prometheus-node-exporter-lua: uci_dhcp_host module

Extract data from configuration file /etc/config/dhcp and create labels
{name, ip, mac, dns} via uci. Those labels are useful in order to craft
complex prometheus queries as replacing the MAC address to a custom
name.  E.g.: wifi_station_signal_dbm * on (mac) group_left(name)
uci_dhcp_host or on (mac) label_replace(wifi_station_signal_dbm, "name",
"$1", "mac", "(.+)")

Signed-off-by: Gérondal Thibault <contact@tycale.be>

1 files changed, 15 insertions, 0 deletions

diff --git a/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/uci_dhcp_host.lua b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/uci_dhcp_host.lua
new file mode 100644
index 000000000..950962599
--- /dev/null
+++ b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/uci_dhcp_host.lua
@@ -0,0 +1,15 @@
+local uci=require("uci")
+
+local function scrape()
+  local curs=uci.cursor()
+  local metric_uci_host = metric("uci_dhcp_host", "gauge")
+
+  curs:foreach("dhcp", "host", function(s)
+    if s[".type"] == "host" then
+      labels = {name=s["name"], mac=string.upper(s["mac"]), dns=s["dns"], ip=s["ip"]}
+      metric_uci_host(labels, 1)
+    end
+  end)
+end
+
+return { scrape = scrape }