`RemoteBackend` existed from the first release and bought nothing it was
designed for. Seven files in `dr-ui` constructed a `NextcloudBackend`
directly, an account *was* a server URL beside a DAV user id, the local
cache directory was named after a hostname, and the launch screen knew
that signing in meant a browser handshake. The trait was real; the seam
was documentation.
A trait over operations is only a quarter of it. Pluggable storage needs
four things, and this adds the other three:
- **Capabilities** — already there, and the reason the engine can drive
two backends at the speed each actually runs at.
- **Configuration** — `dr_sync::Account`: where a library lives, in
whatever form its connector addresses, with no server in it. Loads
every existing config unchanged (`backend` defaults to `nextcloud`,
`endpoint` is stored under its historical `server` key), and
`Account::namespace()` reproduces the old catalog directory byte for
byte, because changing it would abandon a catalog, its thumbnail
shards, and the sidecars holding unsynced offline work.
- **Registration** — `BackendProvider` and `BackendRegistry`.
`ui/dr-ui/src/remote.rs` is now the only file above `dr-sync` that
names a connector.
`Connection` (an account plus an optional `Secret`) replaces the
credentials-and-user-id pair that was threaded through fifteen
signatures in an order that could be swapped. `Secret`'s inner string is
reachable only through `expose()` and its `Debug` prints `Secret(***)`,
so the indirect leak — a `{:?}` on anything holding one — no longer
compiles into a leak.
Nextcloud is unchanged and keeps every peculiarity: propagating ETags,
chunked upload v2, `oc:fileid`, the `oc:permissions` probe on a refused
PUT, the 423 retry classification, Login Flow v2. Those are what the
capability model exists to serve, not something to hide.
`dr-sync-folder` is the second connector: a local disk, a network mount,
an external drive, or a folder a Nextcloud client already syncs. No
account, no credential — the route that works where no secrets daemon
does. It declares `LocalEtags` rather than claiming propagation a POSIX
directory cannot provide, which costs nothing because 50k `stat` calls
are not 50k PROPFINDs. Identity is a path hash, not an inode: an inode
survives a rename but differs between devices and is reused after a
delete, so two machines would disagree about which photograph a
thumbnail belonged to. Re-deriving a thumbnail is a cost; showing the
wrong one is a bug.
docs/storage.md is the contract — the traits, the four steps to add a
backend, and what each connector declares. ARCH §8.0 and §8.4a, and
FR-NC-13, say why.
Library setup as the user described it: pick a folder, choose which RAW
types to look for, scan recursively.
dr-types::FormatFilter the tick-box selection, seeing through VFS
placeholder suffixes so a dehydrated CR2 still
matches as a CR2
dr-sync::scan recursive walk, Depth:1 per directory, pruning
unchanged subtrees where the backend propagates
directory ETags
Verified against nextcloud.tourolle.paris (34.0.2) on a real library:
browse root 32 entries, 98ms
scan PhotosRaw 17,185 RAW files in 334 directories, 34.1s
(7,836 CR2 + 9,349 DNG)
range read 262KB of a 21.5MB DNG in 119ms — 1.22% of the file,
and enough to read "Canon EOS 6D | ISO 100"
That last line is assumption A3 validated on real data. Cataloguing this
library by whole-file fetch would move roughly 370GB; the range path
moves a few MB.
Pruning is capability-gated rather than assumed: with per-entry ETags a
probe costs a request and proves nothing about children, so it is skipped
entirely. A test asserts zero probes in that case.
Still unresolved: /core/preview returns 400 for every parameter
combination tried, including on a JPEG the server reports as having a
preview. Not a request-shape bug — it fails identically bare. Recorded
rather than worked around; ARCH §6.7 already treats server previews as
opportunistic, so nothing depends on it.
Ports JellyTau's traceability tooling to Rust, carrying across the bug it
was repaired for. That gate divided a traced count by frozen literal
denominators; the requirements file outgrew them and it reported 158%
coverage, so it could never fail its own threshold.
Two rules, both enforced by the extractor's own tests:
- denominators parsed from docs/requirements.md at run time
- coverage is |traced ∩ defined| / |defined|, never a raw traced count
The gate additionally fails hard on a misconfigured run — zero
requirements parsed or zero files scanned — rather than reporting a
plausible 0%, and on any orphan tag naming a requirement that does not
exist.
Adapted for DarkRoom: IDs are FR-CAT-1 / NFR-P13 / FR-DEV-3a shapes
rather than JellyTau's fixed three digits, and decisions (D), spikes (S),
milestone items (M) and test ids remain taggable while being excluded
from the denominator — counting them inflated it by 25.
Also adds dr-sync: the RemoteBackend trait and capability model, so the
Nextcloud connector is one implementation rather than the only shape the
engine understands. No mature Nextcloud crate exists (reqwest_dav is too
thin), so the connector will be hand-rolled over reqwest per D7.
Gitea workflows follow the same style: containerised, commented with the
reasoning, desktop and Android on every push, plus a CI check that no
core/ crate depends on the UI toolkit (ARCH §6.5a).
Coverage today: 13.3% (19/143). 50 tests passing.
dtourolle