Here is a snippet:
include "/etc/bird.d/anycast_prefixes.conf";
function anycast_advertise()
{
if defined(ACAST_PS_ADVERTISE) then
return net ~ ACAST_PS_ADVERTISE;
else {
return false;
}
}
The content of /etc/bird.d/anycast_prefixes.conf is
define ACAST_PS_ADVERTISE =
[
192.168.200.1/32, # Frontend 1
192.168.200.2/32 # Frontend 2
];
The defined function complains about missing variables.