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/**
* backups/restore-script.ts — pure builders for the restore helper-container
* commands. Two shapes, matching the two restore modes:
*
* new-location: restic restores the requested volumes into a fresh target
* directory. Non-destructive — nothing live is touched.
*
* in-place: restic restores each volume into a staging dir on the live
* volume's own filesystem, then the phase-marked swap commits it
* (see ./swap). The one destructive mode, made safe by staging.
*
* The restic restore for in-place must land each `/volumes/<name>` include under
* `<live>/.dockhand-restore-new`, which happens by pointing `--target` at the
* live volume root and letting restic recreate the `/volumes/<name>` path there.
*/
import { shellQuote } from './restic-script';
import { buildInPlaceRestoreScript, SWAP_NEW } from './swap';
/**
* Build the in-place restore script. For each live volume root, restic restores
* that include into `<live>/.dockhand-restore-new` (staging), then the swap
* commits. `liveRoots` are the `/volumes/<name>` bind destinations being
* restored, already validated as safe paths.
*
* We run one restic per volume so each lands in its own staging dir. restic's
* `--target <live>` plus `--include /volumes/<name>` writes to
* `<live>/volumes/<name>`, so we first restore to a scratch target then move the
* restored subtree into `.dockhand-restore-new` — but simpler and equivalent:
* restore with `--target <live>/.dockhand-restore-new` and strip the leading
* `/volumes/<name>` via restic's path handling. To keep the shell simple and
* robust we restore into the staging dir and let the swap move top-level entries.
*/
export function buildInPlaceRestore(
snapshotId: string,
liveRoots: string[],
flags: string[],
): string {
// One restic restore per volume, each into that volume's staging dir. Using a
// subshell per restore so a non-zero restic aborts the whole script (set -e in
// buildInPlaceRestoreScript) before any swap runs.
const restores = liveRoots.map((live) => {
const staging = `${live}/${SWAP_NEW}`;
const include = live; // e.g. /volumes/data
const args = [
'restore', '--json', snapshotId,
'--target', staging,
'--include', include,
...flags,
];
// restic writes <staging><include> (it recreates the include's full path
// under the target). Flatten so the swap sees the volume contents directly
// at the staging root: move <staging><include>/* up to <staging>/, then
// remove the recreated scaffold (the first path component under staging).
const restic = `restic ${args.map(shellQuote).join(' ')}`;
const nested = shellQuote(`${staging}${include}`);
const stagingQ = shellQuote(staging);
// include is always `/volumes/<name>`, so the scaffold under staging is its
// first path component, e.g. `volumes`.
const firstComponent = include.replace(/^\/+/, '').split('/')[0];
const scaffold = shellQuote(`${staging}/${firstComponent}`);
const flatten =
`( if [ -d ${nested} ]; then cd ${nested}; ` +
`for e in * .[!.]* ..?*; do [ -e "$e" ] || [ -L "$e" ] || continue; mv -- "$e" ${stagingQ}/; done; ` +
`fi )`;
// Narrate FS operations to stderr (streamed live to the restore log).
const say = (m: string) => `echo ${shellQuote(`[dockhand] ${m}`)} >&2`;
// SAFE: `scaffold` = <live>/.dockhand-restore-new/volumes — the `volumes`
// rung INSIDE our own staging dir, NEVER <live>/volumes. So this rm can't
// touch a user's own `volumes/` directory at the live root (that's the bug
// the CLONE path had before it moved to a staging dir — see buildCloneRestore).
return [
`${say(`Restoring ${include} into staging dir ${SWAP_NEW}`)}`,
restic,
flatten,
`rm -rf ${scaffold}`,
].join('; ');
}).join('; ');
return buildInPlaceRestoreScript(liveRoots, restores);
}
/**
* Build the CLONE restore script: restic restores each volume's `/volumes/<name>`
* include DIRECTLY into that volume's mount root (a fresh named volume or host
* path on the target env, bound `:rw` into the helper). Unlike in-place there is
* NO staging dir and NO swap — the destination is fresh, so we write straight
* into it. Unlike new-location (`--target <path>` loose files) the data lands at
* the mount root so a container mounting that volume sees it as its own contents.
*
* `mountRoots` are the `/volumes/<name>` bind destinations inside the helper,
* already validated as safe. restic's `--target <root>` + `--include <root>`
* writes `<root>/volumes/<name>`, so we flatten that subtree up to `<root>/` and
* remove the recreated scaffold — same mechanic as in-place's flatten, minus the
* swap wrapper. Runs under `set -e` so any restic/flatten failure aborts.
*/
export function buildCloneRestore(
snapshotId: string,
mountRoots: string[],
flags: string[],
): string {
// Per-restore staging name: two clones that happen to target the SAME host path
// (e.g. two different snapshots restored into /srv/shared, from different repos so
// the per-repo serializer doesn't order them) must NOT share one staging dir, or
// one's `rm -rf` would wipe the other's in-flight files. Keying the staging dir on
// the snapshot id makes each restore's staging unique; two clones of the SAME
// snapshot are already serialized per-repo, so they never overlap.
const staging_name = cloneStagingName(snapshotId);
const restores = mountRoots.map((root) => {
const include = root; // e.g. /volumes/data — mounted at the helper root
// DATA SAFETY: restic recreates the include path under `--target`, so we must
// flatten `.../volumes/<name>/*` up to the mount root. We do that via an
// ISOLATED staging dir INSIDE the mount (mirroring the in-place path), NOT by
// writing straight into the mount and `rm -rf`-ing a `volumes` scaffold there.
// The old approach did `rm -rf <mount>/volumes`, which would delete a user's
// OWN `volumes/` sub-directory if the bind destination happened to contain one.
// Restic runs WITHOUT --delete, so files already at the mount are preserved;
// the restored files are moved in ON TOP (overwriting only name collisions),
// then the staging dir — created by us, never the user — is removed.
const staging = `${root}/${staging_name}`;
const args = [
'restore', '--json', snapshotId,
'--target', staging,
'--include', include,
...flags,
];
const restic = `restic ${args.map(shellQuote).join(' ')}`;
const nested = shellQuote(`${staging}${include}`); // <staging>/volumes/<name>
const nestedDot = shellQuote(`${staging}${include}/.`);
const rootQ = shellQuote(root);
const stagingQ = shellQuote(staging);
// MERGE the restored tree onto the mount root: `cp -a <staging>/./.` copies
// every entry (incl. dotfiles) into the destination, RECURSIVELY MERGING into
// existing directories. Plain `mv` can't do this — it refuses ("Directory not
// empty") when a restored dir (e.g. `blueprints`) already exists at the mount,
// which is exactly the cross-env restore case where data is already present.
// cp overwrites file collisions and keeps the user's other files intact.
const move =
`( if [ -d ${nested} ]; then cp -a ${nestedDot} ${rootQ}/; fi )`;
// Narrate each FS operation to stderr (streamed live to the restore log with a
// [dockhand] pill) so the user sees exactly what happens to their files.
const say = (m: string) => `echo ${shellQuote(`[dockhand] ${m}`)} >&2`;
// Remove ONLY our staging dir (recursive is safe — it's ours, and the payload
// was copied out). Never touches any user directory at the mount.
return [
`${say(`Cloning into ${root} (staging dir ${staging_name})`)}`,
`rm -rf ${stagingQ}`,
restic,
`${say(`Moving restored files into ${root}`)}`,
move,
`${say(`Cleaning up staging dir at ${root}`)}`,
`rm -rf ${stagingQ}`,
].join('; ');
}).join('; ');
return `set -e; ${restores}`;
}
/** The isolated staging sub-directory a clone restore extracts into before moving
* files up to the mount root. Named/owned by Dockhand (so its cleanup can never
* touch the user's own files at the destination) and keyed on the snapshot id (so
* two concurrent clones into the same host path don't share — and wipe — one dir). */
export function cloneStagingName(snapshotId: string): string {
const safe = snapshotId.replace(/[^a-zA-Z0-9]/g, '').slice(0, 16) || 'x';
return `.dockhand-clone-${safe}`;
}
/**
* Build the new-location restore command: restic restores the requested volumes
* (or the whole snapshot) into a fresh target directory. Non-destructive.
*/
export function buildNewLocationRestore(
snapshotId: string,
targetPath: string,
includes: string[],
flags: string[],
): string[] {
const args = ['restore', '--json', snapshotId, '--target', targetPath];
for (const inc of includes) args.push('--include', inc);
args.push(...flags);
return args;
}