# Swarm Matrix homeserver Private Matrix homeserver (matrix-tuwunel — the conduwuit successor) wrapped in a nixos-container (`hive-matrix`), plus optional fluffychat-web client at `chat./` (the `gatewayHost` vhost). A swarm runs one homeserver, on one host. Two namespaces configure it: - `services.hyperhive.swarm.matrix.*` — what the homeserver **is**, as every hive sees it: `serverName`, `gatewayHost`, `apiUrl`, `allowEncryption`. - `services.hyperhive.deploy.matrix.*` — what the host running it decides: `enable`, `gui.package`, `trustedServers`, `maxRequestSize`, `sso.clientSecretFile`. Vhost routing lives in [`gateway.md`](../networking/gateway.md). ## Container shape Same shape as [`gateway.md::hive-forge container shape`](../networking/gateway.md): - Container name `hive-matrix` (not `h-*`) so c0re's lifecycle scanner ignores it; operator manages via the standard `nixos-container` CLI. - Keeps hive-matrix from fighting any `services.matrix-*` the operator already runs on the host — separate systemd namespace, separate state dir. - Container runs in a network namespace of its own (`privateNetwork = true`) on the hive bridge, and binds no TCP port. Agents reach the homeserver at `chat.` via the gateway, which dials its unix socket (see [Reach](#reach)). - Persistent state at `/var/lib/nixos-containers/hive-matrix/var/lib/matrix-tuwunel/` survives container restart / host reboot. To wipe, destroy the container. ## Identity vs API listener: `serverName` vs `gatewayHost` Two distinct hostnames: - **`serverName`** — matrix-spec `server_name`, embedded *irrevocably* in every `@user:` and `!room:` identifier minted on this homeserver. You can't change it later without abandoning every account and chat history. Defaults to the bare `services.hyperhive.swarm.domain`. - **`gatewayHost`** — the API listener hostname, where the gateway's matrix vhost proxies `/_matrix/*` to tuwunel. Defaults to `chat.`. Set to `null` to skip the gateway vhost, which leaves nothing able to reach the homeserver. Both default under the **swarm** domain, because a swarm runs one homeserver: tying its identity to a single hive's domain would make relocating the container between hives look like a different homeserver. ⚠️ **they're still not interchangeable, and the difference is the cost of changing one.** `gatewayHost` is a routing detail clients rediscover through `.well-known`, so it's safe to move on a running deployment. The controller's host serves that `.well-known` on the swarm domain, and a homeserver pinned to a hive domain gets it on that hive's vhost. The matrix id format bakes `serverName` into every user and room id, so adopting a new one does **not** rename the existing users and rooms — it strands them, because their ids still name a homeserver that no longer answers.
Pinning serverName on a homeserver with existing ids `serverName` defaults to the bare `services.hyperhive.swarm.domain`. A homeserver that changes `serverName` after minting ids strands its existing users and rooms — keep the value it minted them under: ```nix services.hyperhive.swarm.matrix = { # whichever this deployment already uses serverName = config.services.hyperhive.domain; gatewayHost = "matrix.${config.services.hyperhive.domain}"; }; ``` A rebuild on a host that already has a homeserver prints a `hive-matrix: WARNING — … serverName is unset` line when this is missing, naming the value it's about to default to. It never fails the rebuild, so pin the value before the homeserver mints any ids under the default. A pinned hive domain answers `.well-known/matrix/*` itself, built from `gatewayHost`, on any host that runs that hive's gateway. It doesn't need the homeserver on the same host.
## Reach tuwunel binds no TCP port. It listens on the unix socket `/run/hive-matrix/tuwunel.sock`, in a host directory (`root:nginx`, `0770`) bind-mounted into the container, and the gateway's `/_matrix/` location proxies to that socket. Clients, agents, hive-c0re and federation peers all reach the homeserver at `chat.` through the gateway; from outside the host that takes `gateway.openFirewall`. hive-c0re does not talk to the homeserver: matrix is swarm-level, and the hive has no matrix API URL to set. Federation peers find the homeserver through `.well-known/matrix/server` at the server name, which names `:443` ([`gateway.md::Discovery flow`](../networking/gateway.md#discovery-flow-matrix)). Port 8448 isn't used. Outbound, the container sits on the hive bridge like the CI runner: it leases an address from the gateway's DHCP, resolves through its dnsmasq, and leaves through the bridge's NAT. It reaches the secret store, authelia and federation peers by name. ## Provisioning flow (appservice) Registration is closed. **The swarm's appservice** creates accounts: agents never see an appservice token, and an agent only ever receives its own `access_token`. The appservice has no URL (`url: null` in its registration), so the homeserver never calls out to it and there is no service to run. What the registration buys is an identity the homeserver recognises — which is why no secret has to be equal on both sides of the wire, and why account creation doesn't depend on registration being open to anyone who learns a token. 1. **`swarm-matrix-ctl appservice render`**, inside the `hive-matrix` container and before tuwunel starts, renders the registration to `/var/lib/swarm-matrix-appservice/swarm.yaml` (mode `0600 root:root`) from the `as_token` and spec-required `hs_token` beside it. It mints them only on a container that has none, and never reaches the store, so a store outage can't keep the homeserver down. 2. **systemd `LoadCredential=`** copies the registration into `/run/credentials/tuwunel.service/swarm-appservice.yaml`, owned by tuwunel's dynamic user with mode `0400`, at service start. The source file stays `root:root 0600` — no `chown :tuwunel` / `chmod 0640` / GID-pin gymnastics required. Keeps `DynamicUser = true` + `PrivateUsers = true` intact. 3. tuwunel's `appservice_dir` points at the credentials directory. It reads only `.yaml`/`.yml` entries from there, so the sibling credentials are invisible to it. The `.yaml` suffix on the credential id is what makes this work. 4. **hive-c0re** holds no appservice token, creates no account and does not talk to matrix. 5. **`swarm-controller` creates every account**: each agent's, with its token stored at `swarm/agents//matrix/main` for the agent's `hive-matrix-daemon` to read as the agent itself, and each hive's sender account (below). A homeserver whose `swarm-matrix-ctl` has no store identity (`services.hyperhive.deploy.matrix.ctlBaoClientCertFile`) loads no registration, and nothing creates accounts on it. On the store's host `ctlBaoClientCertFile` / `ctlBaoClientKeyFile` default to the leaf `glue-bao-tls.nix` mints there. A homeserver host without the store gets no default, even when it holds the hive's own reader `deploy.bao.clientCertFile`: issue a leaf whose subject is `deploy.bao.matrixCtlCommonName`, place it, and name it in both options. Until you do, `swarm-bao-matrix-oidc` fails naming both. ### The swarm's appservice, and its admin sender The registration's id is `swarm`, its sender `@swarm`, and its user namespace non-exclusive. It's the swarm's identity on the homeserver: `swarm-controller` creates every agent's account and every hive's sender account with it. The swarm secret store holds the registration's tokens, at `swarm/controller/swarm-controller/matrix/appservice-registration`. `swarm-matrix-ctl appservice render` renders the registration tuwunel loads as a credential from the copy of them in the `hive-matrix` container, before tuwunel starts and without the store. `appservice sync` runs beside tuwunel on a timer. The store's tokens win: when they differ from the container's, it writes them there. It restarts tuwunel whenever the registration is newer than tuwunel's last start, so the next run retries one that failed after writing. A store that holds none takes the container's tokens with a create-only write, so a running swarm keeps its value, and a container that has none mints a pair. `sync` then writes the `as_token` to `swarm/controller/swarm-controller/matrix/appservice-token`. No hive's policy reaches either path: only matrix-ctl (which holds `create` and `read` on the registration, and writes the token) and `swarm-controller` (which reads only the token) hold a grant. `@swarm` is the **one** account the homeserver promotes to admin at boot (`admin_execute`). Only those two principals read its token, which is the difference from the hive sender below: every hive reads its own sender's token. `swarm` is a reserved name, so nothing can create an agent as this account. `swarm-controller` mints each agent's account with the device id `hyperhive-`, and a login on that device replaces its token. The controller therefore reads the stored token back with `whoami` every five minutes and re-mints only when it's missing, unknown to the homeserver, or someone else's. An agent's daemon picks a re-minted token up on its next start, and a timer restarts it while it's down. ### Operators are homeserver admins Every member of authelia's `admins` group who has a matrix account is a homeserver admin. `swarm-controller` reads the group through `swarm-authelia-bridge` at start and every five minutes after, and for each member not yet in `#admins:` it sends `!admin users make-user-admin @:` there as `@swarm`. `` is the authelia username lowercased, the account an SSO login lands on. - **Leaving `admins` revokes what the sync granted.** The controller records each account it sends a grant for in `/var/lib/swarm-controller/operator-matrix-admins.json`. When one of them is no longer in `admins` but still in `#admins`, it sends `!admin users force-leave-room @: ` there as `@swarm`; leaving that room is what ends homeserver admin. - **Admins the sync didn't make keep admin.** An admin missing from that file, `@swarm`, the server user `@conduit:`, every agent's account, and every user id in `services.hyperhive.swarm.matrix.adminSync.ignoreUsers` are never revoked. - **The last admin stays.** A revoke that would leave no admin in `#admins` besides `@swarm` and the server user isn't sent; the controller logs a warning on each pass instead. - **No account, no grant.** A member who has never logged in to matrix has no account to promote. The first pass after their first SSO login promotes them. - **One command per account per controller run.** A member still missing from `#admins` after the controller sends its grant gets a `make-user-admin … failed to take` warning in the controller log on each later pass, and no second command until the controller restarts; a revoke that leaves its account in `#admins` gets `force-leave-room … failed to take` the same way. - Runs only on a controller with both `services.hyperhive.deploy.swarm-controller.authBridgeUrl` and `services.hyperhive.deploy.swarm-controller.matrixHomeserverUrl` set. ### A hive's sender account, and why it isn't an admin `@hive-:` is the account a hive acts as. `swarm-controller` creates it with the swarm's appservice token, for every hive in its directory. It's an **ordinary account**: nothing promotes it; the homeserver's `admin_execute` promotes only `@swarm`. **One account per hive.** The localpart carries the hive's name, so a swarm whose hives share a homeserver gives each of them its own identity: the homeserver attributes an action to the hive that took it, and revoking one hive's standing leaves the others alone. Its access token is the **sender token**. `swarm-controller`, its only minter, mints it for every hive with the swarm's appservice token and publishes it to `swarm/hives//matrix/sender-token`, inside the hive's own read grant (`swarm/hives//*`). Nothing on the hive uses it any more: hive-c0re used to present it for its Space and invite calls and no longer makes any. The name says what it authenticates as — an account the swarm's appservice creates — rather than any privilege level, because it carries none. Promoting a user to homeserver admin and resetting a password both need an admin **sender**: `!admin …` messages into `#admins:`, and tuwunel only treats a message as a command when its sender is already an admin. Of the swarm's own accounts only `@swarm` is a homeserver admin (operators are too, see [Operators are homeserver admins](#operators-are-homeserver-admins)), so both are swarm-level operations.
Appservice identity `swarm-matrix-ctl appservice render` renders the registration from the container's copy of the appservice tokens before tuwunel starts, so every boot has both halves, with the store up or down. - **Access tokens live on the device that minted them.** `login_with_password` stays on, so the password fallback works too. - **The homeserver's `admin_execute` promotes only `@swarm` at boot** (above); a hive's sender account is never promoted. - **The value that matters lives at `swarm/controller/swarm-controller/matrix/appservice-token`.** `appservice sync` writes it there whenever the store's differs from the registration's `as_token`, and `swarm-controller` reads it from there.
Initial rollout settings: - `allow_federation = true` at the protocol level so swarms can be wired up later by extending `trustedServers` without a homeserver restart. `trusted_servers = []` keeps it effectively closed until you list peers. - `allow_registration = false`. tuwunel checks this flag only for requests that arrive **without** an appservice token, so the swarm's appservice still creates accounts and tuwunel refuses everyone else. With no registration token configured, `allow_registration = true` makes tuwunel refuse to start unless `yes_i_am_very_very_sure_…_open_registration_…` is also set. - `allow_encryption` — server-side E2EE switch, sourced from `services.hyperhive.swarm.matrix.allowEncryption` (**default `false`**, opt-in). Off by default because on the swarm's own homeserver the operator already controls the transport; turn it on for encrypted rooms on external / federated homeservers or to keep contents opaque to the homeserver admin. **The agent matrix client always supports decryption regardless of this flag** — it uses the `e2e-encryption` feature of `matrix-sdk` so it can read encrypted rooms it's invited to even when this homeserver doesn't permit room encryption. matrix-sdk stores crypto keys in the per-agent sqlite store under the state dir; they persist across restarts. `read_room` decrypts via `room.messages()` — UTD events surface as `event_type = "m.room.encrypted"` with `body = "[unable to decrypt]"`. The daemon bootstraps cross-signing on the bearer token alone, which works where the homeserver skips re-auth for a first key upload (MSC3967, as tuwunel does). - **Key backup.** `swarm-controller` mints a random recovery passphrase for every matrix account an agent has, at `swarm/agents//matrix-recovery/` in the swarm secret store, and never replaces it. When `hive-matrix-daemon` brings an account up it reads that passphrase: with no backup on the account's homeserver it turns on server-side key backup and secret storage (log line `matrix recovery enabled`), unless the account already has secret storage, which it never replaces (a `WARN` instead). With a backup there it recovers from it (`recovered from the server-side key backup`), which downloads the room keys and signs the new device with the account's existing cross-signing identity. A crypto store lost to `--purge` or to a primary-token reset therefore comes back with its history. With no passphrase stored yet the account comes up without backup and picks it up on the next daemon start. A failure is a `WARN` and never stops the daemon. ## Retired hive-side matrix code Earlier versions of hive-c0re created a private "hive" Matrix Space and a `hive-chat` room, invited every agent to both, kept the hive's sender token on disk and offered `hivectl matrix invite`. All of that is gone: matrix is swarm-level, so the hive no longer talks to the homeserver. The Space, the room and the files `/var/lib/hyperhive/matrix/{access-token,space-room-id,chat-room-id}` are harmless leftovers, so delete them by hand if you like. ## Configuration tuning ```nix services.hyperhive.deploy.matrix = { trustedServers = [ "matrix.org" "example.com" ]; # default: [] maxRequestSize = 20000000; # default: 20 MB }; ``` **`trustedServers`** (default `[]`) — list of peer homeserver names whose signing keys tuwunel fetches and trusts. tuwunel enables federation at the protocol level from first boot (`allow_federation = true`) but trusts no remote homeserver until you list it here. For a closed single-hive deployment the default empty list is correct — add peer hive domains here when connecting hives into a swarm (see [`docs/swarm/`](../swarm/README.md)). **`maxRequestSize`** (default `20_000_000` bytes = 20 MB) — maximum size of a single matrix client request body. Matches the matrix-spec recommendation for media uploads and the upstream tuwunel default. Raise for deployments that need large file transfers; lower for resource-constrained hosts where a 20 MB request is unexpectedly large. ## Assertion rationale `config.assertions` in this module fail eval early rather than ship surprising behaviour: - **`services.hyperhive.swarm.matrix.gatewayHost != ""`** — same footgun as `forge.domain`: empty string renders `.`-shaped garbage in both nginx `server_name` (treated as wildcard catch-all, surprising) and `/etc/hosts` (malformed entry). `null` is the right opt-out shape; a config assertion rejects empty string explicitly. SSO is unconditional, so the three below are requirements of running a homeserver at all rather than of a setting: - **Keep `deploy.matrix.sso.clientSecretFile` set** — it defaults to `/run/hive-matrix-oidc/.secret` wherever the homeserver runs, and `swarm-bao-matrix-oidc` writes the secret there from the swarm secret store under matrix-ctl's leaf. The path is on the host's tmpfs, so every reboot fetches the secret again and it never reaches persistent disk. After a reboot the homeserver doesn't start until the store answers; the store-retry timer then starts it with no manual step. A path outside `/run/hive-matrix-oidc/`, or a null, fails at eval, not at boot: tuwunel reads its identity providers from the config file, so a half-configured one can stop the homeserver from starting outright rather than merely hiding a login button. - **Set `swarm.authelia.url`** — without a provider URL there is nothing to discover against. - **Set `swarm.matrix.gatewayHost != null`** — the SSO callback URL is format-locked to `/_matrix/client/unstable/login/sso/callback/`, and the identity provider needs a public name to redirect the browser to. `server_name`'s own bogus-value guard lives in `hive-network.nix` (`services.hyperhive.domain != null`), not here — see [`docs/networking/network.md`](../networking/network.md). ## fluffychat-web build fixes `pkgs.fluffychat-web` ships from `flutter341.buildFlutterApplication`, which has two upstream gaps for fluffychat's web target: - The dart web-worker entry point (`web/native_executor.dart`) isn't compiled — `buildFlutterApplication` only runs `flutter build web` on the main entry. - `native_imaging`'s C source isn't built — emscripten isn't a flutter-builder native build input. Both fixed in `nix/host-modules/hive-matrix.nix` via two derivations: - **`fluffychat-web-imaging`** builds `Imaging.{js,wasm}` from the `native_imaging` C source via `pkgs.emscripten`. Source comes from `pkgs.fluffychat-web.passthru.pubspecLock.dependencySources.native_imaging` — already in the build closure of the flutter app, so no parallel hash pin and version autosyncs with nixpkgs bumps. Build closure is ~3.6 GiB (emscripten LLVM); runtime closure is just the two output files. `dontConfigure = true` because cmake runs inside `js/Makefile` via `emcmake cmake`, not at the package root. The build script needs `HOME` + `EM_CACHE` writable for emscripten's on-demand sysroot build (libc, libc++ → wasm). - **`fluffychat-web-fixed`** is `pkgs.fluffychat-web` plus a `postInstall` patch that (a) compiles `web/native_executor.dart` via `dart compile js` (dart from the flutter341 closure, no incremental cost) and (b) installs `fluffychat-web-imaging`'s outputs into `$out`. Two subtle details worth knowing before touching either derivation: - **`make -C js`** instead of `cd js; make` — keeps the build-phase pwd at the source root so `installPhase` doesn't have to know about the cd. Robust against future reorders / `dontBuild`. - **`web/native_executor.dart`** as a build-CWD-relative path, *not* `$src/web/...` — `dart`'s `package_config.json` walk-up needs to hit `buildFlutterApplication`'s pub-get output (`.dart_tool/` in the build CWD). Walking up from a read-only `$src/` store path finds no `.dart_tool/` and errors with "Couldn't resolve the package 'matrix'." Drop both derivations when nixpkgs's flutter builder grows worker + emcc support upstream. Mount point is `chat./` (the `gatewayHost` vhost); upstream `--base-href "/"` is correct at sub-domain root, no override.