#218

Nov 20, 2022

Work

This was a pretty good week. The team is coming to the end of a few projects which have been running for the last couple of quarters, so it’s time to start scoping new work.

One of those pieces of work is overhauling our “banking events” stream—which carries data about payments, refunds, chargebacks, etc—so that we can change some of our API logic to draw data from the event stream, rather than the banking database tables. This will then let us start to extract banking data to a separate service, so it’s more easy to scale our banking layer.

And I’m leading it, which is great. I’ve been hoping to take on a sizeable project for a while, and now I’ve got it.

Books

No books this week!

Roleplaying Games

GoAdventuring

We decided to pause the campaign.

I messaged the group to see who was interested in sticking with it, and I got three positive responses, which is about what I expected. But one of those people is away most of December, and one of them can’t make the Tuesday sessions. So we decided to put the game on hiatus until January when we’ll regroup for a new session 0.

Cartographic Curiosities

I had plans for this week’s session but, as the saying goes, no plan survives contact with the players.

So it went off the rails, but it was still a lot of fun! This week, the party lept through their first Fairy Door, walked the strange roads of that magical land, and ended up somewhere across the forest in only one day, despite feeling like they had spent two days on the road. Fortunately, they came out next to a (normal, human) road, and so quickly found their bearings, and now know a shortcut (maybe) between the east and west of the wood.

Then one of the PCs got themselves magically hurled through the sky, many miles north, and onto a small island with high cliffs and no bridge to the mainland. I didn’t really know how to handle this (the rest of the party had no way of knowing where they’d gone) but fortunately we were coming close to the end of the session, so I ended with some spooky druids ambushing that PC and saying “you will come with us, for questioning.”

I don’t really want to run two independent groups, but by a stroke of great fortune, 3 of the 5 players are away next session, and one of the players who’s still around is the one who got themselves teleported!

So rather than cancel that week, I’ll just run a 1-on-1 session with that player, and we’ll work through their druid situation. I’m sure we can reunite the party with a little metagaming, if the other PCs decide “well, she’s vanished, but maybe she’s gone back to our main base in the other town” they can all reunite there. I feel a bit bad for the other player who’s still around, but they’d have been missing out if I’d cancelled, too.

Wicked Ones

This week, the campaign came to an end.

The PCs had teamed up with another monster faction to take on a significantly more powerful good faction. However, this good faction had just finalised its plans to attack the PCs and their allied monster faction: so I decided the three raids (good vs PCs, good vs monsters, PCs+monsters vs good) would take place simultaneously. The PCs would face less opposition than they expected on their raid, and would return home to find their dungeon in the middle of being cleaned out by the good faction.

Things went awry and Trava the Bugbear got knocked out, with Moordred the Minotaur and Slikidlorbin the Kobold taking a lot of damage. They managed to escape, but ultimately the raid was a botch and they rolled some major consequences. So I upgraded the force that was attacking their dungeon: they arrived, pretty beaten up and low on resources, to find even more troops than they had just fought.

There were some daring shenanigans, cunning tricks, and many dead NPCs, but ultimately Trava and Moordred were killed and Slikidlorbin escaped. Rather than bring in replacement PCs, we decided to just do a vignette for how things turned out for Slikidlorbin 10 years later, and ended it there.

Next week will be session 0 of Traveller! I’m going to see if I can rustle up one or two more players, I think 4 works better than 3, but regardless I’m really looking forward to it.

Would I play Wicked Ones again? I’m not sure, maybe. I didn’t like everything, but I liked a lot. Even if I never return to it, this was a good experience.

Miscellaneous

This week I fixed a couple of performance issues with resolved which my work laptop suddenly started triggering on Monday. If it got unlucky with which records were chosen to resolve a query, it would take up to several minutes to complete.

Essentially, there were two problems with how responses like this were handled:

; <<>> DiG 9.18.7 <<>> @a.gtld-servers.net easydns.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31706
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 4, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;easydns.com.                   IN      A

;; AUTHORITY SECTION:
easydns.com.            172800  IN      NS      dns3.easydns.org.
easydns.com.            172800  IN      NS      dns1.easydns.com.
easydns.com.            172800  IN      NS      dns2.easydns.net.
easydns.com.            172800  IN      NS      dns4.easydns.info.

;; ADDITIONAL SECTION:
dns1.easydns.com.       172800  IN      AAAA    2400:cb00:2049:1::a29f:1835
dns1.easydns.com.       172800  IN      A       64.68.192.10

;; Query time: 21 msec
;; SERVER: 2001:503:a83e::2:30#53(a.gtld-servers.net) (UDP)
;; WHEN: Sun Nov 20 21:01:18 GMT 2022
;; MSG SIZE  rcvd: 194

Here we have a domain, easydns.com., which has four nameservers, dns1.easydns.com., dns2.easydns.net., dns3.easydns.org., and dns4.easydns.info.. These nameservers are all using different TLDs so that if (say) com., net., and org. are simultaneously down, at least you can still resolve domains via info.1

We only get an A record for dns1.easydns.com., and that’s correct behaviour since the other nameservers are not subdomains of easydns.com.. But resolved did not handle that very well: it would see those four nameservers, say “great, a delegation, I know how to handle delegations!” and pick an arbitrary one to resolve easydns.com. with.

But at this point we only know the IP address for dns1.easydns.com., so if it arbitrarily picks any of the other three, it ends up having to resolve those, which has two issues: firstly, we make avoidable network requests, which slows things down; secondly, it’s possible to get stuck in a loop, where to resolve (say) dns1.easydns.com. you need to resolve dns1.easydns.com.!

So I made a few improvements:

  1. Bail out if we get a loop in our questions. This was already gracefully handled by the recursion limit, but we could do significantly better than going around a loop 32 times. (PR#197)

  2. When resolving a nameserver, if we get back a glue record for that very nameserver, just use that as the answer. (PR#198)

  3. When choosing which nameserver to use to resolve a query, do two passes: on the first pass, try any nameservers whose IP addresses we already know; if none of those worked, on the second pass also try the nameservers whose IP addresses we need to first resolve. (PR#200)

Some might say “well, by writing your own DNS resolver you’re asking for weird bugs like this”, but this is only the second problem I’ve had since I started running resolved as the DNS server for my LAN back in March. I’ve had more problems with off-the-shelf stuff.

That’s a pretty good track record.

  1. Though, if com., net., and org., are down we’re probably in a global thermonuclear war, right? What else could do it? Well, I guess EasyDNS’s customers will still be able to resolve their websites while the world burns…↩︎