After adding two OpenWrt based access points to my home network (1, 2), I wanted to see the number of connected WLAN devices in my Munin monitoring installation.
I already did that in 2022 for DD-WRT and now needed the same functionality for OpenWrt.
Fortunately OpenWrt's ubus API is nicely documented, and so I built a new Munin plugin openwrt-wifi-devices_ that uses curl and jq to obtain a session ID, fetch network interfaces and then fetch the connected clients for each network interface.
Today my munin-contrib patch was merged, and you can enjoy it, too.
The screenshot shows the combined view of connected WLAN devices across multiple access points. (Its setup is described on my dd-wrt-munin blog post.) Raw data are provided by Munin plugins dd-wrt-wifi-devices_, fritzbox_wifi_devices.py of fritzbox-munin and my new openwrt-wifi-devices_.