accesspoint: improve prometheus wifi-collectors

1 files changed, 66 insertions, 2 deletions

diff --git a/inventory/group_vars/accesspoints/vars.yml b/inventory/group_vars/accesspoints/vars.yml
index 8dc28aea..cb2307cd 100644
--- a/inventory/group_vars/accesspoints/vars.yml
+++ b/inventory/group_vars/accesspoints/vars.yml
@@ -145,8 +145,12 @@ openwrt_packages_add:
   - prometheus-node-exporter-lua-nat_traffic
   - prometheus-node-exporter-lua-netstat
   - prometheus-node-exporter-lua-openwrt
-  - prometheus-node-exporter-lua-wifi
-  - prometheus-node-exporter-lua-wifi_stations
+  ## we will install a custom version of these collectors, see below
+  #- prometheus-node-exporter-lua-wifi
+  #- prometheus-node-exporter-lua-wifi_stations
+  ## manually install dependencies for wifi-collectors
+  - libiwinfo-lua
+  - libubus-lua
 
 openwrt_mixin:
   /etc/sysctl.conf:
@@ -198,6 +202,66 @@ openwrt_mixin:
         iptables -P FORWARD ACCEPT
       }
 
+  /usr/lib/lua/prometheus-collectors/wifi.lua:
+    mode: "0755"
+    content: |
+      -- This is a custom version of the upstream wifi and wifi_stations collectors. We want
+      -- to know the number of stations connected but for privacy and metric cardinality
+      -- reasons we don't care for MAC addresses and other details of all connected stations.
+
+      local ubus = require "ubus"
+      local iwinfo = require "iwinfo"
+
+      local function scrape()
+        local metric_wifi_network_quality = metric("wifi_network_quality","gauge")
+        local metric_wifi_network_bitrate = metric("wifi_network_bitrate","gauge")
+        local metric_wifi_network_noise = metric("wifi_network_noise_dbm","gauge")
+        local metric_wifi_network_signal = metric("wifi_network_signal_dbm","gauge")
+        local metric_wifi_stations = metric("wifi_stations", "gauge")
+
+        local u = ubus.connect()
+        local status = u:call("network.wireless", "status", {})
+
+        for dev, dev_table in pairs(status) do
+          for _, intf in ipairs(dev_table['interfaces']) do
+            local ifname = intf['ifname']
+            if ifname ~= nil then
+              local iw = iwinfo[iwinfo.type(ifname)]
+              local labels = {
+                channel = iw.channel(ifname),
+                ssid = iw.ssid(ifname),
+                bssid = iw.bssid(ifname),
+                mode = iw.mode(ifname),
+                ifname = ifname,
+                country = iw.country(ifname),
+                frequency = iw.frequency(ifname),
+                device = dev,
+              }
+
+              local qc = iw.quality(ifname) or 0
+              local qm = iw.quality_max(ifname) or 0
+              local quality = 0
+              if qc > 0 and qm > 0 then
+                quality = math.floor((100 / qm) * qc)
+              end
+              local stations = 0
+              local assoclist = iw.assoclist(ifname)
+              for _, _ in pairs(assoclist) do
+                 stations = stations + 1
+              end
+
+              metric_wifi_network_quality(labels, quality)
+              metric_wifi_network_noise(labels, iw.noise(ifname) or 0)
+              metric_wifi_network_bitrate(labels, iw.bitrate(ifname) or 0)
+              metric_wifi_network_signal(labels, iw.signal(ifname) or -255)
+              metric_wifi_stations(labels, stations)
+            end
+          end
+        end
+      end
+
+      return { scrape = scrape }
+
   /usr/bin/list-stations:
     mode: "0755"
     content: |