# AtoCore Backup and Restore Procedure

## Scope

This document defines the operational procedure for backing up and
restoring AtoCore's machine state on the Dalidou deployment. It is
the practical companion to `docs/backup-strategy.md` (which defines
the strategy) and `src/atocore/ops/backup.py` (which implements the
mechanics).

The intent is that this procedure can be followed by anyone with
SSH access to Dalidou and the AtoCore admin endpoints.

## What gets backed up

A `create_runtime_backup` snapshot contains, in order of importance:

| Artifact | Source path on Dalidou | Backup destination | Always included |
|---|---|---|---|
| SQLite database | `/srv/storage/atocore/data/db/atocore.db` | `<backup_root>/db/atocore.db` | yes |
| Project registry JSON | `/srv/storage/atocore/config/project-registry.json` | `<backup_root>/config/project-registry.json` | yes (if file exists) |
| Backup metadata | (generated) | `<backup_root>/backup-metadata.json` | yes |
| Chroma vector store | `/srv/storage/atocore/data/chroma/` | `<backup_root>/chroma/` | only when `include_chroma=true` |

The SQLite snapshot uses the online `conn.backup()` API and is safe
to take while the database is in use. The Chroma snapshot is a cold
directory copy and is **only safe when no ingestion is running**;
the API endpoint enforces this by acquiring the ingestion lock for
the duration of the copy.

What is **not** in the backup:

- Source documents under `/srv/storage/atocore/sources/vault/` and
  `/srv/storage/atocore/sources/drive/`. These are read-only
  inputs and live in the user's PKM/Drive, which is backed up
  separately by their own systems.
- Application code. The container image is the source of truth for
  code; recovery means rebuilding the image, not restoring code from
  a backup.
- Logs under `/srv/storage/atocore/logs/`.
- Embeddings cache under `/srv/storage/atocore/data/cache/`.
- Temp files under `/srv/storage/atocore/data/tmp/`.

## Backup root layout

Each backup snapshot lives in its own timestamped directory:

```
/srv/storage/atocore/backups/snapshots/
  ├── 20260407T060000Z/
  │   ├── backup-metadata.json
  │   ├── db/
  │   │   └── atocore.db
  │   ├── config/
  │   │   └── project-registry.json
  │   └── chroma/                    # only if include_chroma=true
  │       └── ...
  ├── 20260408T060000Z/
  │   └── ...
  └── ...
```

The timestamp is UTC, format `YYYYMMDDTHHMMSSZ`.

## Triggering a backup

### Option A — via the admin endpoint (preferred)

```bash
# DB + registry only (fast, safe at any time)
curl -fsS -X POST http://dalidou:8100/admin/backup \
  -H "Content-Type: application/json" \
  -d '{"include_chroma": false}'

# DB + registry + Chroma (acquires ingestion lock)
curl -fsS -X POST http://dalidou:8100/admin/backup \
  -H "Content-Type: application/json" \
  -d '{"include_chroma": true}'
```

The response is the backup metadata JSON. Save the `backup_root`
field — that's the directory the snapshot was written to.

### Option B — via the standalone script (when the API is down)

```bash
docker exec atocore python -m atocore.ops.backup
```

This runs `create_runtime_backup()` directly, without going through
the API or the ingestion lock. Use it only when the AtoCore service
itself is unhealthy and you can't hit the admin endpoint.

### Option C — manual file copy (last resort)

If both the API and the standalone script are unusable:

```bash
sudo systemctl stop atocore   # or: docker compose stop atocore
sudo cp /srv/storage/atocore/data/db/atocore.db \
        /srv/storage/atocore/backups/manual-$(date -u +%Y%m%dT%H%M%SZ).db
sudo cp /srv/storage/atocore/config/project-registry.json \
        /srv/storage/atocore/backups/manual-$(date -u +%Y%m%dT%H%M%SZ).registry.json
sudo systemctl start atocore
```

This is a cold backup and requires brief downtime.

## Listing backups

```bash
curl -fsS http://dalidou:8100/admin/backup
```

Returns the configured `backup_dir` and a list of all snapshots
under it, with their full metadata if available.

Or, on the host directly:

```bash
ls -la /srv/storage/atocore/backups/snapshots/
```

## Validating a backup

Before relying on a backup for restore, validate it:

```bash
curl -fsS http://dalidou:8100/admin/backup/20260407T060000Z/validate
```

The validator:
- confirms the snapshot directory exists
- opens the SQLite snapshot and runs `PRAGMA integrity_check`
- parses the registry JSON
- confirms the Chroma directory exists (if it was included)

A valid backup returns `"valid": true` and an empty `errors` array.
A failing validation returns `"valid": false` with one or more
specific error strings (e.g. `db_integrity_check_failed`,
`registry_invalid_json`, `chroma_snapshot_missing`).

**Validate every backup at creation time.** A backup that has never
been validated is not actually a backup — it's just a hopeful copy
of bytes.

## Restore procedure

Since 2026-04-09 the restore is implemented as a proper module
function plus CLI entry point: `restore_runtime_backup()` in
`src/atocore/ops/backup.py`, invoked as
`python -m atocore.ops.backup restore <STAMP> --confirm-service-stopped`.
It automatically takes a pre-restore safety snapshot (your rollback
anchor), handles SQLite WAL/SHM cleanly, restores the registry, and
runs `PRAGMA integrity_check` on the restored db. This replaces the
earlier manual `sudo cp` sequence.

The function refuses to run without `--confirm-service-stopped`.
This is deliberate: hot-restoring into a running service corrupts
SQLite state.

### Pre-flight (always)

1. Identify which snapshot you want to restore. List available
   snapshots and pick by timestamp:
   ```bash
   curl -fsS http://127.0.0.1:8100/admin/backup | jq '.backups[].stamp'
   ```
2. Validate it. Refuse to restore an invalid backup:
   ```bash
   STAMP=20260409T060000Z
   curl -fsS http://127.0.0.1:8100/admin/backup/$STAMP/validate | jq .
   ```
3. **Stop AtoCore.** SQLite cannot be hot-restored under a running
   process and Chroma will not pick up new files until the process
   restarts.
   ```bash
   cd /srv/storage/atocore/app/deploy/dalidou
   docker compose down
   docker compose ps   # atocore should be Exited/gone
   ```

### Run the restore

Use a one-shot container that reuses the live service's volume
mounts so every path (`db_path`, `chroma_path`, backup dir) resolves
to the same place the main service would see:

```bash
cd /srv/storage/atocore/app/deploy/dalidou
docker compose run --rm --entrypoint python atocore \
    -m atocore.ops.backup restore \
        $STAMP \
        --confirm-service-stopped
```

Output is a JSON document. The critical fields:

- `pre_restore_snapshot`: stamp of the safety snapshot of live
  state taken right before the restore. **Write this down.** If
  the restore was the wrong call, this is how you roll it back.
- `db_restored`: should be `true`
- `registry_restored`: `true` if the backup captured a registry
- `chroma_restored`: `true` if the backup captured a chroma tree
  and include_chroma resolved to true (default)
- `restored_integrity_ok`: **must be `true`** — if this is false,
  STOP and do not start the service; investigate the integrity
  error first. The restored file is still on disk but untrusted.

### Controlling the restore

The CLI supports a few flags for finer control:

- `--no-pre-snapshot` skips the pre-restore safety snapshot. Use
  this only when you know you have another rollback path.
- `--no-chroma` restores only SQLite + registry, leaving the
  current Chroma dir alone. Useful if Chroma is consistent but
  SQLite needs a rollback.
- `--chroma` forces Chroma restoration even if the metadata
  doesn't clearly indicate the snapshot has it (rare).

### Chroma restore and bind-mounted volumes

The Chroma dir on Dalidou is a bind-mounted Docker volume. The
restore cannot `rmtree` the destination (you can't unlink a mount
point — it raises `OSError [Errno 16] Device or resource busy`),
so the function clears the dir's CONTENTS and uses
`copytree(dirs_exist_ok=True)` to copy the snapshot back in. The
regression test `test_restore_chroma_does_not_unlink_destination_directory`
in `tests/test_backup.py` captures the destination inode before
and after restore and asserts it's stable — the same invariant
that protects the bind mount.

This was discovered during the first real Dalidou restore drill
on 2026-04-09. If you see a new restore failure with
`Device or resource busy`, something has regressed this fix.

### Restart AtoCore

```bash
cd /srv/storage/atocore/app/deploy/dalidou
docker compose up -d
# Wait for /health to come up
for i in 1 2 3 4 5 6 7 8 9 10; do
    curl -fsS http://127.0.0.1:8100/health \
        && break || { echo "not ready ($i/10)"; sleep 3; }
done
```

**Note on build_sha after restore:** The one-shot `docker compose run`
container does not carry the build provenance env vars that `deploy.sh`
exports at deploy time. After a restore, `/health` will report
`build_sha: "unknown"` until you re-run `deploy.sh` or manually
re-deploy. This is cosmetic — the data is correctly restored — but if
you need `build_sha` to be accurate, run a redeploy after the restore:

```bash
cd /srv/storage/atocore/app
bash deploy/dalidou/deploy.sh
```

### Post-restore verification

```bash
# 1. Service is healthy
curl -fsS http://127.0.0.1:8100/health | jq .

# 2. Stats look right
curl -fsS http://127.0.0.1:8100/stats | jq .

# 3. Project registry loads
curl -fsS http://127.0.0.1:8100/projects | jq '.projects | length'

# 4. A known-good context query returns non-empty results
curl -fsS -X POST http://127.0.0.1:8100/context/build \
  -H "Content-Type: application/json" \
  -d '{"prompt": "what is p05 about", "project": "p05-interferometer"}' | jq '.chunks_used'
```

If any of these are wrong, the restore is bad. Roll back using the
pre-restore safety snapshot whose stamp you recorded from the
restore output. The rollback is the same procedure — stop the
service and restore that stamp:

```bash
docker compose down
docker compose run --rm --entrypoint python atocore \
    -m atocore.ops.backup restore \
        $PRE_RESTORE_SNAPSHOT_STAMP \
        --confirm-service-stopped \
        --no-pre-snapshot
docker compose up -d
```

(`--no-pre-snapshot` because the rollback itself doesn't need one;
you already have the original snapshot as a fallback if everything
goes sideways.)

### Restore drill

The restore is exercised at three levels:

1. **Unit tests.** `tests/test_backup.py` has six restore tests
   (refuse-without-confirm, invalid backup, full round-trip,
   Chroma round-trip, inode-stability regression, WAL sidecar
   cleanup, skip-pre-snapshot). These run in CI on every commit.
2. **Module-level round-trip.**
   `test_restore_round_trip_reverses_post_backup_mutations` is
   the canonical drill in code form: seed baseline, snapshot,
   mutate, restore, assert mutation reversed + baseline survived
   + pre-restore snapshot captured the mutation.
3. **Live drill on Dalidou.** Periodically run the full procedure
   against the real service with a disposable drill-marker
   memory (created via `POST /memory` with `memory_type=episodic`
   and `project=drill`), following the sequence above and then
   verifying the marker is gone afterward via
   `GET /memory?project=drill`. The first such drill on
   2026-04-09 surfaced the bind-mount bug; future runs
   primarily exist to verify the fix stays fixed.

Run the live drill:

- **Before** enabling any new write-path automation (auto-capture,
  automated ingestion, reinforcement sweeps).
- **After** any change to `src/atocore/ops/backup.py` or to
  schema migrations in `src/atocore/models/database.py`.
- **After** a Dalidou OS upgrade or docker version bump.
- **At least once per quarter** as a standing operational check.
- **After any incident** that touched the storage layer.

Record each drill run (stamp, pre-restore snapshot stamp, pass/fail,
any surprises) somewhere durable — a line in the project journal
or a git commit message is enough. A drill you ran once and never
again is barely more than a drill you never ran.

## Retention policy

- **Last 7 daily backups**: kept verbatim
- **Last 4 weekly backups** (Sunday): kept verbatim
- **Last 6 monthly backups** (1st of month): kept verbatim
- **Anything older**: deleted

The retention job is **not yet implemented** and is tracked as a
follow-up. Until then, the snapshots directory grows monotonically.
A simple cron-based cleanup script is the next step:

```cron
0 4 * * * /srv/storage/atocore/scripts/cleanup-old-backups.sh
```

## Common failure modes and what to do about them

| Symptom | Likely cause | Action |
|---|---|---|
| `db_integrity_check_failed` on validation | SQLite snapshot copied while a write was in progress, or disk corruption | Take a fresh backup and validate again. If it fails twice, suspect the underlying disk. |
| `registry_invalid_json` | Registry was being edited at backup time | Take a fresh backup. The registry is small so this is cheap. |
| Restore: `restored_integrity_ok: false` | Source snapshot was itself corrupt (validation should have caught it — file a bug) or copy was interrupted mid-write | Do NOT start the service. Validate the snapshot directly with `python -m atocore.ops.backup validate <STAMP>`, try a different older snapshot, or roll back to the pre-restore safety snapshot. |
| Restore: `OSError [Errno 16] Device or resource busy` on Chroma | Old code tried to `rmtree` the Chroma mount point. Fixed on 2026-04-09 by `test_restore_chroma_does_not_unlink_destination_directory` | Ensure you're running commit 2026-04-09 or later; if you need to work around an older build, use `--no-chroma` and restore Chroma contents manually. |
| `chroma_snapshot_missing` after a restore | Snapshot was DB-only | Either rebuild via fresh ingestion or restore an older snapshot that includes Chroma. |
| Service won't start after restore | Permissions wrong on the restored files | Re-run `chown 1000:1000` (or whatever the gitea/atocore container user is) on the data dir. |
| `/stats` returns 0 documents after restore | The SQL store was restored but the source paths in `source_documents` don't match the current Dalidou paths | This means the backup came from a different deployment. Don't trust this restore — it's pulling from the wrong layout. |
| Drill marker still present after restore | Wrong stamp, service still writing during `docker compose down`, or the restore JSON didn't report `db_restored: true` | Roll back via the pre-restore safety snapshot and retry with the correct source snapshot. |

## Open follow-ups (not yet implemented)

Tracked separately in `docs/next-steps.md` — the list below is the
backup-specific subset.

1. **Retention cleanup script**: see the cron entry above. The
   snapshots directory grows monotonically until this exists.
2. **Off-Dalidou backup target**: currently snapshots live on the
   same disk as the live data. A real disaster-recovery story
   needs at least one snapshot on a different physical machine.
   The simplest first step is a periodic `rsync` to the user's
   laptop or to another server.
3. **Backup encryption**: snapshots contain raw SQLite and JSON.
   Consider age/gpg encryption if backups will be shipped off-site.
4. **Automatic post-backup validation**: today the validator must
   be invoked manually. The `create_runtime_backup` function
   should call `validate_backup` on its own output and refuse to
   declare success if validation fails.
5. **Chroma backup is currently full directory copy** every time.
   For large vector stores this gets expensive. A future
   improvement would be incremental snapshots via filesystem-level
   snapshotting (LVM, btrfs, ZFS).

**Done** (kept for historical reference):

- ~~Implement `restore_runtime_backup()` as a proper module
  function so the restore isn't a manual `sudo cp` dance~~ —
  landed 2026-04-09 in commit 3362080, followed by the
  Chroma bind-mount fix from the first real drill.

## Quickstart cheat sheet

```bash
# Daily backup (DB + registry only — fast)
curl -fsS -X POST http://127.0.0.1:8100/admin/backup \
  -H "Content-Type: application/json" -d '{}'

# Weekly backup (DB + registry + Chroma — slower, holds ingestion lock)
curl -fsS -X POST http://127.0.0.1:8100/admin/backup \
  -H "Content-Type: application/json" -d '{"include_chroma": true}'

# List backups
curl -fsS http://127.0.0.1:8100/admin/backup | jq '.backups[].stamp'

# Validate the most recent backup
LATEST=$(curl -fsS http://127.0.0.1:8100/admin/backup | jq -r '.backups[-1].stamp')
curl -fsS http://127.0.0.1:8100/admin/backup/$LATEST/validate | jq .

# Full restore (service must be stopped first)
cd /srv/storage/atocore/app/deploy/dalidou
docker compose down
docker compose run --rm --entrypoint python atocore \
    -m atocore.ops.backup restore $STAMP --confirm-service-stopped
docker compose up -d

# Live drill: exercise the full create -> mutate -> restore flow
# against the running service. The marker memory uses
# memory_type=episodic (valid types: identity, preference, project,
# episodic, knowledge, adaptation) and project=drill so it's easy
# to find via GET /memory?project=drill before and after.
#
# See the "Restore drill" section above for the full sequence.
STAMP=$(curl -fsS -X POST http://127.0.0.1:8100/admin/backup \
    -H 'Content-Type: application/json' \
    -d '{"include_chroma": true}' | jq -r '.backup_root' | awk -F/ '{print $NF}')

curl -fsS -X POST http://127.0.0.1:8100/memory \
    -H 'Content-Type: application/json' \
    -d '{"memory_type":"episodic","content":"DRILL-MARKER","project":"drill","confidence":1.0}'

cd /srv/storage/atocore/app/deploy/dalidou
docker compose down
docker compose run --rm --entrypoint python atocore \
    -m atocore.ops.backup restore $STAMP --confirm-service-stopped
docker compose up -d

# Marker should be gone:
curl -fsS 'http://127.0.0.1:8100/memory?project=drill' | jq .
```