Nightly backups to a mounted NAS share ran from May and then stopped, failing
with [Errno 30] Read-only file system. The reporter checked folder permissions
-- correctly: the mount is gid=backup,dir_mode=0775, the service user is in that
group, and his own shell writes to the share fine.
Errno 30 is EROFS. A permission problem is errno 13. EROFS means the filesystem
refused the write, and it refused because we told it to: our systemd unit ships
ProtectSystem=strict, which mounts everything read-only inside the service's
mount namespace and carves back out only ReadWritePaths=<install> <data> <logs>.
A NAS share is not one of those three. Reads are unaffected -- which is why the
UI happily listed his existing backups from the share while being unable to
write a new one -- and his shell is outside the namespace entirely, so every
check he could think to run said the directory was fine.
Both installers write the unit file wholesale, so a ReadWritePaths line added by
hand disappeared on the next install, taking the backups with it. They now back
the old unit up (.bak-<timestamp>) and carry the operator's extra writable paths
forward, reporting which ones they kept. The unit template documents the
carve-out.
The output directory is probed with a real write when it is saved and when the
backup card loads, so an unwritable path is caught there rather than at 03:00
for a week. On failure the card names the cause and hands over the fix with the
operator's path already in it (systemctl edit bambuddy -> ReadWritePaths=...),
and a failed run reports the same diagnosis rather than the raw OSError. EROFS
outside systemd, permission-denied, out-of-space, not-a-directory and missing are
told apart, in all 11 locales.
Docker: a backup path that is not bind-mounted is writable -- the write lands in
the container's ephemeral layer and is lost on the next compose up. The probe
compares the directory's device against the container root and warns, with the
compose snippet that mounts it properly.
A Shelly reports one energy figure — aenergy.total, a lifetime counter in Wh
that never resets. Bambuddy had a single REST energy field and filed whatever
it found under "today", so the value never reset at midnight, and Yesterday
and Total stayed at zero: get_energy() simply never set those keys.
With `total` unpopulated, the hourly snapshot recorder skipped the plug, so
the Statistics page's energy figure was zero as well, not just the Settings
card.
Split the REST energy config in two: rest_energy_path still means "used
today", rest_energy_total_path means "lifetime counter". A Shelly has only
the latter; a Tasmota behind a REST bridge has both; sharing a URL costs one
fetch, not two.
Then derive Today and Yesterday from that counter using the snapshots we were
already taking: today = counter now - counter at the last local midnight;
yesterday = the gap between the two previous midnights. Local midnight, not
UTC — a UTC boundary rolls Today over at 02:00 in Berlin. The snapshot loop
now ticks on the local hour so a reading lands on the boundary instead of up
to an hour early. A counter that goes backwards (factory reset) reports
nothing rather than a negative.
Collateral, found while verifying on both engines: the smart-plug DateTime
columns are naive UTC but the code wrote aware datetimes into them. SQLite
drops the offset; asyncpg raises DataError. So on Postgres every snapshot
capture raised inside the loop's except, and every status poll raised on
last_checked — the whole subsystem was dead on the database we recommend for
multi-printer installs. All plug timestamps are naive UTC now.
Existing REST users with a cumulative path in the today field must move it to
the new lifetime field; the form and wiki now name which counter each wants.
The Windows installer's embedded Python doesn't carry an IANA tz
database, and the stdlib zoneinfo has no system DB to read on Windows.
ZoneInfo("UTC") raises ZoneInfoNotFoundError on those installs, and
the new /api/local-backup/status endpoint 500s on the resulting
uncaught exception. Surfaced via a Windows traceback from a user's log:
File "...\backend\app\services\local_backup.py", line 32, in _local_zone
return ZoneInfo("UTC")
zoneinfo._common.ZoneInfoNotFoundError: 'No time zone found with key UTC'
_local_zone()'s try/except only covered the TZ-env branch — both
fallbacks unconditionally called ZoneInfo("UTC") and re-raised.
Fix (two parts):
1. services/local_backup.py — return type widened from ZoneInfo to
tzinfo, the UTC fallback is wrapped in its own try, and the
last-resort fallback returns datetime.timezone.utc (stdlib, no
IANA DB needed). str(timezone.utc) == "UTC" so the response shape
on /api/local-backup/status is unchanged. The astimezone call in
_calculate_next_run accepts any tzinfo — no other call sites
affected.
2. requirements.txt — pin tzdata>=2024.1; sys_platform == "win32" so
the next Windows installer build ships the IANA DB, and any non-
UTC TZ value (e.g. Europe/Berlin) resolves correctly. The stdlib
fallback can only ever give UTC. Linux/macOS unaffected by the
platform marker — they already have the system tz database.
The Scheduled Local Backups time-of-day picker was interpreted as UTC by
_calculate_next_run, so a UTC+3 user had to enter 18:00 to get a 21:00
local backup. The UI labeled the field "UTC" but it was still surprising.
Picker is now interpreted in the container's local timezone, resolved
from the TZ env var via zoneinfo.ZoneInfo (same source the Support page's
environment.timezone shows). UTC fallback when TZ is unset or
unrecognised. The /local-backup/status endpoint exposes the resolved
zone, and the UI renders it next to the field via a new
backup.localTimeHint i18n key with real translations in all 10
non-English locales.
One-time behaviour change for users who entered a UTC time as a
workaround: the first scheduled cycle after upgrade will run at their
local TZ offset earlier than expected. Re-enter the time as local once
and it is correct from then on. No migration is shipped; migrating
around a DST boundary would be ambiguous.
maziggy