Log new database creation, bootstrap like a transaction.

kanta/kanta.py

@@ -163,11 +163,13 @@ class Kanta(Generic[T]):
             readonly: If True, open the database read-only. No lock is acquired,
                 no background flush task is started, and transactions are
                 rejected. The file is not created if missing.
-            log: Controls migration logging. ``True`` (default) uses the
-                ``kanta.migrations`` logger. ``False`` suppresses the default
-                migration log. A :class:`~logging.Logger` instance writes
-                default migration output to that logger instead. Custom
-                ``@kanta.logmigr`` callbacks run regardless of this setting.
+            log: Controls bootstrap and migration logging. ``True`` (default)
+                uses the ``kanta.changes`` logger for bootstrap records and the
+                ``kanta.migrations`` logger for migration output. ``False``
+                suppresses the default bootstrap and migration logs. A
+                :class:`~logging.Logger` instance writes default output to that
+                logger instead. Custom ``@kanta.logmigr`` callbacks run
+                regardless of this setting.
 
         Calling ``open`` more than once on the same instance is not allowed.
 

kanta/kantaimpl.py

@@ -12,7 +12,7 @@ from typing import Any, Generic, TypeVar
 
 from kanta.callbacks import CallbackRegistry, InjectionContext
 from kanta.exceptions import DatabaseError, DataIntegrityError, ReplayError
-from kanta.logging import log_change, migration_logger
+from kanta.logging import _USER_PATH, changes_logger, log_change, migration_logger
 from kanta.migrations import MigrationResult, Migrations
 from kanta.persistence import PersistenceMixin
 from kanta.serialization import restore_data_in_place, struct_to_dict
@@ -277,13 +277,37 @@ class KantaImpl(PersistenceMixin, Generic[T]):
 
                 self.statedict = {}
                 current = struct_to_dict(self.data, serializer=self.serializer)
-                self.queue_change(
+                record = self.queue_change(
                     self.bootstrap_action,
                     current,
                     user=self.bootstrap_user,
                     mtime=self.bootstrap_mtime,
                     force=True,
                 )
+
+                if record is not None and log is not False:
+                    logger = log if isinstance(log, logging.Logger) else changes_logger
+                    logger.info("Created %s", self.filename.resolve())
+                    logfmt = self.callback_registry.build_logfmt(
+                        InjectionContext(
+                            previous_state={},
+                            current_state=current,
+                            kanta=self._kanta,
+                        )
+                    )
+                    formatted_user = self.bootstrap_user
+                    if formatted_user is not None and logfmt is not None:
+                        resolved = logfmt(formatted_user, _USER_PATH)
+                        if resolved is not None:
+                            formatted_user = resolved
+                    log_change(
+                        self.bootstrap_action,
+                        record.diff,
+                        formatted_user,
+                        previous={},
+                        logfmt=logfmt,
+                        logger=logger,
+                    )
             except Exception:
                 self.opened = False
                 self.file.close()

tests/test_callbacks.py

@@ -177,6 +177,8 @@ async def test_logfmt_class_injection(tmp_path, format_config, caplog):
     @kanta.logfmt
     class UserLogFmt(LogFmt):
         def resolve(self, value: str, path: str) -> str | None:
+            if not isinstance(value, str):
+                return None
             return self.current_state.get("users", {}).get(value, {}).get("name")
 
     await kanta.open()

tests/test_kanta_integration.py

@@ -623,6 +623,52 @@ async def test_open_log_false_suppresses_migration_log(tmp_path, format_config,
     assert not info_messages
 
 
+@pytest.mark.asyncio
+async def test_open_log_true_logs_bootstrap(tmp_path, format_config, caplog):
+    path = tmp_path / "test.db"
+    kanta = make_kanta(path, Data, format_config)
+
+    with caplog.at_level(logging.INFO, logger="kanta.changes"):
+        await kanta.open()
+        await kanta.close()
+
+    info_messages = [r.message for r in caplog.records if r.levelno == logging.INFO]
+    assert len(info_messages) >= 2
+    assert "Created" in info_messages[0]
+    assert "bootstrap" in info_messages[1]
+
+
+@pytest.mark.asyncio
+async def test_open_log_false_suppresses_bootstrap_log(tmp_path, format_config, caplog):
+    path = tmp_path / "test.db"
+    kanta = make_kanta(path, Data, format_config)
+
+    with caplog.at_level(logging.INFO, logger="kanta.changes"):
+        await kanta.open(log=False)
+        await kanta.close()
+
+    info_messages = [r for r in caplog.records if r.levelno == logging.INFO]
+    assert not info_messages
+
+
+@pytest.mark.asyncio
+async def test_open_log_custom_logger_logs_bootstrap(tmp_path, format_config, caplog):
+    path = tmp_path / "test.db"
+    kanta = make_kanta(path, Data, format_config)
+
+    custom_logger = logging.getLogger("custom.bootstrap")
+    custom_logger.setLevel(logging.INFO)
+
+    with caplog.at_level(logging.INFO, logger="custom.bootstrap"):
+        await kanta.open(log=custom_logger)
+        await kanta.close()
+
+    info_messages = [r.message for r in caplog.records if r.levelno == logging.INFO]
+    assert len(info_messages) >= 2
+    assert "Created" in info_messages[0]
+    assert "bootstrap" in info_messages[1]
+
+
 @pytest.mark.asyncio
 async def test_logmigr_callback_replaces_default_logging(
     tmp_path, format_config, caplog