"""Checking a backup: what it would restore, compared with what is in place, without restoring anything (#5823). The backup's rows come out of pg_restore as COPY text, with no database involved; the rows in place go out through COPY in the same form. They are compared table by table on their primary keys, over the columns both sides have. Nothing is written. What is compared is what a restore would replace: every table whose rows the backup carries and this Steward keeps (contents.py). Columns that are Steward's record of what it last saw (contents.ACTIVITY) and settings it writes as it runs (contents.STATE_SETTINGS) are left out of the comparison: they change by the minute and say nothing about whether the backup is good. A sealed value (crypto's ``enc:v1:`` tokens) is opened with its own side's key and compared as plaintext, so a secret sealed twice still matches. It is never shown: the report says only that it differs. A backup whose key doesn't open its own sealed values is reported, since its secrets would not come back. """ from __future__ import annotations import asyncio import hashlib import io import json import re import tempfile from dataclasses import dataclass, field from datetime import datetime, timezone from pathlib import Path from sqlalchemy import text from sqlalchemy.ext.asyncio import create_async_engine from .contents import (ACTIVITY, ACTIVITY_EVERYWHERE, AREAS, EXCLUDED, HAND_SET_ONLY, STATE_SETTINGS) from .dump import read_backup from .pgdata import async_url as _async_url from .pgdata import copy_rows, restore_script, script_tables # Names shown for a row, the first a table has; else its primary key. LABEL_COLUMNS = ("name", "username", "key", "title", "widget_key", "label", "mac") # A setting's two values are shown when they fit; longer ones are cut. SHOWN_CHARS = 120 _TOKEN = re.compile(r"enc:v1:[A-Za-z0-9_\-=]+") @dataclass class RowDiff: label: str columns: list[str] secret: bool = False backup_value: str | None = None # shown only for a setting that isn't secret here_value: str | None = None @dataclass class TableCheck: table: str same: int = 0 differ: list[RowDiff] = field(default_factory=list) only_backup: list[str] = field(default_factory=list) only_here: list[str] = field(default_factory=list) note: str = "" # a table one side lacks, columns one side lacks @property def changes(self) -> int: return len(self.differ) + len(self.only_backup) + len(self.only_here) @dataclass class AreaCheck: name: str tables: list[TableCheck] @property def same(self) -> int: return sum(t.same for t in self.tables) @property def changes(self) -> int: return sum(t.changes for t in self.tables) @dataclass class CheckReport: name: str manifest: dict schema: str # "same", "older" or "newer" backup_heads: list[str] here_heads: list[str] key_same: bool sealed: int # sealed values in the backup unopened: int # of those, how many its own key couldn't open areas: list[AreaCheck] checked_at: str = "" @property def made_at(self) -> datetime | None: try: return datetime.fromisoformat(self.manifest.get("created_at") or "") except ValueError: return None @property def rows(self) -> int: return sum(a.same + a.changes for a in self.areas) @property def changes(self) -> int: return sum(a.changes for a in self.areas) @property def ok(self) -> bool: """The backup reads back whole: its key opens its secrets. Whether it matches what is in place is `changes`; a difference isn't a fault.""" return self.unopened == 0 def summary(self) -> str: if self.unopened: return (f"The backup's key doesn't open {self.unopened} of its {self.sealed} sealed " f"value{'s' if self.sealed != 1 else ''}: those secrets wouldn't come back.") if not self.changes: tables = sum(len(a.tables) for a in self.areas) return f"Matches what is in place: {self.rows} rows across {tables} table{'s' if tables != 1 else ''}." parts = [f"{a.changes} in {a.name}" for a in self.areas if a.changes] return (f"{self.changes} difference{'s' if self.changes != 1 else ''} from what is in place: " + ", ".join(parts) + ".") def as_entry(self) -> dict: """What a backup's history row keeps of its own check.""" return {"ok": self.ok, "changes": self.changes, "rows": self.rows, "summary": self.summary()} # ── Comparing ─────────────────────────────────────────────────────────────── def _fernet(key: str): from steward.core.crypto import _make_fernet return _make_fernet(key) if key else None class _Opener: """Opens one side's sealed values, counting what it couldn't.""" def __init__(self, key: str): self.fernet = _fernet(key) self.seen = 0 self.failed = 0 def open(self, value: str) -> tuple[str, bool]: """`value` with each sealed token replaced by a digest of its plaintext (never the plaintext itself), and whether it held one.""" if "enc:v1:" not in value: return value, False def plain(m: re.Match) -> str: self.seen += 1 try: opened = self.fernet.decrypt(m.group(0)[len("enc:v1:"):].encode("ascii")) except Exception: self.failed += 1 return "\x00unopened:" + m.group(0) return "\x00sealed:" + hashlib.sha256(opened).hexdigest() return _TOKEN.sub(plain, value), True def _offset(v: str) -> str: return re.sub(r"([+-]\d\d)$", r"\1:00", v) def normalise(value: str | None, data_type: str) -> object: """A value as compared: an instant for a timestamp with zone (the two sides may print it in different zones), parsed JSON, a float.""" if value is None: return None try: if data_type == "timestamp with time zone": return datetime.fromisoformat(_offset(value)).astimezone(timezone.utc) if data_type in ("json", "jsonb"): return json.dumps(json.loads(value), sort_keys=True) if data_type in ("double precision", "real", "numeric"): return float(value) except ValueError: pass return value def _shown(value: str | None) -> str | None: if value is None: return None return value if len(value) <= SHOWN_CHARS else value[:SHOWN_CHARS - 1] + "…" @dataclass class _Side: columns: list[str] rows: list[list[str | None]] def compare_table(table: str, backup: _Side, here: _Side, *, types: dict[str, str], key: list[str], openers: tuple[_Opener, _Opener], labels: dict[str, dict[str, str]]) -> TableCheck: """One table's rows, backup against here.""" result = TableCheck(table) skip = ACTIVITY.get(table, frozenset()) | ACTIVITY_EVERYWHERE common = [c for c in backup.columns if c in here.columns and c not in skip] lacking = sorted((set(backup.columns) ^ set(here.columns)) - skip) if lacking: result.note = "Columns only one side has: " + ", ".join(lacking) + "." key = [c for c in key if c in common] or common hand_set = HAND_SET_ONLY.get(table) def index(side: _Side, opener: _Opener) -> dict[tuple, dict[str, object]]: at = {c: side.columns.index(c) for c in common} out = {} for raw in side.rows: row: dict[str, object] = {} sealed: set[str] = set() for c in common: v = raw[at[c]] if isinstance(v, str): v, was = opener.open(v) if was: sealed.add(c) row[c] = normalise(v, types.get(c, "")) if table == "app_settings" and row.get("key") in STATE_SETTINGS: continue if hand_set and not any(raw[side.columns.index(c)] for c in hand_set if c in side.columns): continue row["\x00sealed"] = sealed row["\x00raw"] = {c: raw[at[c]] for c in common} out[tuple(str(row[c]) for c in key)] = row return out theirs, ours = index(backup, openers[0]), index(here, openers[1]) def label(row: dict) -> str: raw = row["\x00raw"] if table == "host_agent_registrations" and raw.get("host_id"): return labels.get("hosts", {}).get(raw["host_id"], raw["host_id"]) if table == "ansible_target_groups": return (f"{labels.get('ansible_targets', {}).get(raw.get('target_id'), raw.get('target_id'))} in " f"{labels.get('ansible_groups', {}).get(raw.get('group_id'), raw.get('group_id'))}") for c in LABEL_COLUMNS: if raw.get(c): return str(raw[c]) return " / ".join(str(raw.get(c)) for c in key) for k in sorted(theirs.keys() | ours.keys()): b, h = theirs.get(k), ours.get(k) if h is None: result.only_backup.append(label(b)) elif b is None: result.only_here.append(label(h)) else: cols = [c for c in common if b[c] != h[c]] if not cols: result.same += 1 continue secret = bool((b["\x00sealed"] | h["\x00sealed"]) & set(cols)) diff = RowDiff(label(b), cols, secret) if table == "app_settings" and not secret: diff.backup_value = _shown(b["\x00raw"].get("value_json")) diff.here_value = _shown(h["\x00raw"].get("value_json")) result.differ.append(diff) return result def _labels(tables: dict[str, _Side]) -> dict[str, dict[str, str]]: """id → name for the tables other rows are named through.""" out: dict[str, dict[str, str]] = {} for t in ("hosts", "ansible_targets", "ansible_groups"): side = tables.get(t) if side and "id" in side.columns and "name" in side.columns: i, n = side.columns.index("id"), side.columns.index("name") out[t] = {r[i]: r[n] for r in side.rows} return out # ── Reading both sides ────────────────────────────────────────────────────── async def _backup_rows(dump: Path) -> dict[str, tuple[list[str], list[list[str | None]]]]: """Every table's rows in the dump, as pg_restore would load them.""" return script_tables(await restore_script(dump)) async def _here(database_url: str, tables: list[str]): """The rows in place for `tables`, with each column's type, each table's primary key and the migration heads.""" engine = create_async_engine(_async_url(database_url)) try: async with engine.connect() as conn: types: dict[str, dict[str, str]] = {} order: dict[str, list[str]] = {} for t, c, dt in (await conn.execute(text( "SELECT table_name, column_name, data_type FROM information_schema.columns " "WHERE table_schema = 'public' AND table_name = ANY(:t) " "ORDER BY table_name, ordinal_position"), {"t": tables})).all(): types.setdefault(t, {})[c] = dt order.setdefault(t, []).append(c) keys: dict[str, list[str]] = {} for t, c in (await conn.execute(text( "SELECT cl.relname, a.attname FROM pg_index i " "JOIN pg_class cl ON cl.oid = i.indrelid " "JOIN pg_namespace ns ON ns.oid = cl.relnamespace " "JOIN pg_attribute a ON a.attrelid = cl.oid AND a.attnum = ANY(i.indkey) " "WHERE i.indisprimary AND ns.nspname = 'public' AND cl.relname = ANY(:t) " "ORDER BY cl.relname, a.attnum"), {"t": tables})).all(): keys.setdefault(t, []).append(c) heads = sorted((await conn.execute(text("SELECT version_num FROM alembic_version"))).scalars()) raw = (await conn.get_raw_connection()).driver_connection rows: dict[str, _Side] = {} for t in tables: if t not in order: continue buf = io.BytesIO() await raw.copy_from_table(t, columns=order[t], output=buf, format="text") rows[t] = _Side(order[t], copy_rows(buf.getvalue())) return rows, types, keys, heads finally: await engine.dispose() def known_revisions(plugin_dirs: list[Path] | None = None) -> set[str]: """Every migration revision this Steward has, core and plugins: a backup head not among them was made by a newer Steward.""" import steward roots = [Path(steward.__file__).parent / "migrations" / "versions"] for d in plugin_dirs or [Path(steward.__file__).parent.parent / "plugins"]: if Path(d).is_dir(): roots += [p / "migrations" / "versions" for p in Path(d).iterdir()] found = set() for root in roots: if root.is_dir(): for f in root.glob("*.py"): m = re.search(r'^revision\s*(?::\s*str\s*)?=\s*["\']([^"\']+)["\']', f.read_text(errors="replace"), re.M) if m: found.add(m.group(1)) return found def schema_of(backup_heads: list[str], here_heads: list[str], known: set[str]) -> str: if sorted(backup_heads) == sorted(here_heads): return "same" return "newer" if any(h not in known for h in backup_heads) else "older" async def check_backup(path: Path, database_url: str, here_key: str, *, plugin_dirs: list[Path] | None = None, name: str = "") -> CheckReport: """Compare the backup at `path` with the database at `database_url`. Raises BackupError when the file isn't a backup or can't be read.""" with tempfile.TemporaryDirectory(prefix="steward-check-") as tmp: info, dump, backup_key = await asyncio.to_thread(read_backup, path, Path(tmp)) theirs = await _backup_rows(dump) tables = sorted(t for t in theirs if t not in EXCLUDED) here, types, keys, heads = await _here(database_url, tables) openers = (_Opener(backup_key), _Opener(here_key)) backup_sides = {t: _Side(*theirs[t]) for t in tables} labels = _labels(backup_sides) for t, names in _labels(here).items(): # a name in place wins labels[t] = {**labels.get(t, {}), **names} checks: dict[str, TableCheck] = {} for t in tables: if t not in here: checks[t] = TableCheck(t, only_backup=[f"{len(theirs[t][1])} rows"], note="This Steward has no such table.") continue checks[t] = compare_table(t, backup_sides[t], here[t], types=types.get(t, {}), key=keys.get(t, []), openers=openers, labels=labels) areas = [] placed: set[str] = set() for area, members in AREAS: found = [checks[t] for t in members if t in checks] placed |= set(members) if found: areas.append(AreaCheck(area, found)) rest = [checks[t] for t in tables if t not in placed] if rest: areas.append(AreaCheck("Other", rest)) backup_heads = sorted(info.get("migration_heads") or []) return CheckReport( name=name or path.name, manifest=info, schema=schema_of(backup_heads, heads, known_revisions(plugin_dirs)), backup_heads=backup_heads, here_heads=heads, key_same=backup_key == here_key, sealed=openers[0].seen, unopened=openers[0].failed, areas=areas, checked_at=datetime.now(timezone.utc).isoformat())