hyperhive/docs/gateway.md
atlas 24775845a3 nix/hive-gateway: static not-found + unreachable pages for /agent/<name>/ (#755)
mara on #755: "e.g. /agent/name should show an error page stating
that the agent could not be found if missing in json or that it is
not reachable if we get a connection error. we dont want a fully
generic fallback, only for routes already special cased in the
nginx config."

Adds two static HTML pages built at deploy time via
`pkgs.runCommand "hyperhive-agent-error-pages"`:

- **not-found.html** — served when `/agent/<unknown>/...` hits the
  bare `/agent/` catch-all. The catch-all `return 404`s, and
  `error_page 404 = /__hive_agent_not_found` rewrites to the static
  page.
- **unreachable.html** — served when `/agent/<known>/...` proxy_pass
  to the harness returns 502 / 503 / 504. `proxy_intercept_errors
  on` + `error_page 502 503 504 = /__hive_agent_unreachable` on each
  per-agent location block rewrites to the static page.

Mechanics:

- `agentErrorPagesDir` (in the `let` block) is a `runCommand` that
  emits two HTML files using a `<<EOF` heredoc — no template engine
  needed.
- Two `internal` nginx locations (`= /__hive_agent_not_found`,
  `= /__hive_agent_unreachable`) `alias` the exact files. `internal`
  keeps the URIs unreachable from direct operator request — only
  nginx's own error-handling can hit them.
- Per-agent location blocks pick up the `error_page` directive
  through the existing `lib.mapAttrs'` over `agentPortsTable`. No
  per-agent generated content; same static page for all.
- `/agent/` catch-all generates from a tiny optionalAttrs alongside
  the per-agent block — both are no-op when the agent table is
  empty (matches the pre-#15 shape).

Pages: minimal inline CSS, catppuccin palette matching the
dashboard (`#1e1e2e` bg, `#cdd6f4` text, `#cba6f7` not-found heading,
`#f9e2af` unreachable heading). No frontend-dist dependency — render
even when hive-c0re is down. Both link back to `/`.

Per mara's "only for routes already special cased" — scope stays
narrow. Forge / matrix / fluffychat keep nginx defaults; extending
the custom-error pattern to other vhosts is a separate follow-up
if/when needed.

Verified:
- nginx location attrset has `["/", "/agent/", "= /__hive_agent_not_found", "= /__hive_agent_unreachable"]`
- container toplevel builds clean (`nixos-system-hive-gateway-26.05pre-git`)
- `docs/gateway.md::Per-agent error pages` section captures the
  design + rationale + intentional narrowness

Closes #755.
2026-05-31 15:04:54 +02:00

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9.5 KiB
Markdown

# hive-gateway
Single nginx in front of every hyperhive web surface. Container `hive-gateway`, shared host netns, system-config (not meta-flake managed). Configured via `services.hyperhive.gateway.*` + per-subsystem opt-in flags in `services.hyperhive.{forge,matrix,...}`.
## Vhost map
| URL | vhost | upstream | source |
| --- | --- | --- | --- |
| `<hive>/` | `_` (catch-all) | hive-c0re dashboard (`7000`) | always |
| `<hive>/agent/<name>/` | `_` | per-agent harness on `agent_web_port(name)` | `agentPortsFile` JSON, #15 |
| `<hive>/.well-known/matrix/{client,server}` | `_` | inline JSON (no upstream) | `matrix.enable && domain != null`, #660 / #747 |
| `<hive>/matrix/` (deprecated) | `_` | 301 → `matrix.<hive>/` | `matrix.gui.enable`, #772 |
| `forge.<hive>/` | `forge.<hive>` | forgejo (`3000`) | `forge.behindGateway`, #754 |
| `matrix.<hive>/_matrix/*` | `matrix.<hive>` | tuwunel (`8008`) | `matrix.gatewayHost != null`, #764 |
| `matrix.<hive>/` | `matrix.<hive>` | fluffychat-web static | `matrix.gui.enable`, #772 |
| `matrix.<hive>/config.json` | `matrix.<hive>` | inline JSON (FluffyChat boot config) | `matrix.gui.enable && domain != null`, #736 |
Per-agent UIs stay sub-path because they're hyperhive-internal and base-path-aware (iris #731). External standard apps (forge / matrix) get sub-domains because their defaults work cleanly at sub-domain root + per-origin cookies / storage isolation matters.
## Discovery flow (matrix)
Operator points client at `<hive>`. Sequence:
1. Client fetches `http://<hive>/.well-known/matrix/client``{"m.homeserver":{"base_url":"http://matrix.<hive>"}}` (no port suffix when gateway listens on 80).
2. Client connects to `matrix.<hive>/_matrix/client/...`.
3. Gateway routes `/_matrix/*` → tuwunel at `127.0.0.1:8008`.
Federation peers fetch `.well-known/matrix/server``{"m.server":"matrix.<hive>"}` and connect to `matrix.<hive>:8448` per spec default. Gateway only listens on configured `port`; cross-hive federation needs either an SRV record (`_matrix._tcp.matrix.<hive>` → port 80) OR `matrix.openFirewall = true` so peers reach tuwunel's federation port directly. Hyperhive is mostly closed/internal, so this rarely bites.
## SPA fallback (Accept-header pattern)
The `<hive>` catch-all and the `matrix.<hive>` vhost both serve a flutter SPA (per-agent UI, fluffychat). Two requirements collide:
- hard-refresh on a sub-route must serve `index.html` (SPA's client-side router takes over after JS bootstrap)
- missing assets must surface as 404, not as HTML with wrong content-type (the original #643 bug)
Solution: an `nginx http`-context `map $http_accept $matrix_spa_target { ... }` keyed on the request's Accept header. Browser navigations (`Accept: text/html,...`) get `index.html`; asset fetches (`Accept: image/*`, `*/*`, etc.) get a sentinel nonexistent path → `try_files` falls through to `=404`. No extension allowlist, no `if` block, no regex heuristics. #686 + #729 thread for the design history.
## Local dev (`localHostsEntry`)
`services.hyperhive.gateway.localHostsEntry = true` adds entries to the host's `/etc/hosts`:
- `<hive-domain>``127.0.0.1`
- `forge.<hive>``127.0.0.1` (when forge.behindGateway)
- `matrix.<hive>``127.0.0.1` (when matrix.gatewayHost set)
`lib.unique` de-dupes if any sub-domain happens to equal another entry. Operators with real DNS leave it off.
## Sub-domain shape (rationale)
mara verdict at #749:9609 + #747:9722: sub-domain over sub-path for forge + matrix, sub-path for per-agent UIs.
- forgejo's default `ROOT_URL = http://<host>/` works without any `X-Forwarded-Prefix` gymnastics — sub-domain hosting is the canonical Forgejo deploy shape.
- matrix-spec deployments universally use `matrix.<server_name>` for the actual API listener — federation already expects this.
- per-agent UIs are hyperhive-internal; iris's #731 made them base-path-aware specifically for `/agent/<name>/`. Sub-domain per agent would multiply DNS + TLS-per-subdomain cost without per-app config wins.
- cookie / storage isolation: a future forge XSS can't reach the dashboard session because they're different origins.
`services.hyperhive.{forge.domain,matrix.gatewayHost}` take the full hostname (`forge.darkest.space`, `git.example.com`) rather than a label that gets concatenated with hive-domain — mara on #754:9684 wanted operator control over the full shape, not a forced `<label>.<hive-domain>` pattern.
## Tuning knobs
Per-vhost timeouts + body-size limits live in the location blocks:
- forge `/` (forgejo): `client_max_body_size 1G` (LFS), `proxy_read_timeout 1h` (multi-GB clones), `proxyWebsockets = true` (live-update endpoints).
- matrix `/_matrix/` (tuwunel): `client_max_body_size 50M` (media uploads), `proxy_read_timeout 1h` (long-poll `/sync`), CORS `*` (federation + cross-origin clients), `proxyWebsockets = true`.
- per-agent `/agent/<name>/`: `proxy_read_timeout 1d` (long-lived SSE / WebSocket dashboards), `proxyWebsockets = true`, `X-Forwarded-Prefix` set so the harness can build absolute URLs when relative isn't enough.
SSH for forge stays direct on `cfg.sshPort` — separate listener protocol, not HTTP-over-nginx.
## Sequencing history
- #15 v0 (per-agent routing, #740) — first sub-app behind the gateway, JSON port table from c0re.
- #686 / #729 — Accept-header SPA fallback pattern.
- #749 / #754 — forge to sub-domain (mara: sub-domain over sub-path).
- #747 / #764 — matrix sub-domain vhost + `.well-known` delegation.
- #772 / #775 — fluffychat hops from `<hive>/matrix/` to `matrix.<hive>/`.
Next-up tracked separately: #14 (container netns isolation), TLS (#594).
## Firewall posture (host-level)
`hive-c0re.nix` opens the per-agent web-port range
`8100..8999` in the host firewall **only when
`services.hyperhive.gateway.enable = false`**. With the gateway on
(default), it's the sole external entry point and proxies to
`127.0.0.1:<port>` internally — leaving the per-agent ports
firewall-open would defeat the single-front-door story (closes
#621).
Manager hashes into the same range since #753 (no more
"manager pinned at 8000" special case), so one range opening covers
every container.
The dashboard port (`cfg.dashboardPort`, default 7000) is *not*
listed in either case — since #652 it binds `127.0.0.1` only, so a
firewall hole would be a no-op. Remote dashboard access flows
through the gateway. Operators who opt out of the gateway lose
external dashboard reach by design — the surface is privileged
(approve / deny / destroy) and must not be exposed without a real
reverse proxy in front.
## `HIVE_FORGE_URL`: loopback for in-cluster, sub-domain for the operator
Agents poll `HIVE_FORGE_URL` for Forgejo notifications + run all
`hive-forge` calls against it. `hive-c0re.nix` pins this to
`http://127.0.0.1:<forge.httpPort>` for the in-cluster path: every
agent container shares the host's network namespace, so loopback
reaches the forge container directly with no DNS lookup needed
(closes #761).
The post-#754 sub-domain default (`forge.<hive-domain>`) is for
**operator browsers + cross-host clients**, not in-cluster traffic.
Using the sub-domain URL inside agent containers would fail every
`hive-forge` invocation with "Name or service not known" — the
agent's nspawn doesn't have DNS for the external hostname.
## hive-forge container shape
Private Forgejo wrapped in a nixos-container (`hive-forge`, not
`h-*` — keeps c0re's lifecycle scanner out of the picture; the
operator manages it via the standard `nixos-container` CLI). The
container also keeps hive-forge from fighting any `services.forgejo`
the operator already runs on the host — separate systemd namespace,
separate state dir, separate port unless the operator deliberately
collides.
Container shares the host network namespace
(`privateNetwork = false`) so agents reach the forge at
`http://localhost:<httpPort>` without extra plumbing — nixos-container
is here for state + systemd-unit isolation, not network isolation.
State lives at `/var/lib/nixos-containers/hive-forge/var/lib/forgejo/`
and survives container restart / host reboot. To wipe, destroy the
container.
## Per-agent error pages
`/agent/<name>/` requests hit two failure modes; both get static
HTML pages instead of nginx's default error chrome (#755):
- **Agent not found** (`/agent/<unknown>/...`) — name isn't in
`agentPortsTable`. nginx's prefix match falls back to the bare
`/agent/` catch-all, which `return 404`s and `error_page 404` rewrites
to `/__hive_agent_not_found` → serves `not-found.html` with a link
back to the dashboard.
- **Agent unreachable** (`502 / 503 / 504` from `proxy_pass`) — the
per-agent harness isn't responding (container restarting, crash
recovery, etc.). `proxy_intercept_errors on` + `error_page 502 503
504 = /__hive_agent_unreachable` rewrites to `unreachable.html`.
Both pages are built at deploy time via `pkgs.runCommand` (one nix
derivation `hyperhive-agent-error-pages` with `not-found.html` +
`unreachable.html` inside) and served via two `internal` nginx
locations with `alias` to the exact file. `internal` keeps the
files from being directly request-able by operators — only nginx's
own error-handling can reach them.
Page styling: minimal inline CSS matching the dashboard's catppuccin
palette (`#1e1e2e` bg, `#cdd6f4` text, `#cba6f7` heading). No
dependencies on the frontend dist — these pages render even when
hive-c0re itself is down.
Scope is intentionally narrow per mara on #755: "only for routes
already special cased in the nginx config". Other gateway routes
(forge / matrix / fluffychat) get nginx defaults — extending the
custom-error pattern there is a separate follow-up.