feat: add StoreManager singleton for centralized store migration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile.sidecars

@@ -70,6 +70,7 @@ COPY bot_bottle/migrations.py        /app/migrations.py
 COPY bot_bottle/db_store.py          /app/db_store.py
 COPY bot_bottle/queue_store.py       /app/queue_store.py
 COPY bot_bottle/audit_store.py       /app/audit_store.py
+COPY bot_bottle/store_manager.py     /app/store_manager.py
 COPY bot_bottle/supervise.py         /app/supervise.py
 COPY bot_bottle/supervise_server.py  /app/supervise_server.py
 COPY bot_bottle/sidecar_init.py      /app/sidecar_init.py

bot_bottle/cli/__init__.py

@@ -7,11 +7,9 @@ from __future__ import annotations
 
 import sys
 
-from ..audit_store import AuditStore
-from ..db_store import DbVersionError
 from ..log import Die, die, error
 from ..manifest import ManifestError
-from ..queue_store import QueueStore
+from ..store_manager import StoreManager
 from ._common import PROG
 from . import list as _list_mod
 from .cleanup import cmd_cleanup
@@ -77,9 +75,8 @@ def main(argv: list[str] | None = None) -> int:
     if handler is None:
         usage()
         die(f"unknown command: {command}")
-    queue_store = QueueStore("")
+    mgr = StoreManager.instance()
-    audit_store = AuditStore()
+    if not mgr.check_migrations():
-    if not queue_store.check_migrations() or not audit_store.check_migrations():
         sys.stderr.write("bot-bottle: database schema is out of date\n")
         sys.stderr.write("Migrate now? [y/N] ")
         sys.stderr.flush()
@@ -90,8 +87,7 @@ def main(argv: list[str] | None = None) -> int:
         if answer != "y":
             error("migration required — re-run and confirm to migrate")
             return 1
-        queue_store.migrate()
+        mgr.migrate()
-        audit_store.migrate()
     try:
         return handler(rest) or 0
     except ManifestError as e:

bot_bottle/store_manager.py

@@ -0,0 +1,60 @@
+"""Singleton manager for all bot-bottle SQLite stores (PRD 0013)."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+try:
+    from .audit_store import AuditStore
+    from .queue_store import QueueStore
+except ImportError:
+    from audit_store import AuditStore  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+    from queue_store import QueueStore  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+
+_instance: StoreManager | None = None
+
+
+class StoreManager:
+    """Owns db_path and delegates migrate/check_migrations across all stores.
+
+    Use instance() for normal access. Call reset(db_path) in tests to swap
+    the singleton to a temp path, then reset() with no args to restore the
+    default."""
+
+    def __init__(self, db_path: Path | None = None) -> None:
+        if db_path is None:
+            # Lazy import to avoid a circular dependency: supervise imports
+            # StoreManager at module level; StoreManager must not import
+            # supervise at module level in return.
+            try:
+                from .supervise import host_db_path
+            except ImportError:
+                from supervise import host_db_path  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+            db_path = host_db_path()
+        self.db_path = db_path
+
+    @classmethod
+    def instance(cls) -> StoreManager:
+        global _instance
+        if _instance is None:
+            _instance = cls()
+        return _instance
+
+    @classmethod
+    def reset(cls, db_path: Path | None = None) -> None:
+        """Replace the singleton. Pass db_path for test isolation; omit to restore default."""
+        global _instance
+        _instance = cls(db_path)
+
+    def check_migrations(self) -> bool:
+        return (
+            QueueStore("", self.db_path).check_migrations()
+            and AuditStore(self.db_path).check_migrations()
+        )
+
+    def migrate(self) -> None:
+        QueueStore("", self.db_path).migrate()
+        AuditStore(self.db_path).migrate()
+
+
+__all__ = ["StoreManager"]

bot_bottle/supervise.py

@@ -222,10 +222,12 @@ class AuditEntry:
 try:
     from .queue_store import QueueStore
     from .audit_store import AuditStore
+    from .store_manager import StoreManager
 except ImportError:
     # Sidecar bundle: files are flat-copied under /app, not a package.
     from queue_store import QueueStore  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
     from audit_store import AuditStore  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
+    from store_manager import StoreManager  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
 
 
 # --- Queue I/O -------------------------------------------------------------
@@ -356,12 +358,11 @@ class Supervise(ABC):
         """Stage the host database. Returns the plan; `internal_network`
         must be set by the launch step before .start runs."""
         del stage_dir
-        db_path = host_db_path()
+        mgr = StoreManager.instance()
-        QueueStore(slug).migrate()
+        mgr.migrate()
-        AuditStore(db_path).migrate()
         return SupervisePlan(
             slug=slug,
-            db_path=db_path,
+            db_path=mgr.db_path,
         )
 
 # --- Helpers ---------------------------------------------------------------
@@ -384,6 +385,7 @@ __all__ = [
     "Proposal",
     "QueueStore",
     "Response",
+    "StoreManager",
     "STATUSES",
     "STATUS_APPROVED",
     "STATUS_MODIFIED",

tests/unit/test_cli_dispatch.py

@@ -15,6 +15,7 @@ from bot_bottle.cli import main
 from bot_bottle.db_store import DbStore
 from bot_bottle.log import Die
 from bot_bottle.manifest import ManifestError
+from bot_bottle.store_manager import StoreManager
 
 
 class TestMainDispatch(unittest.TestCase):
@@ -22,6 +23,7 @@ class TestMainDispatch(unittest.TestCase):
         patcher = patch.object(DbStore, "check_migrations", return_value=True)
         self._mock_check = patcher.start()
         self.addCleanup(patcher.stop)
+        self.addCleanup(StoreManager.reset)
 
     def test_no_args_prints_usage_returns_2(self) -> None:
         with patch("sys.stderr", io.StringIO()):