hyperhive/swarm-authelia-bridge
Repository files (latest commit first)
Filename Latest commit message Latest commit date
atlas a248db1fa2 feat(swarm-authelia-bridge): report a heal as its own outcome
`EnsureAgentIdentity` answered `AlreadyExists` whether it had added the
agent marker to an existing subject or done nothing at all, and the
controller discarded the answer outright. So the one case worth telling
a human about — a subject that was NOT an agent a moment ago — could not
survive the socket, let alone reach a log.

`Healed` is a variant rather than a field on `AlreadyExists` because a
field is ignorable: adding a variant makes every existing match fail to
compile until its author decides what a heal means. That is the property
the old shape lacked.

The store cannot tell a pre-marker agent identity from a human operator
account created without a group — both are `groups: []`. So this is
either the intended migration or an agent joining a person's live SSO
account, and only the caller has the context to tell them apart.

Gated by state/gate-3549-heal.sh (8 arms + mutation): the mutation
collapses Healed back and reddens the discriminating arm while leaving
the anti-noise arm green. The W' control asserts exactly one warn in the
whole run, so a build that warned on every routine ensure would fail.
2026-08-23 19:00:41 +02:00
..
src feat(swarm-authelia-bridge): report a heal as its own outcome 2026-08-23 19:00:41 +02:00
Cargo.toml fix(#3344): type the roster entry's name as Ident, per review 2026-08-20 00:15:48 +02:00
README.md feat(swarm-authelia-bridge): mark agent identities with a group, and answer for the set 2026-08-20 00:15:48 +02:00

swarm-authelia-bridge

The only thing allowed to write swarm-authelia's users database.

Why this exists

swarm-controller's CreateIdentity job needs to add an agent as an authelia subject, but swarm-controller runs unprivileged and does not own users.yml — a different uid does (authelia-swarm, the user services.authelia.instances.swarm runs as). Root/CAP_CHOWN/a shared group were all examined and rejected during this crate's design thread — see swarmctl/README.md's identical analysis of this same file, written before this crate existed.

The fix: run this process as User = "authelia-swarm"; instead — inside the swarm-authelia container, alongside authelia itself — so it simply owns the file it writes. No elevated privilege anywhere.

Shape

  • One endpoint, POST /requests, body = swarm-authelia-bridge-sock's BridgeRequest verbatim — EnsureAgentIdentity (idempotently ensure an agent exists as an authelia subject) and ListAgentIdentities (the roster: the subjects carrying the agent marker group, names only).
  • Bearer-authenticated via authelia's own OIDC token introspection (RFC 7662), against swarm-controller's existing machine-client identity (already minted for the queue connection) — no new credential.
  • No restart of authelia after a write — relies on authentication_backend.file.watch, confirmed working against the pinned 4.39.20 build during this design work.
  • Network-facing rather than unix-socket-only: swarm-authelia's container shares the host netns, so the same listener serves both a co-located swarm-controller (loopback) and a split-host one (bind wider + firewall) with no separate transport.

One store, two writers

This bridge and swarmctl both read and write authelia's users.yml directly. That is the whole arrangement — neither keeps a private copy it considers canonical.

It used to be otherwise, and the seam was real: each side had its own users.json treated as authoritative, rendering the same physical users.yml. A writer whose own JSON was missing could not tell "nothing here yet" from "someone else's users", so it refused to write at all — which is exactly what a hive with existing users hit (#3422).

What still has to hold, since two processes share the file:

  • Read before write. Both do, so neither can drop a user the other added between operations.
  • Unknown keys survive. Both carry unmodelled top-level and per-user fields through a round-trip, or whichever writes second would silently delete what the first added.
  • Every user gets an email. A relying party asking for the claim fails rather than degrades, so both write paths fill in a synthetic address when none was supplied.

Neither restarts authelia: it watches the file. swarmctl could (it is root); this bridge deliberately cannot, and a reload that depends on which process wrote is not a reload.