Rewrite durable task lifecycle, gallery indexing and subscription publication

scripts/migrate_user_links.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Add stable user identity to subscription bindings and access records.
+
+The default invocation only reports schema changes. --apply creates a consistent
+SQLite backup before the transaction. Run against an isolated database first.
+"""
+import argparse
+import datetime
+import json
+from pathlib import Path
+import sqlite3
+
+
+def migrate(db_path: Path, apply: bool = False) -> dict:
+    if not db_path.is_file():
+        raise ValueError("database must already exist")
+    uri = db_path.resolve().as_uri() + ("?mode=rw" if apply else "?mode=ro")
+    with sqlite3.connect(uri, uri=True) as db:
+        changes = []
+        for table in ("sub_bind", "sub_update_record"):
+            columns = {row[1] for row in db.execute(f'PRAGMA table_info("{table}")')}
+            if not columns:
+                raise ValueError(f"required table missing: {table}")
+            if "user_id" not in columns:
+                changes.append(f"add {table}.user_id")
+        duplicates = db.execute(
+            "select count(*) from (select username from User group by username having count(*) > 1)"
+        ).fetchone()[0]
+        if duplicates:
+            raise ValueError("ambiguous duplicate usernames; resolve identities before migration")
+        result = {"apply": apply, "schema_changes": changes}
+        if not apply:
+            return result
+        stamp = datetime.datetime.now(datetime.timezone.utc).strftime("%Y%m%dT%H%M%S%fZ")
+        backup = db_path.with_name(db_path.name + ".before-user-links." + stamp)
+        with sqlite3.connect(backup) as snapshot:
+            db.backup(snapshot)
+        backup.chmod(0o600)
+        db.execute("BEGIN IMMEDIATE")
+        try:
+            for change in changes:
+                table = change.split()[1].split(".")[0]
+                db.execute(f'ALTER TABLE "{table}" ADD COLUMN user_id INTEGER REFERENCES User(id)')
+            for table in ("sub_bind", "sub_update_record"):
+                db.execute(f'UPDATE "{table}" SET user_id=(SELECT id FROM User WHERE username="{table}".user) WHERE user_id IS NULL')
+            db.execute("CREATE UNIQUE INDEX IF NOT EXISTS User_username_uindex ON User(username)")
+            db.execute("CREATE UNIQUE INDEX IF NOT EXISTS idx_sub_bind_user_id ON sub_bind(user_id) WHERE user_id IS NOT NULL")
+            db.execute("CREATE INDEX IF NOT EXISTS idx_sub_record_user_id ON sub_update_record(user_id, id)")
+            db.commit()
+        except BaseException:
+            db.rollback()
+            raise
+        result["backup"] = str(backup)
+        result["unresolved_bindings"] = db.execute("select count(*) from sub_bind where user_id is null").fetchone()[0]
+        result["unresolved_records"] = db.execute("select count(*) from sub_update_record where user_id is null").fetchone()[0]
+        return result
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("database", type=Path)
+    parser.add_argument("--apply", action="store_true")
+    args = parser.parse_args()
+    print(json.dumps(migrate(args.database, args.apply), ensure_ascii=False))