rsky-relay: Add com.atproto.sync.listHosts handler

[str4d]

Summary

This implements the com.atproto.sync.listHosts endpoint.

Related Issues

https://bsky.app/profile/rude1.blacksky.team/post/3loazssauks23

Changes

• Feature implementation
• Bug fix
• Documentation update
• Other (please specify):

Checklist

• I have tested the changes (including writing unit tests).
• I confirm that my implementation aligns with the canonical Typescript implementation and/or atproto spec
• I have updated relevant documentation.
• I have formatted my code correctly
• I have provided examples for how this code works or will be used

[str4d]

indigo does things like mark a host as offline if it fails repeated connection attempts, or mark hosts that are actually relays as banned. I couldn't find any logic in rsky-relay that did this, so for now this reports the same default value as indigo. This does mean rsky-relay is over-reporting which hosts it is actively connected to, but that can be fixed by someone more familiar with the stack.

[str4d]

indigo updates its counter for a PDS host whenever an account is first observed on a PDS or is observed to move between PDSs. AFAICT rsky-relay doesn't have any tracking of which host a repo is on, so I haven't hooked this up to anything and it instead reports the same default value as indigo.

[afbase]

❯ curl "http://localhost:9000/xrpc/com.atproto.sync.listHosts?limit=10" | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  1034  100  1034    0     0    98k      0 --:--:-- --:--:-- --:--:--  100k
{
  "cursor": "10",
  "hosts": [
    {
      "accountCount": 0,
      "hostname": "reishi.us-east.host.bsky.network",
      "seq": 229148683,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "scarletina.us-east.host.bsky.network",
      "seq": 225800171,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "woodear.us-west.host.bsky.network",
      "seq": 170959567,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "verpa.us-west.host.bsky.network",
      "seq": 232327256,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "panthercap.us-east.host.bsky.network",
      "seq": 222885971,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "milkcap.us-west.host.bsky.network",
      "seq": 236909613,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "puffball.us-east.host.bsky.network",
      "seq": 636838749,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "cortinarius.us-west.host.bsky.network",
      "seq": 57424274,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "earthstar.us-east.host.bsky.network",
      "seq": 222018566,
      "status": "active"
    },
    {
      "accountCount": 0,
      "hostname": "truffle.us-east.host.bsky.network",
      "seq": 226445298,
      "status": "active"
    }
  ]
}

I was able to test successfully!

[afbase]

+1 - will wait to hear from one other dev before merge