| Filename | Latest commit message | Latest commit date |
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d1c0963fbd
A delivered matrix account needs two things: the token and the homeserver it
belongs to. Only the token was stored, so the homeserver had to ride on the
queue notice — and a notice is not persistence. Re-delivering a credential
(agent moved, hive re-provisioned, token rotated) has to reconstruct it from
somewhere, and there is nowhere; keeping it separately at swarm level would be
a second store for one logical object, free to drift from the first.
So `Credential` grows a `homeserver` field and `read`/`write` carry the whole
object rather than a bare string.
`value` keeps its name. `nix/host-modules/glue-matrix-bao-token.nix` reads the
store with `bao kv get -field=value` and is the only nix reader of it, checked
rather than assumed — so this had to be an addition, never a rename.
Two compatibility properties, both of which fail silently if broken:
KV2 keeps every prior version, so objects written before this field existed
are still decoded by this type. What tolerates their absence is the field
being `Option` — a bare `String` would not fail as a migration, every stored
credential would become unreadable at once. The new test pins that, with a
presence control so the arm is about absence being tolerated rather than the
field being ignored.
`skip_serializing_if` keeps a token-only credential serialising to exactly the
bytes the previous version wrote, with no `homeserver` key rather than a null,
which is what that nix reader would otherwise trip over. The existing test
pinning `{"value":"t"}` proves it and became the control for free.
Mutation testing earned its place here: `#[serde(default)]` was in the first
draft and its comment claimed it was what made old objects decode. Dropping it
changed nothing — serde already decodes a missing field to `None` for an
optional type — so the attribute was redundant and the comment was wrong about
its own mechanism. Both removed rather than left to mislead the next reader.
The delivery half needed no change: `write_agent_matrix_token` already took a
homeserver and already wrote the `matrix-account-<name>.json` sidecar beside
the token. `deliver` simply stops passing `None`. A credential stored without
one still works exactly as before — no sidecar, and the account needs a
configured entry.
Refs #3726
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| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||
swarm-secret-client
Reading and writing a swarm credential in the secret store, over vaultrs.
The HTTP is that crate's job. What this one owns is the agreements both
ends of the store have to state identically: where a credential lives, which
field its bytes are in, and how this deployment's environment becomes a
logged-in client.
The surrounding picture — which secret is minted where, and why delivery is a
copy rather than a bind mount — is docs/swarm/secrets.md.
Why a crate and not a module per binary
The store has two Rust ends and they are peers: the swarm controller writes a credential, a hive reads it. Neither is senior to the other, so a path formatted at each call site is an agreement with no owner — it holds right up until one side is edited alone, and then it fails as a missing key rather than as a mismatch.
The third end is what settles it. nix/host-modules/glue-matrix-bao-token.nix
reads the store with bao kv get -field=value. That reader is a shell line in
a nix module: it cannot be renamed by the same refactor as a Rust struct, and
no Rust test reaches it. So the field name is pinned by a test against the
serialised literal rather than left to the struct definition.
The identity is a certificate, and the role is the hive's name
Authentication is the store's cert auth method.
nix/host-modules/glue-bao-tls.nix mints the client certificate with its CN
set to the hive's name, because a cert-auth role matches on the CN. So
cert_role is not a free choice for the caller: a hive passes its own name,
and the policy attached to that role is what scopes what it may read.
The listener's tls_require_and_verify_client_cert is a different thing and
not a substitute. It decides who may open a connection; it says nothing about
who the connection belongs to, and a store with the option set and no cert
mount configured refuses every login made here. That refusal is what
Error::Vault out of connect means.
Configuration
Settings::from_env reads BAO_ADDR, BAO_CLIENT_CERT, BAO_CLIENT_KEY,
and the optional BAO_CACERT.
The BAO_ spellings are read explicitly rather than left to vaultrs. Its
own defaults look for VAULT_ADDR / VAULT_CLIENT_CERT / VAULT_CLIENT_KEY,
which no unit in this tree sets. Falling through to them builds a client with
no identity at all, and that surfaces as a TLS handshake failure — a place
that names neither the variable nor the reason.
Empty is as absent as unset. systemd renders an unset nix option as
Environment=BAO_CACERT=, so empty is the shape a missing value arrives in.
The certificate and key are paths, not values, and are read at connect time — same rule as every other credential in this tree, for the same reason: a value in a nix expression is rendered into the world-readable store.
Reading the environment is separate from connecting (Settings::from_lookup)
because every one of those failures is a misconfiguration an operator has to
read an error about, and none of them needs a reachable store to happen.
Names that arrive from elsewhere
path::matrix_account is fallible, which for a string formatter needs saying:
its segments are an agent name from the topology and an account name from that
agent's own config. A / turns one agent's segment into another agent's
directory and .. walks out of the prefix entirely, so the charset it accepts
is deliberately narrower than what the store would.
What this crate does not do
It has no opinion on what a caller may read. That is the policy attached to the cert role, and it lives in the store.
It holds the token minted at login and renews nothing. A handle is built per credential, so the login is the cheap part of a rare operation — a caller that wanted to keep one alive across a token's lifetime would need more than this.