Miguel Palhas
aa34d975a9
The test named for recovery only read the sidecar back; nothing covered the id reaching the recovered session, which is what a resume reads. Also narrows RESTART.md's leniency claim: the custom Deserialize lives in the client's own binary, so an older build still fails on Dormant.
108 lines
5.9 KiB
Markdown
108 lines
5.9 KiB
Markdown
# Restart and upgrade contract
|
|
|
|
Maestro is upgraded in place: the operator reinstalls the binary and systemd
|
|
restarts the daemon under every browser tab and TUI that is attached to it.
|
|
tmux keeps the sessions alive across that (see `docs/INSTALL.md`), but clients
|
|
lose their sockets. This document is the contract for what a client does about
|
|
it — what the daemon publishes, how a client tells a restart from a blip, and
|
|
what the user sees while it happens.
|
|
|
|
## What the daemon publishes
|
|
|
|
`GET /api/info` carries two fields beyond identity and presets:
|
|
|
|
| field | meaning |
|
|
| ---------- | -------------------------------------------------------------- |
|
|
| `build` | `{ commit, commit_date, dirty }` — the commit the binary was compiled from |
|
|
| `instance` | uuid regenerated on every daemon start |
|
|
|
|
`build` is stamped at compile time by `crates/maestro-daemon/build.rs`, which
|
|
runs `git` in the checkout it is compiled in. The Nix build has no `.git` in the
|
|
crane-filtered source tree, so `flake.nix` passes the flake's own revision as
|
|
`MAESTRO_BUILD_COMMIT` / `MAESTRO_BUILD_DATE` / `MAESTRO_BUILD_DIRTY`. A build
|
|
with neither source reports empty strings — clients render that as
|
|
"unknown release" and fall back to `instance` alone.
|
|
|
|
`instance` is the one that never goes missing. It says *this process*, so two
|
|
replies that differ on it are two runs of the daemon, even when the commit did
|
|
not change (a plain `systemctl restart`, or a crash).
|
|
|
|
## How a client reads them
|
|
|
|
Three verdicts, from comparing the reply before an outage with the one after
|
|
(`compareIdentity` in `web/src/daemonLink.ts`, mirrored by
|
|
`crates/maestro-tui/src/daemon_link.rs`):
|
|
|
|
- **upgraded** — both commits are known and differ. New server code.
|
|
- **restarted** — commits match (or are unknown) and `instance` differs.
|
|
- **same** — neither changed; the socket blipped, the daemon never moved.
|
|
|
|
Only *upgraded* is special. A browser tab is holding a bundle that the upgraded
|
|
daemon no longer serves, so it reloads the page rather than driving new server
|
|
code from an old bundle. The TUI is its own binary — a reload would not replace
|
|
it — so it stays up, reconnects, and says which release it is now talking to;
|
|
the user restarts `maestro tui` when they want the new client.
|
|
|
|
## What the user sees
|
|
|
|
The **status indicator** lives in the sidebar footer, left of the spawn button,
|
|
in both clients. Its colour is the link state, and it names the running release
|
|
— commit hash and commit date — on hover (web) or in the status bar (TUI).
|
|
|
|
| state | colour | meaning |
|
|
| -------------- | ------ | ---------------------------------------------------- |
|
|
| `connecting` | amber | first probe hasn't landed |
|
|
| `online` | green | daemon answered; same process, or a resolved new one |
|
|
| `reconnecting` | amber | socket dropped, still inside the grace window |
|
|
| `down` | red | unreachable past the grace window — the UI blocks |
|
|
| `updating` | red | answered on a new commit; the page is reloading |
|
|
|
|
`updating` is web-only, because reloading is web-only. The TUI goes straight
|
|
back to `online` after an upgrade and puts `updated: <hash> (restart tui)` on
|
|
its status bar instead, until the user restarts it.
|
|
|
|
The **restart overlay** is up for exactly `down` and `updating`. It is not
|
|
dismissable and it swallows the app's keyboard shortcuts: everything behind it
|
|
would act on a daemon that is not there. In the TUI the quit binding still
|
|
resolves, so a blocked client is never a trapped one. It clears itself the
|
|
moment a probe succeeds — there is no "retry" button, because the client is
|
|
already retrying.
|
|
|
|
## What survives, and what comes back dormant
|
|
|
|
A daemon restart leaves tmux alone, so recovery re-adopts every
|
|
`maestro-<uuid>` session tmux still holds and the operator sees no change
|
|
beyond the reconnect above.
|
|
|
|
A **host reboot** is different: it kills the tmux server, so there is nothing
|
|
to adopt while every session's sidecar is still on disk. Recovery makes a
|
|
second pass over those sidecars and registers each as a `Dormant` session
|
|
(#162) — id, name, cwd, command, worktree and `created_at` intact. A dormant
|
|
session has no pane and no PTY bridge: it cannot be attached to, typed into or
|
|
resized, and neither watcher pass touches it. It is a record of what was
|
|
running, and the only thing left to do with one is dismiss it, which removes
|
|
the sidecar so the next recovery does not bring it back.
|
|
|
|
`SessionStatus` is a wire type, so from this build forward it deserializes
|
|
leniently on both clients: a spelling the client does not know reads as `Dead`
|
|
rather than failing the whole session. That leniency lives in the client's own
|
|
binary, so it covers spellings added *after* this build, not this one — a CLI
|
|
or TUI still running an older build fails to parse a `Dormant` session, and
|
|
with it the whole session list, until it is upgraded. Clients render a dormant session as known-but-not-running —
|
|
see `docs/SIDEBAR.md` for the card and `docs/COMMAND-BAR.md` for how it ranks.
|
|
|
|
## Timing
|
|
|
|
- **Grace window** — 1200 ms between the socket dropping and the overlay
|
|
appearing. A wifi hiccup or a laptop waking up should not throw a modal.
|
|
- **Poll cadence** — `GET /api/info` every 700 ms while unreachable, flat, not
|
|
backed off: a restart takes a second or two and the point is to unlock as soon
|
|
as it is over. The events socket keeps its own exponential backoff for the
|
|
session stream; the two are independent, and the probe is what decides state.
|
|
|
|
The events socket dropping is the trigger, not a timer: the daemon cannot warn
|
|
anyone it is about to die, so its socket closing is the earliest signal there
|
|
is. A reconnect of that socket does **not** by itself clear the state — only a
|
|
probe does, because the socket carries no identity and reconnecting to an
|
|
upgraded daemon must reload rather than resume.
|