ha-syslog-devtracker

A real-time device tracker for Home Assistant based on syslog events. The tracker depends on syslog forwarding on a Linux-based dnsmasq DHCP server and hostapd, including routers based on OpenWRT/LEDE.

Due to the nature of how DHCP works, it is most suitable for detecting when devices come online. Detecting when devices go offline may be subject to delays, especially regarding wired devices. In general it works well for wireless devices. See the notes below for more information.

Supported message formats:

• dnsmasq
• hostapd

Configuration

Copy syslog.py to the custom_components/device_tracker/ directory of your Home Assistant configuration directory.

Next, add the following configuration:

device_tracker:
- platform: syslog
  host: 0.0.0.0
  port: 514
  devices:
    a1b234567890: ben
    d9e87654321f: server

You can add an arbitrary number of MAC address to device name pairs. Make sure the MAC address is lowercase and without colons.

Notes

Wireless devices

Since wireless devices may disconnect/timeout when they are idling (e.g. to preserve battery -- especially Apple devices), a grace time will be configurable during which the device will remain marked as active.

The recommended grace time is about 5 minutes and should be configured globally or per device.

Wired devices

While it is straightforward to detect devices coming online based on the DHCP requests, detecting when a wired device has gone offline is more complicated since this does not appear in the log messages.

If you are interested in tracking wired devices, you should set a reasonable DHCP lease timeout so that devices that do not renew their lease within that period can be marked offline.

TODO

This is a work in progress.

• Only UDP based forwarding is currently supported. TCP support is planned.
• Implement a (syslog origin) whitelist to prevent other hosts on the network from sending spoofed messages, especially in UDP mode; currently we assume the network can be trusted.
• Do something useful with the fact that we can have multiple log sources.

Future work

• Considering implementing a method to "ping" devices (e.g. using the IP learned from DHCP) to periodically to test if they are still online.