Support multiple IP addreses

[schoentoon]

I have my wireguard configured to allow for multiple ip addresses per peer (generally ipv4 and ipv6). This is simply done like this

[Peer]
PublicKey = <snip>
AllowedIPs = 10.0.0.2/32, fd86:ea04:::4/128

However the eventual prometheus labels don't seem to pick up on this all too well. As I get the following labels:
wireguard_sent_bytes_total{inteface="wg0", public_key="<snip>", local_ip="10.0.0.2", local_subnet="32,fd86:ea04:::2"}

It seems to me that it is doing a simple split on the / and just uses the entire output after that as the local subnet.

[MindFlavor]

You are indeed right, I haven't considered the possibility of allowing multiple IP addresses 🤦‍♂️ . I can fix this but I do not know how to express multiple IPs as Prometheus label(s). Should we drop the local_subnet label and replace local_ip with a simpler allowed_ips?
Alternatively we can have local_ip_1, local_subnet_1, local_ip_2, local_subnet_2, and so on but it's ugly.

@schoentoon what do you think we should do? I'm partial for the first approach.

[MindFlavor]

I have a working solution based on the second approach. Please check out if it solves your problem!

[schoentoon]

The second approach seems better for users with only one or two ip addresses, but the first option would be better for people with a lot of ip addresses. Maybe make it configurable?
Also, while looking at this ticket again I noticed that the first label is called inteface rather than interface, thought this could have been a copy paste failure on my end. Turns out it isn't, may want to fix that too :)

[MindFlavor]

Makes perfect sense. I will implement the second approach behind a startup flag.
I will also correct the inteface :D

[MindFlavor]

ok in #9 I've implemented your suggestions. Let me know if it's ok by you!

[schoentoon]

Deployed it on my infrastructure and instantly looks a lot better. I'll have to tweak my grafana dashboards a bit now, but that's just a detail 😅
Thanks for the quick fixing :)