  │   └── mac
+  ├── node_id
+  └── software
+      └── firmware
+
+the resulting JSON would become:
+
+::
+
+  # /lib/gluon/announce/announce.lua nodeinfo
+  {
+     "hardware" : {
+        "model" : "TP-Link TL-MR3420 v1"
+     },
+     "hostname" : "mr3420-test",
+     "network" : {
+        "mac" : "90:f6:52:82:06:02"
+     },
+     "node_id" : "90f652820602",
+     "software" : {
+        "firmware" : {
+           "base" : "gluon-v2014.2-32-ge831099",
+           "release" : "0.4.1+0-exp20140720"
+        }
+     }
+  }

docs/index.rst

@@ -39,9 +39,9 @@ Features
    features/ntp
    features/fastd
    features/batman-adv
-   features/alfred
    features/autoupdater
    features/mesh-on-wan
+   features/announce
 
 Developer Documentation
 -----------------------