reseed_if_terminal created its temp as <auth>.rebootstrap.<pid>.tmp with
O_CREAT|O_EXCL. Boot-hook PIDs inside a container are near-deterministic,
so a run SIGKILL'd between create and replace leaves a same-named file and
every later boot hits FileExistsError - which main() swallows as
"error (ignored)", leaving the terminal-session recovery path dead until
someone deletes the temp by hand.
tempfile.mkstemp in the auth dir gives a random name at 0600 (stdlib only,
matching the script's no-hermes-imports rule); the fsync + os.replace +
unlink-on-failure semantics are unchanged.
Ten hand-rolled "write a token file safely" routines each carried a
different subset of {0600-on-create, fsync, atomic_replace, parent-0700
guard, BaseException cleanup}. Two of them (iron_proxy state files,
the exchanged-JWT store) still opened the temp file at process umask
and chmod'ed afterwards - the exact TOCTOU window the others document
as fixed. None of the bare-os.replace copies got atomic_replace's
Windows-contention retry or EXDEV fallback.
utils gains fsync_dir= (absorbs auth.py's dir fsync), atomic_write_bytes
(vault blob) and mode= on atomic_write_text; the ten sites become 1-3
line callers. mkstemp creates the temp file O_EXCL at 0600 regardless of
umask, so the payload is never umask-readable.
Behavior change: iron_proxy proxy.yaml/mappings.json and the exchanged-JWT
store are now 0600 from creation and fsync'd; every credential write goes
through atomic_replace (symlink-preserving, Windows retry, EXDEV copy).
auth_nous shared store now uses atomic_replace too (it forced os.replace
with no recorded reason). secret_sources cache parent-0700 goes through
the guarded secure_parent_dir instead of an unguarded chmod.
The stage2-hook auth.json seed is first-boot-only ([ ! -f auth.json ]) to avoid
clobbering rotated refresh tokens on restart. That guard means a container whose
Nous bootstrap session took a terminal invalid_grant (tokens cleared,
providers.nous.last_auth_error.relogin_required stamped) cannot recover from a
restart — it stays unauthenticated until the credential is replaced.
Add a self-heal path: an orchestrator that manages the container supplies a
freshly-issued session via HERMES_AUTH_JSON_REBOOTSTRAP (distinct from the
create-only *_BOOTSTRAP var). On boot, scripts/docker_rebootstrap_nous_session.py
swaps ONLY the providers.nous entry, and ONLY when the on-disk entry is provably
terminal (quarantine marker + no usable tokens). Healthy/rotating/absent/
unparseable auth.json is always a no-op, so the env is safe to leave set across
restarts and never clobbers a good token. Pure stdlib, runs as its own
subprocess, always exits 0 so a re-seed error never fails the boot.
Reuses the same terminal predicate as get_nous_session_validity() so we re-seed
only a session that is genuinely dead.
