hyperhive/nix/host-modules/swarm-secret-publisher.nix
atlas 276bf8531a nix: inline the swarm sub-path aliases at their use sites
autheliaCfg/forgeCfg/vmCfg/vlCfg were local re-exports of
hyperhiveCfg.swarm.<subpath> — a shape that hides the full option
path from grep, the same hazard #4356 fixed for the tls alias.
Removed the six let-bindings and spelled the full
hyperhiveCfg.swarm.<subpath>.<field> path at every use site instead.

None of the read fields (url, machine, hiveClientPrefix,
agentClientSuffix, domain, port) sit on the old side of a
mkRenamedOptionModule in deploy.nix, so inlining the alias's own
current path is correct as-is.

Refs #4363

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-09-13 20:02:20 +02:00

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# The unit that copies authelia's minted OIDC client secrets into the swarm's
# secret store, so whoever needs one can read it there: a hive its agents'
# credential, a swarm service its own.
#
# ⚠️ "Whoever", including a reader on THIS host. A swarm service's secret goes
# into the store even when the service runs beside authelia, because its
# reader fetches it from the store in every deployment — ./swarm-grafana.nix
# states the ruling that made that the only route. Publishing "only when the
# reader is elsewhere" would be a second shape of this unit, gated on a fact
# about another host, to save a round trip on the one host that can afford it.
#
# ⚠️ IT RUNS WHERE AUTHELIA DOES, and that is the whole reason it exists as a
# separate thing. `deploy.authelia.hostClientSecretDir`'s own description says
# why: the plaintext's other reader lives in a **different container**, and
# containers that share this host's network namespace still have separate
# filesystem roots, so "the host is the only place both trees are addressable".
# A delivery step therefore runs on the host that mints — not on the store's
# host, and not on the reading hive's.
#
# ⚠️ ITS OWN STORE IDENTITY, not swarm-controller's. That principal may rewrite
# every hive's policy and login role; a unit whose entire job is copying one
# file has no business holding it. ./swarm-bao.nix grants this one
# `create`/`update` under the hive prefix and nothing else.
#
# ⚠️ THE SECRET NEVER REACHES `argv`. `bao` is an external binary, so every
# argument is world-readable in /proc for the life of the call — the value is
# passed as `@<path>` and read by bao itself. (`/knowledge/secret-hygiene.md`:
# "a path keeps the secret out of the store, and reading it into a shell
# variable puts it straight into argv".)
{
pkgs,
lib,
config,
...
}:
let
hyperhiveCfg = config.services.hyperhive;
deployCfg = hyperhiveCfg.deploy;
baoDeploy = deployCfg.bao;
cfg = deployCfg.swarm-secret-publisher;
# A reader is defined by holding a certificate the store accepts, never by
# standing next to it — the rule ./glue-matrix-bao-token.nix states in full.
# `deploy.bao.enable` here would be the co-location assumption itself.
haveClientIdentity = cfg.baoClientCertFile != null && cfg.baoClientKeyFile != null;
# Both halves have to be here: the mint (authelia, for the plaintext) and an
# identity (for the store). Neither implies the other.
active = hyperhiveCfg.enable && cfg.enable && deployCfg.authelia.enable && haveClientIdentity;
hiveNames = lib.attrNames hyperhiveCfg.swarm.hives;
# The client id agent containers present, per hive — composed exactly as
# ./swarm-authelia.nix composes it, from the same two read-only options, so a
# rename there cannot leave this spelling behind.
agentClientId =
hive:
"${hyperhiveCfg.swarm.authelia.hiveClientPrefix}${hive}${hyperhiveCfg.swarm.authelia.agentClientSuffix}";
# The swarm's own services, as opposed to its hives. One client for the whole
# swarm rather than one per hive, so one value in the store rather than a copy
# each: `swarm/services/<id>/oidc/client`, under the `services` kind
# `swarm-secret-client`'s `path::Kind` declares.
#
# The ids come from `swarm.*`, which is identical on every host — that is what
# lets this host name a service's client while running none of them, and it is
# the same read the service's own module registers the client with. A swarm
# that runs no Grafana mints no secret for it, so its entry skips below rather
# than needing a condition here.
serviceClientIds = [ hyperhiveCfg.swarm.grafana.oidc.clientId ];
in
{
options.services.hyperhive.deploy.swarm-secret-publisher = {
enable = lib.mkOption {
type = lib.types.bool;
default = deployCfg.authelia.enable;
defaultText = lib.literalExpression "deploy.authelia.enable";
description = ''
Publish the OIDC client secrets this host mints into the swarm's
secret store, so a hive that does not run authelia can read its
agents' credential and a swarm service can read its own from
wherever it runs, this host included.
Defaults to whether this host mints them, which is the only half of
the question that is a property of *this* host.
Deliberately **not** `deploy.bao.enable`. That asks whether the
store stands here, and a publisher beside a remote store, holding a
leaf issued out of band, is a deployment this exists to serve
defaulting on co-location would leave exactly that shape silently
publishing nothing. Whether the wiring is complete is the client
identity's job (see `baoClientCertFile`), not this option's.
Turning it off leaves every hive but this one without its agents'
credential, and the swarm's Grafana without any login at all its
secret has exactly one route and this is the producer's end of it. So
the honest reason to set it false is a deployment delivering those
secrets by some other mechanism it owns.
'';
};
baoClientCertFile = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = null;
description = ''
Client certificate this publisher presents to the store. Its subject
must be {option}`services.hyperhive.deploy.bao.secretPublisherCommonName`
cert auth matches on the CN, and the role accepts nothing else.
No default: a module that guessed would be holding the CA opinion
./swarm-bao.nix deliberately does not hold.
./glue-secret-publisher-bao-identity.nix points it at the leaf
./glue-bao-tls.nix mints, where this host mints one.
'';
};
baoClientKeyFile = lib.mkOption {
type = lib.types.nullOr lib.types.str;
default = null;
description = ''
Private key for {option}`services.hyperhive.deploy.swarm-secret-publisher.baoClientCertFile`.
Both or neither the unit does not exist unless each is set.
'';
};
};
config = lib.mkIf active {
services.hyperhive.swarm.otel.journaldUnits = [ "swarm-secret-publish" ];
# Re-publish when authelia rotates a secret. The mint writes the file, so
# the file is the event — there is no signal from authelia to subscribe to.
systemd.paths.swarm-secret-publish = {
description = "watch for minted OIDC client secrets to publish";
wantedBy = [ "multi-user.target" ];
pathConfig = {
PathChanged = deployCfg.authelia.hostClientSecretDir;
Unit = "swarm-secret-publish.service";
};
};
systemd.services.swarm-secret-publish = {
description = "publish minted OIDC client secrets to the swarm secret store";
wantedBy = [ "multi-user.target" ];
after = [ "network.target" ];
path = [
baoDeploy.package
pkgs.coreutils
];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
# Bounded here rather than left to systemd's default, so the number a
# boot waits on is in the file that waits. A sealed store answers on
# the port and never answers the write.
TimeoutStartSec = 60;
Restart = "on-failure";
RestartSec = 30;
};
environment = {
BAO_ADDR = "https://${hyperhiveCfg.swarm.bao.domain}:${toString hyperhiveCfg.swarm.bao.port}";
BAO_CLIENT_CERT = cfg.baoClientCertFile;
BAO_CLIENT_KEY = cfg.baoClientKeyFile;
}
// lib.optionalAttrs (baoDeploy.serverCaFile != null) {
BAO_CACERT = baoDeploy.serverCaFile;
};
script = ''
set -euo pipefail
# Cert auth is a login, not a transport setting. The `BAO_CLIENT_*`
# variables above only decide which certificate the TLS handshake
# presents; without a token `bao` asks its token helper instead, and
# that is a `sh` this unit's `path` does not carry. `-token-only`
# answers on stdout and skips the helper on both sides.
#
# Unhandled on purpose: `Restart=on-failure` above is what a store that
# cannot authenticate this host should get. Degrading here would report
# "published 0" as an ordinary quiet day.
BAO_TOKEN="$(bao login -method=cert -token-only)"
export BAO_TOKEN
published=0
skipped=0
${lib.concatMapStringsSep "\n" (hive: ''
src=${lib.escapeShellArg "${deployCfg.authelia.hostClientSecretDir}/${agentClientId hive}.secret"}
if [ -s "$src" ]; then
# `value=@$src` hands bao the PATH: bao opens the file itself, so
# the plaintext is never an argument of this process. Writing it as
# `value="$(cat "$src")"` would publish it to /proc for anyone on
# the host to read.
bao kv put ${lib.escapeShellArg "secret/swarm/hives/${hive}/queue/agent"} \
value=@"$src" \
client_id=${lib.escapeShellArg (agentClientId hive)}
published=$((published + 1))
else
# Not an error: authelia mints on its FIRST BOOT, so an absent file
# is "not yet", and the path unit above re-runs this when it lands.
echo "no minted secret at $src yet; the path unit will re-run this" >&2
skipped=$((skipped + 1))
fi
'') hiveNames}
${lib.concatMapStringsSep "\n" (id: ''
src=${lib.escapeShellArg "${deployCfg.authelia.hostClientSecretDir}/${id}.secret"}
if [ -s "$src" ]; then
# `value=@$src` for the same reason as the hive loop above: bao
# opens the file itself, so the plaintext is never an argument of
# this process.
#
# No `client_id` field beside it, unlike a hive's credential: that
# one is derived per hive and has to be reconstructable from the
# store alone, whereas a service's client id is the swarm-wide
# option both ends already read.
bao kv put ${lib.escapeShellArg "secret/swarm/services/${id}/oidc/client"} \
value=@"$src"
published=$((published + 1))
else
# Not an error, and the ordinary state of a swarm that runs this
# service nowhere: nothing registered the client, so authelia minted
# nothing to publish.
echo "no minted secret at $src yet; the path unit will re-run this" >&2
skipped=$((skipped + 1))
fi
'') serviceClientIds}
echo "published $published client secret(s), skipped $skipped"
'';
};
};
}