647b19cf4a
storageSnapshotSourcePath resolved a snapshot's source path with
engineSnapshotsJson "$idx" "$snapshot_id"
but that function's second parameter is an app TAG filter. So it ran
`restic snapshots --tag app=<snapshot-id>`, matched nothing, and returned 1 —
every time, for every snapshot, since the file was written.
Nothing broke loudly, because both callers have a fallback:
* storageRestoreAppTo fell through to "restoring in place", reinstating the
exact cross-root bug the file exists to fix — restoring onto a host whose
containers root differs from the source's matched no include path and
restored nothing, silently
* the first-run preflight never read a manifest, so every app reported size
"?" and its fit and location checks passed unconditionally. Thirteen green
ticks that had checked nothing.
Add engineSnapshotPaths: restic answers it with a positional snapshot id, kopia
by filtering its list. borg has no adapter on purpose — it rebuilds its listing
from archive metadata that carries no paths — so a missing adapter is a quiet
"no" and those callers keep their in-place fallback.
Add scripts/dev/lp-preflight-test, which pins the cases that must say NO: an
app too big for the disk, one this version no longer ships, one whose storage
location is gone, and a resolver that reaches for the app-tag filter again.
Verified against both historical bugs — reintroducing either fails the test.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
98 lines
3.7 KiB
Bash
98 lines
3.7 KiB
Bash
#!/bin/bash
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# Resolving where a snapshot's data actually lives, and where it should land.
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#
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# The bug this exists to fix predates storage locations. Restore did:
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#
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# engineRestoreSnapshot "$idx" "$id" "/" "$containers_dir$app"
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#
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# — restore to / with an include filter built from the LOCAL containers root.
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# restic reproduces a snapshot's absolute paths, so that only works when source
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# and destination paths are byte-identical. LibrePortal has shipped three
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# configurable roots for a while, so migrating from a host installed with
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# --containers-dir=/mnt/ssd/apps onto a default host matched no include path and
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# restored NOTHING, silently. Storage locations make that ordinary rather than
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# rare.
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#
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# The fix is to take the source path from the SNAPSHOT rather than from local
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# config, and to stage-and-move whenever it differs from where the app belongs
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# here.
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# The path an app occupied in a snapshot. restic records the backed-up paths on
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# the snapshot itself, so ask the repository rather than guessing.
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storageSnapshotSourcePath()
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{
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local idx="$1" snapshot_id="$2" app="$3"
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local path
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# Ask about this ONE snapshot. The first version passed the id to
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# engineSnapshotsJson, whose second parameter is an app TAG filter — so it
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# searched for `--tag app=<snapshot-id>`, matched nothing, and returned 1
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# every single time. Nothing broke loudly, because both callers have a
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# fallback: storageRestoreAppTo restored in place (reinstating the
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# cross-root bug this file was written to fix) and the restore preflight
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# reported every app's size as "?" while its fit and location checks passed
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# unconditionally.
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path=$(engineSnapshotPaths "$idx" "$snapshot_id" 2>/dev/null \
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| grep -E "/${app}(/|$)" | head -1)
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[[ -n "$path" ]] || return 1
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printf '%s' "${path%/}"
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}
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# Restore an app from a snapshot to wherever it belongs on THIS host.
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#
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# Same path on both sides -> restore in place, exactly as before.
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# Different -> restore into staging, then move the tree into position. The move
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# goes through the root helper because the restored tree carries container
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# sub-UIDs the manager cannot handle.
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storageRestoreAppTo()
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{
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local idx="$1" snapshot_id="$2" app="$3"
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local dest
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if ! dest=$(appDir "$app"); then
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isError "Cannot restore $app — its storage location is not mounted."
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return 1
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fi
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local src
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if ! src=$(storageSnapshotSourcePath "$idx" "$snapshot_id" "$app"); then
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# Older snapshot, or an engine that does not report paths: fall back to
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# the historical behaviour rather than refusing.
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isNotice "Snapshot does not report its source path — restoring in place."
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engineRestoreSnapshot "$idx" "$snapshot_id" "/" "$dest"
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return $?
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fi
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if [[ "${src%/}" == "${dest%/}" ]]; then
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engineRestoreSnapshot "$idx" "$snapshot_id" "/" "$src"
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return $?
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fi
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isNotice "This snapshot was taken at '$src'; restoring to '$dest'."
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local stage="${restore_dir%/}/relocate-$app.$$"
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runInstallOp mkdir -p "$stage"
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if ! engineRestoreSnapshot "$idx" "$snapshot_id" "$stage" "$src"; then
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isError "Restore into staging failed."
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runInstallOp rm -rf "$stage"
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return 1
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fi
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# restic reproduces the full absolute path beneath --target.
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local staged="$stage/${src#/}"
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if [[ ! -d "$staged" ]]; then
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isError "Restored tree not found at '$staged' — leaving staging in place for inspection."
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return 1
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fi
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if ! runOwnership app-adopt "$app" "$staged" "${dest%/*}"; then
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isError "Could not move the restored tree into '$dest' — it is still at '$staged'."
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return 1
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fi
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runInstallOp rm -rf "$stage"
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isSuccessful "Restored $app to $dest"
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return 0
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}
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