orca/docs/reference/orcad-operations.md

Running orcad

orcad is the Orca runtime served from plain Node. This is the contract between it and whatever supervises it: what it binds, what it owns on disk, who restarts what, and what its readiness payload actually proves.

Two long-lived processes, not one

A deployment is orcad plus the terminal daemon.

	orcad	terminal daemon
Started by	the supervisor	orcad, detached
Owns	RPC, git, worktrees, persistence	every local PTY
Lifetime	one supervised run	detached from orcad, not its service
Endpoint	ws://<bind>:<port>	<data-root>/daemon/daemon-v<N>.sock

orcad detaches the daemon and calls disconnectDaemon(), never shutdownDaemon(). The built-in remote deployment path stops only the recorded orcad PID, so the daemon and its PTYs survive. The successor adopts the current endpoint and routes supported previous protocol versions through legacy adapters. This makes a PID-scoped update, rollback or restart non-destructive to live work.

Process detachment is not service isolation. A daemon that orcad launches directly, and every PTY it owns, remain in the same systemd service cgroup. KillMode=mixed does not preserve them: it sends the graceful stop signal only to the main process, then sends SIGKILL to every process remaining in the cgroup the moment that main process exits — TimeoutStopSec never gets the chance to apply. KillMode=control-group is destructive too. KillMode=process leaves service-owned processes unmanaged and is not a supported preservation mechanism.

Service-restart survival therefore requires a separately supervised cgroup, and orcad now asks for one: on Linux it launches the daemon through systemd-run --user --scope, which places the daemon and its PTYs in their own transient orca-daemon-<launch-nonce>.scope unit under the user slice instead of the caller's service cgroup. A stop or restart of the service unit then leaves that scope — and the live terminals in it — running, and the successor adopts the endpoint as it always has.

A newly launched private daemon scope also follows the daemon's own lifetime. A small detached shell holds an input pipe from the daemon; after that pipe closes and /proc confirms the daemon PID is gone, it asks the user manager to stop that exact scope. Systemd sends remaining processes SIGTERM and escalates after five seconds. This includes children that double-forked or called setsid and can no longer be found by parent PID. Disconnecting or restarting the runtime does not close the pipe: the daemon owns it.

The cleanup only arms on a fresh scoped launch with a matching launch nonce. Adopted legacy scopes can contain GUI processes and are never armed retroactively. Unscoped launches and children deliberately moved into another systemd unit remain outside this cleanup. nohup, disown, and tmux alone do not move a process out of its cgroup, so those children now end when their terminal daemon dies. Work intended to outlive that daemon needs its own service or scope.

The scope is requested only where it can work. All of these must hold:

• Linux with systemd as PID 1 (/run/systemd/system exists).
• A reachable user bus — a connectable bus socket in the per-UID runtime dir (/run/user/<uid>, or whatever XDG_RUNTIME_DIR points at). For a service account that is not otherwise logged in, that means loginctl enable-linger <user>; a unit whose RuntimeDirectory= hardening moves XDG_RUNTIME_DIR off the per-UID path is handled, because the real per-UID path is probed first.
• systemd-run on PATH and answering --version.

Any of those missing, or a StartTransientUnit call that fails anyway, falls back to the direct launch — and in that unscoped fallback case the paragraph above still describes reality: the daemon shares the service cgroup and a combined-unit stop ends live terminals. Read the cgroupUnit field in the daemon health payload to tell the two cases apart on a running host; it is populated from /proc/self/cgroup, so it reports the isolation the daemon actually has rather than what the launcher intended.

Bind policy

--bind <literal-ip>, default 127.0.0.1.

Only literal IPs are accepted; hostnames are refused because DNS would decide which interface got bound. localhost maps to 127.0.0.1. 0.0.0.0 / :: are the explicit opt-ins to network reach, and the startup log says so on every launch.

The bind is pinned, not defaulted. Two things widen the desktop's listener on their own — orca serve's wide default, and a startup where some device has connected before — and an unattended host's exposure must be exactly what the operator asked for on every launch. A mobile pairing offer, which normally rebinds to all interfaces, is refused while the bind is pinned to loopback and reports network_exposure_failed rather than advertising an endpoint nothing can reach.

Under the shipping design a client reaches a remote orcad over an SSH local port-forward, so loopback is the correct default and the pairing credential travels over SSH.

Data root and the instance lock

The data root is $ORCA_USER_DATA, else $XDG_DATA_HOME/Orca, else ~/.orca.

Before the profile index or the store is touched, orcad takes <data-root>/orcad.lock. It refuses to start when:

Code	Meaning
orcad_data_root_wrong_owner	the root is owned by another uid (POSIX)
orcad_data_root_shared	the root is group/world accessible and could not be tightened
orcad_instance_lock_held	another live orcad owns this root
orcad_instance_lock_foreign_identity	the lock belongs to a different identity
orcad_data_root_unusable	the root cannot be created, stat'd or written

A root that is merely too permissive and that we own is tightened to 0700 rather than refused — orcad stores credentials there unsealed (no OS keyring on this host), so the goal is a private root, and refusing when we could just fix it helps nobody. We refuse when the permissions are not ours to fix. Windows is exempt from the owner and mode checks: ACLs are not expressible as a POSIX mode, and statSync().mode there reports a synthesized one.

A dead holder's record is reclaimed (PID plus process start time, so a recycled PID does not read as alive). A record belonging to a different identity is never reclaimed.

The lock scopes one role — who is the runtime. It deliberately says nothing about the daemon, which lives under <data-root>/daemon and fences its own endpoint with its own PID record. A lock that asked "is any process using this root" would refuse exactly the restarts a live daemon makes worthwhile.

Supervision

Process-scoped and cgroup-wide stops

The built-in remote updater performs a PID-scoped stop and keeps the daemon's install version pinned while it owns sessions. A combined-unit systemd stop or restart is different: unless the daemon holds a durable cgroup scope of its own (see Two long-lived processes, not one), it reaps the daemon and every live terminal after the graceful window. Treat a stop as destructive unless health.terminalDaemon.cgroupUnit names an orca-daemon-*.scope on that host.

Before a cgroup-wide stop, obtain a fresh orca-ide terminal list --json result using the same OS account and home as the daemon. Invoke the installer's absolute launcher path so sudo's secure_path cannot hide a per-user registration (for example, sudo -Hu orca /home/orca/.local/bin/orca-ide terminal list --json). Replace both orca and /home/orca with the service account and home used by the unit; an extracted deployment may use its absolute resources/bin/orca-ide launcher instead. A safe empty census is untruncated, has an explicit hostScope, covers every execution host affected by the stop, and lists no terminals on those hosts. Every omittedHostIds entry must be explicitly accounted for outside the target service's execution boundary. A separately paired runtime is outside that boundary; local execution and SSH hosts reached through this runtime are not. An affected or unknown omission, missing scope, truncation, a failed request or lost contact makes the result unverifiable: defer the stop. Do not admit new work after the census. Orca does not yet provide an atomic census-and-stop fence.

Who supervises orcad

An external supervisor (systemd, launchd, a process manager). orcad conforms to it:

• Readiness. One JSON line on stdout (--json), type: "orca_server_ready", published after the listener is bound and the daemon verdict is in. There is no separate readiness socket; the line is the signal. Set the supervisor's start timeout generously — the daemon launch has its own retries and can take tens of seconds on a cold host.

• Shutdown. SIGTERM or SIGINT starts a graceful stop. A second signal exits immediately with code 1 rather than being swallowed — a supervisor's second signal means its first deadline elapsed, and waiting silently is what turns a stop into a SIGKILL, the one teardown that skips the daemon handoff. orcad also imposes its own 15s deadline and exits 1, so the failure stays attributable instead of arriving as an unlogged kill.

• Exit codes.

  Code	Meaning	Supervisor should
  0	clean shutdown	restart per policy
  1	startup or shutdown failure	restart with backoff
  78	configuration fault (bind address, data root, instance lock)	not restart

  78 is EX_CONFIG. Put it in systemd's RestartPreventExitStatus: restarting on a data root owned by someone else is a restart-spin, not a recovery.

• Logs. orcad writes human-readable diagnostics to stderr and its readiness contract to stdout; the supervisor owns capture and rotation. The daemon, being detached, writes its own NDJSON lifecycle log to <data-root>/logs/daemon.log (suppressed by ORCA_DIAGNOSTICS_DISABLED=1). Rotation of that file is not implemented — see What is not covered.

orcad supervising the daemon

• Launch. On Linux, through systemd-run --user --scope so the daemon gets its own transient cgroup and survives a service-unit restart; everywhere else, and wherever that scope is unavailable, forked detached. Either way it runs daemon-entry.js beside orcad.js with its own PID record, token and socket under <data-root>/daemon.
• Adoption before spawn. A daemon already answering the endpoint is adopted, not replaced, unless it is unhealthy, foreign, or built from a superseded bundle and owns no live sessions. Replacing a healthy daemon kills its PTYs, so code freshness always defers to live work.
• Restart. The adapter respawns the daemon on death, transparently to callers.
• Crash-loop containment. At most 5 launches per 60s rolling window per orcad run; past that, launches are refused with daemon_crash_loop and terminals fail with that message instead of the process forking forever. The window slides, so a repaired host recovers without restarting orcad. An operator-initiated daemon restart clears it — that is the deliberate "try again".
• No macOS login-session watch. That watch retires the daemon when the spawning GUI login session dies. An orcad daemon must survive its SSH session ending.
• Shutdown. orcad never stops the daemon. A daemon that was never adopted retires itself after its adoption window; an adopted one stays resident (see Decommissioning).

Decommissioning

After a PID-scoped stop, an adopted daemon stays resident so the next orcad can reattach. A combined-unit systemd stop also leaves a scope-isolated daemon resident, but kills one that fell back to the service cgroup. To retire a process-scoped deployment, apply the census rule above, stop orcad, then stop the daemon named by health.terminalDaemon.pid. Only report it exited after verification on the execution host; loss of contact is unverifiable.

Health

The readiness payload carries a health object:

buildHash    sha256 (16 hex) of the running orcad bundle — build identity that a version
             string cannot give, so a rollback that did not replace the file is visible
buildVersion ORCA_VERSION
nodeVersion  / nodeAbi   process.versions.node / .modules — the ABI native addons must match
platform / arch / pid
terminalDaemon:
  state              live | degraded | absent
  ownsFreshSessions  whether NEW terminals are daemon-owned; this supports PID-scoped
                     restart recovery, not supervisor or service-cgroup isolation
  pid                the live daemon's pid, from its own PID record
  buildVersion       the build the LIVE daemon was forked from (may legitimately predate
                     this orcad after an update — reporting orcad's version for both would
                     hide exactly that)
  entryPath / protocolVersion
  selfTest { ok, coverage, verdict, durationMs }

What the self-test proves

selfTest runs checkDaemonHealth against the daemon's socket. It is green only when the daemon opened its socket, completed the protocol handshake, and ran ptySpawnHealth — a real short-lived PTY spawned inside the daemon's own process. It therefore spans both processes: orcad drives it, the daemon performs it, the verdict crosses the socket.

• coverage: 'pty-spawn' — the full round trip above.
• coverage: 'handshake' — win32 only, where checkPtySpawnHealth returns without spawning anything. A green verdict there covers the handshake and nothing more. It is reported separately rather than folded into ok so nobody reads it as a PTY round trip.

state is live only when the self-test passed and ownsFreshSessions is true. A daemon that answers but has fallen back to local spawning for new terminals is degraded, because those terminals die with orcad. A daemon that answered and then failed its spawn probe is also degraded, not absent: it still holds live sessions, and calling those exited would be the verdict ssh-execution-boundary.md forbids guessing.

What is not covered

Named here so nothing reads as implemented that is not:

• A continuous health endpoint. health is published once, in the readiness payload. A supervisor's periodic liveness/readiness probe needs an HTTP or RPC surface over the same collectOrcadHealth(); that surface does not exist yet.
• Supervision of an unscoped fallback daemon. When the durable systemd-run --user --scope launch is unavailable (see above) orcad and its daemon share one service cgroup, and a combined-unit stop cannot preserve live terminals. There is no mechanism that re-isolates such a daemon after the fact.
• libc slot. There is no honest health value to publish until native libc detection owns it.
• degradations[]. The readiness contract does not publish this collection yet.
• Credential administration (list / revoke / rotate devices, expiring pending offers, structured security logging).
• Pinned-port fail-closed. A pinned --port still falls back to an OS-assigned port on conflict.
• Reconciling webClientUrl with reachability under the loopback default.
• State-schema rollback rules.
• Daemon log rotation. <data-root>/logs/daemon.log grows unbounded.