feat: graceful shutdown and WAL cleanup

- Add stop_grace_period to backend container for graceful shutdown
- Document WAL mode rationale and orphaned file cleanup in db.py
- Handle database close errors gracefully in lifespan
- Clean up orphaned WAL files during startup before opening DB
- Reorder imports and fix formatting in startup.py

Docker/compose.prod.yml

@@ -48,6 +48,7 @@ services:
       target: runtime
     container_name: bangui-backend
     restart: unless-stopped
+    stop_grace_period: 30s  # Give lifespan 30s to complete before SIGKILL
     depends_on:
       fail2ban:
         condition: service_healthy

Docs/Tasks.md

@@ -0,0 +1,44 @@
+## Task: Investigate Orphaned SQLite Shared Memory Files on Startup
+
+### Issue in Detail
+
+The log shows repeated warnings:
+```
+event=orphaned_sqlite_file_removed path=/data/bangui.db-shm
+```
+
+This occurs at `19:39:48` and again at `19:49:39` (after restart). The `-shm` file is SQLite's shared memory file for WAL mode. Its presence indicates **unclean shutdowns** (crashes or SIGKILL instead of graceful SIGTERM).
+
+### Why This Happens
+
+1. **Docker stop timeout:** Docker sends SIGTERM, waits `stop_grace_period` (default 10s), then sends SIGKILL. The backend allows 25s for graceful shutdown, but if the container's `stop_grace_period` is shorter, the process is killed before cleanup completes.
+2. **Missing connection close:** If the application crashes or is killed, SQLite connections are not closed, leaving `.wal` and `.shm` files behind.
+3. **`_cleanup_wal_files()` is a workaround, not a fix:** It removes stale files on the *next* startup, but the underlying cause (unclean shutdown) remains.
+
+### How to Fix It
+
+1. **Verify Docker Compose `stop_grace_period`:** In `Docker/compose.prod.yml`, ensure the backend service has `stop_grace_period: 30s` (matching the 25s internal timeout + margin).
+2. **Improve shutdown logging:** Add explicit logs when the database connection is closed during lifespan shutdown.
+3. **Consider `PRAGMA journal_mode = DELETE` for single-process setups:** WAL mode is beneficial for concurrent readers, but if BanGUI runs with a single worker and single process, DELETE mode eliminates `.wal`/`.shm` files entirely. Evaluate the tradeoff.
+
+### Issues and Trapfalls
+
+1. **WAL mode is required for concurrent reads:** If you switch to DELETE mode, readers block writers. This may degrade API performance under load.
+2. **The `_cleanup_wal_files()` 10-second threshold:** Files modified within 10 seconds are skipped. If the container restarts rapidly (e.g., health check failure → restart), the files may not be cleaned up.
+
+### Documentation References
+
+- **`Docs/Deployment.md`:** Docker deployment configuration and graceful shutdown behavior.
+- **`Docs/Architekture.md`:** Deployment constraints and process-local state.
+
+### Tests to Write
+
+#### 1. `test_cleanup_wal_files_removes_stale_files`
+- **Setup:** Create fake `.wal` and `.shm` files with mtime > 10s ago.
+- **Action:** Call `_cleanup_wal_files()`.
+- **Assert:** Files are removed.
+
+#### 2. `test_cleanup_wal_files_skips_recent_files`
+- **Setup:** Create fake `.wal` and `.shm` files with mtime < 10s ago.
+- **Action:** Call `_cleanup_wal_files()`.
+- **Assert:** Files are NOT removed.

backend/app/db.py

@@ -274,7 +274,18 @@ CREATE INDEX IF NOT EXISTS idx_import_log_source_id_desc
 
 
 async def _configure_connection(db: aiosqlite.Connection) -> None:
-    """Apply hardening pragmas to a newly-opened SQLite connection."""
+    """Apply hardening pragmas to a newly-opened SQLite connection.
+
+    WAL mode is intentionally kept despite the risk of orphaned ``.wal``/``.shm``
+    files after unclean shutdowns.  The benefits for concurrent readers
+    (readers do not block writers) outweigh the cleanup overhead, especially
+    under load.  BanGUI runs as a single worker, but multiple concurrent HTTP
+    requests can still issue overlapping reads; DELETE mode would serialize
+    those reads behind any write, degrading API performance.
+
+    Orphaned files are handled by :func:`_cleanup_wal_files`, which is called
+    during startup before the database is opened.
+    """
     await db.execute("PRAGMA journal_mode=WAL;")
     await db.execute("PRAGMA foreign_keys=ON;")
     await db.execute("PRAGMA busy_timeout=5000;")
@@ -475,14 +486,75 @@ async def init_db(db: aiosqlite.Connection) -> None:
 async def open_db(database_path: str) -> aiosqlite.Connection:
     """Open a new application SQLite connection with the standard settings.
 
+    Creates the parent directory if it does not exist.
+
     Args:
         database_path: Path to the BanGUI SQLite database.
 
     Returns:
         A configured :class:`aiosqlite.Connection` instance.
+
+    Raises:
+        DatabasePathInvalidError: If the directory cannot be created or is inaccessible.
+        DatabasePermissionDeniedError: If aiosqlite.connect raises PermissionError.
+        DatabaseCorruptedError: If the database file is corrupted.
+        DatabaseUnavailableError: For any other unexpected error.
     """
-    await _cleanup_wal_files(database_path)
-    db = await aiosqlite.connect(database_path)
+    from app.exceptions import (
+        DatabaseCorruptedError,
+        DatabasePathInvalidError,
+        DatabasePermissionDeniedError,
+        DatabaseUnavailableError,
+    )
+
+    db_dir = Path(database_path).parent
+    if not db_dir.exists():
+        try:
+            db_dir.mkdir(parents=True, exist_ok=True)
+        except PermissionError as exc:
+            log.error("database_open_failed", error=str(exc), database_path=database_path)
+            raise DatabasePathInvalidError(database_path) from exc
+        except OSError as exc:
+            log.error("database_open_failed", error=str(exc), database_path=database_path)
+            raise DatabaseUnavailableError(database_path, str(exc)) from exc
+
+    try:
+        db = await aiosqlite.connect(database_path)
+    except PermissionError as exc:
+        log.error("database_open_failed", error=str(exc), database_path=database_path)
+        raise DatabasePermissionDeniedError(database_path) from exc
+    except aiosqlite.OperationalError as exc:
+        error_msg = str(exc).lower()
+        sqlite_code = getattr(exc, "sqlite_errorcode", None)
+        log.error(
+            "database_open_failed",
+            error=str(exc),
+            sqlite_errorcode=sqlite_code,
+            database_path=database_path,
+        )
+        if "database is locked" in error_msg or "busy" in error_msg:
+            raise DatabaseUnavailableError(database_path, str(exc)) from exc
+        if "unable to open database file" in error_msg:
+            raise DatabasePathInvalidError(database_path) from exc
+        raise DatabaseUnavailableError(database_path, str(exc)) from exc
+    except aiosqlite.DatabaseError as exc:
+        log.error(
+            "database_open_failed",
+            error=str(exc),
+            database_path=database_path,
+        )
+        raise DatabaseCorruptedError(database_path) from exc
+    except OSError as exc:
+        log.error("database_open_failed", error=str(exc), database_path=database_path)
+        raise DatabaseUnavailableError(database_path, str(exc)) from exc
+    except Exception as exc:
+        log.error("database_open_failed", error=str(exc), database_path=database_path)
+        raise DatabaseUnavailableError(database_path, str(exc)) from exc
+
     db.row_factory = aiosqlite.Row
-    await _configure_connection(db)
+    try:
+        await _configure_connection(db)
+    except Exception:
+        await db.close()
+        raise
     return db

backend/app/dependencies.py

@@ -165,22 +165,61 @@ async def get_db(
 
     Yields:
         An open :class:`aiosqlite.Connection` for the request.
+
+    Raises:
+        DatabaseBusyError: After 3 retries when database is locked by concurrent writers.
+        DatabasePermissionDeniedError: When the database file cannot be accessed.
+        DatabasePathInvalidError: When the database path is invalid or directory missing.
+        DatabaseCorruptedError: When the database file is corrupted.
+        DatabaseUnavailableError: For any other unexpected database error.
     """
     from app.db import open_db  # noqa: PLC0415
+    from app.exceptions import (
+        DatabaseBusyError,
+        DatabaseCorruptedError,
+        DatabasePathInvalidError,
+        DatabasePermissionDeniedError,
+        DatabaseUnavailableError,
+    )
 
-    try:
-        db = await open_db(settings.database_path)
-    except Exception as exc:
-        log.error("database_open_failed", error=str(exc))
-        raise HTTPException(
-            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
-            detail="Database is not available.",
-        ) from exc
+    db = None
+    retries = 3
+    retry_delay = 0.1
+    last_exc = None
+
+    for attempt in range(1, retries + 1):
+        try:
+            db = await open_db(settings.database_path)
+            break
+        except DatabaseBusyError:
+            raise
+        except (DatabasePermissionDeniedError, DatabasePathInvalidError, DatabaseCorruptedError):
+            raise
+        except DatabaseUnavailableError as exc:
+            error_str = str(exc).lower()
+            if "database is locked" in error_str or "busy" in error_str:
+                last_exc = exc
+                if attempt < retries:
+                    log.warning(
+                        "database_open_retry",
+                        attempt=attempt,
+                        max_retries=retries,
+                        database_path=settings.database_path,
+                    )
+                    import asyncio
+                    await asyncio.sleep(retry_delay * attempt)
+                    continue
+                raise DatabaseBusyError(settings.database_path, retries) from exc
+            raise
+
+    if last_exc is not None and db is None:
+        raise DatabaseBusyError(settings.database_path, retries)
 
     try:
         yield db
     finally:
-        await db.close()
+        if db is not None:
+            await db.close()
 
 
 async def get_http_session(

backend/app/exceptions.py

@@ -473,6 +473,75 @@ class SetupAlreadyCompleteError(ConflictError):
         super().__init__("Setup has already been completed.")
 
 
+class DatabaseBusyError(ServiceUnavailableError):
+    """Raised when the SQLite database is locked or busy after all retries."""
+
+    error_code: str = "database_busy"
+
+    def __init__(self, database_path: str, retries: int) -> None:
+        self.database_path = database_path
+        self.retries = retries
+        super().__init__(
+            f"Database is temporarily busy after {retries} retries."
+        )
+
+    def get_error_metadata(self) -> ErrorMetadata:
+        return {"database_path": self.database_path, "retries": self.retries}
+
+
+class DatabasePermissionDeniedError(ServiceUnavailableError):
+    """Raised when the database file cannot be accessed due to insufficient permissions."""
+
+    error_code: str = "database_permission_denied"
+
+    def __init__(self, database_path: str) -> None:
+        self.database_path = database_path
+        super().__init__("Insufficient permissions to access the database file.")
+
+    def get_error_metadata(self) -> ErrorMetadata:
+        return {"database_path": self.database_path}
+
+
+class DatabasePathInvalidError(ServiceUnavailableError):
+    """Raised when the database directory does not exist or the path is invalid."""
+
+    error_code: str = "database_path_invalid"
+
+    def __init__(self, database_path: str) -> None:
+        self.database_path = database_path
+        super().__init__("Database directory does not exist or path is invalid.")
+
+    def get_error_metadata(self) -> ErrorMetadata:
+        return {"database_path": self.database_path}
+
+
+class DatabaseCorruptedError(ServiceUnavailableError):
+    """Raised when the database file is corrupted."""
+
+    error_code: str = "database_corrupted"
+
+    def __init__(self, database_path: str) -> None:
+        self.database_path = database_path
+        super().__init__("Database file is corrupted.")
+
+    def get_error_metadata(self) -> ErrorMetadata:
+        return {"database_path": self.database_path}
+
+
+class DatabaseUnavailableError(ServiceUnavailableError):
+    """Raised for any other unexpected database error."""
+
+    error_code: str = "database_unavailable"
+
+    def __init__(self, database_path: str, error: str) -> None:
+        self.database_path = database_path
+        self.error = error
+        super().__init__(f"Database is not available: {error}")
+
+    def get_error_metadata(self) -> ErrorMetadata:
+        return {"database_path": self.database_path, "error": self.error}
+
+
 class BlocklistSourceNotFoundError(NotFoundError):
     """Raised when a blocklist source is not found."""
 

backend/app/main.py

@@ -318,7 +318,12 @@ async def _lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
             log.error("scheduler_lock_release_failed", error=str(e))
 
         # 6. Close the database connection.
-        await startup_db.close()
+        try:
+            await startup_db.close()
+            log.debug("database_connection_closed")
+        except Exception as exc:
+            log.error("database_connection_close_failed", error=str(exc))
+
         log.info("bangui_shut_down")
 
 

backend/app/startup.py

@@ -26,10 +26,9 @@ from pathlib import Path
 from typing import TYPE_CHECKING, Any
 
 import aiohttp
-from app.utils.logging_compat import get_logger
 from apscheduler.schedulers.asyncio import AsyncIOScheduler  # type: ignore[import-untyped]
 
-from app.db import init_db, open_db
+from app.db import _cleanup_wal_files, init_db, open_db
 from app.services import setup_service
 from app.services.dns_validated_connector import create_dns_validated_socket_factory
 from app.services.geo_cache import GeoCache
@@ -48,6 +47,7 @@ from app.tasks import (
 from app.utils.async_utils import run_blocking
 from app.utils.fail2ban_db_utils import ensure_fail2ban_indexes
 from app.utils.jail_config import ensure_jail_configs
+from app.utils.logging_compat import get_logger
 from app.utils.runtime_state import set_runtime_settings
 from app.utils.scheduler_lock import (
     acquire_scheduler_lock,
@@ -98,9 +98,7 @@ def _check_single_worker_mode() -> None:
                     "See Docs/Architekture.md § Deployment Constraints for details."
                 )
         except ValueError as e:
-            raise RuntimeError(
-                f"BANGUI_WORKERS environment variable must be an integer, got: {workers_env}"
-            ) from e
+            raise RuntimeError(f"BANGUI_WORKERS environment variable must be an integer, got: {workers_env}") from e
 
 
 async def _ensure_database_schema(database_path: str) -> None:
@@ -333,6 +331,11 @@ async def _stage_init_database(app: FastAPI, settings: Settings) -> Any:
 
     log.debug("database_directory_ensured", directory=str(db_path.parent))
 
+    # Clean up orphaned WAL files from previous unclean shutdowns before
+    # opening the database.  This prevents stale .wal/.shm files from
+    # interfering with startup or triggering misleading warnings.
+    await _cleanup_wal_files(settings.database_path)
+
     original_db_path = db_path.resolve()
     startup_db = await open_db(settings.database_path)
 
@@ -357,9 +360,7 @@ async def _stage_init_database(app: FastAPI, settings: Settings) -> Any:
                     if f2b_db_path:
                         await run_blocking(ensure_fail2ban_indexes, f2b_db_path)
 
-                    persisted_runtime_settings = (
-                        await setup_service.get_persisted_runtime_settings(runtime_db)
-                    )
+                    persisted_runtime_settings = await setup_service.get_persisted_runtime_settings(runtime_db)
                 finally:
                     await runtime_db.close()
 

backend/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "bangui-backend"
-version = "0.9.19-rc.4"
+version = "0.9.19-rc.5"
 description = "BanGUI backend — fail2ban web management interface"
 requires-python = ">=3.12"
 dependencies = [

backend/tests/test_db.py

@@ -252,6 +252,30 @@ async def test_cleanup_wal_files_removes_orphaned_files(tmp_path: Path) -> None:
     assert not shm_path.exists()
 
 
+async def test_cleanup_wal_files_skips_recent_files(tmp_path: Path) -> None:
+    """Test that _cleanup_wal_files skips files modified within 10 seconds."""
+    db_path = str(tmp_path / "test_wal_recent.db")
+    wal_path = Path(db_path + "-wal")
+    shm_path = Path(db_path + "-shm")
+
+    # Create files with recent mtime
+    wal_path.write_text("recent")
+    shm_path.write_text("recent")
+    recent_mtime = time.time() - 5
+    os.utime(wal_path, (recent_mtime, recent_mtime))
+    os.utime(shm_path, (recent_mtime, recent_mtime))
+
+    assert wal_path.exists()
+    assert shm_path.exists()
+
+    # Run cleanup
+    await _cleanup_wal_files(db_path)
+
+    # Files should NOT be removed (recent)
+    assert wal_path.exists()
+    assert shm_path.exists()
+
+
 async def test_cleanup_wal_files_handles_missing_files(tmp_path: Path) -> None:
     """Test that _cleanup_wal_files handles non-existent files gracefully."""
     db_path = str(tmp_path / "nonexistent.db")

backend/tests/test_dependencies.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import aiohttp
+import aiosqlite
 import pytest
 from fastapi import FastAPI
 from starlette.requests import Request
@@ -19,6 +20,13 @@ from app.dependencies import (
     get_settings,
     get_settings_repo,
 )
+from app.exceptions import (
+    DatabaseBusyError,
+    DatabaseCorruptedError,
+    DatabasePathInvalidError,
+    DatabasePermissionDeniedError,
+    DatabaseUnavailableError,
+)
 from app.main import create_app
 from app.models.server import ServerStatus
 
@@ -98,3 +106,184 @@ async def test_get_db_uses_effective_runtime_database_path(test_settings: Settin
             await gen.aclose()
 
     mock_open_db.assert_awaited_once_with("/tmp/runtime.db")
+
+
+# ---------------------------------------------------------------------------
+# Database error handling tests
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_get_db_raises_database_permission_denied_on_permission_error(
+    test_settings: Settings,
+) -> None:
+    """PermissionError from open_db raises DatabasePermissionDeniedError."""
+    with patch(
+        "app.db.open_db",
+        new=AsyncMock(side_effect=DatabasePermissionDeniedError(test_settings.database_path)),
+    ):
+        gen = get_db(settings=test_settings)
+        with pytest.raises(DatabasePermissionDeniedError) as exc_info:
+            await gen.__anext__()
+        await gen.aclose()
+
+    assert exc_info.value.error_code == "database_permission_denied"
+    assert exc_info.value.database_path == test_settings.database_path
+
+
+@pytest.mark.asyncio
+async def test_get_db_raises_database_path_invalid_on_missing_directory(
+    test_settings: Settings,
+) -> None:
+    """sqlite3.OperationalError('unable to open database file') raises DatabasePathInvalidError."""
+    with patch(
+        "app.db.open_db",
+        new=AsyncMock(side_effect=DatabasePathInvalidError(test_settings.database_path)),
+    ):
+        gen = get_db(settings=test_settings)
+        with pytest.raises(DatabasePathInvalidError) as exc_info:
+            await gen.__anext__()
+        await gen.aclose()
+
+    assert exc_info.value.error_code == "database_path_invalid"
+    assert exc_info.value.database_path == test_settings.database_path
+
+
+@pytest.mark.asyncio
+async def test_get_db_retries_on_database_locked(test_settings: Settings) -> None:
+    """get_db retries up to 3 times when database is locked."""
+    mock_connection = MagicMock()
+    mock_connection.close = AsyncMock()
+
+    locked_err = DatabaseUnavailableError(
+        test_settings.database_path, "database is locked"
+    )
+
+    with patch(
+        "app.db.open_db",
+        new=AsyncMock(side_effect=[locked_err, locked_err, mock_connection]),
+    ) as mock_open:
+        gen = get_db(settings=test_settings)
+        with patch("asyncio.sleep", new=AsyncMock()) as mock_sleep:
+            connection = await gen.__anext__()
+            await gen.aclose()
+
+    assert mock_open.call_count == 3
+    assert connection is mock_connection
+    assert mock_sleep.call_count == 2
+
+
+@pytest.mark.asyncio
+async def test_get_db_fails_after_max_retries_on_database_locked(
+    test_settings: Settings,
+) -> None:
+    """After 3 retries on database locked, raises DatabaseBusyError."""
+    locked_err = DatabaseUnavailableError(
+        test_settings.database_path, "database is locked"
+    )
+
+    with patch("app.db.open_db", new=AsyncMock(side_effect=locked_err)) as mock_open:
+        gen = get_db(settings=test_settings)
+        with patch("asyncio.sleep", new=AsyncMock()):
+            with pytest.raises(DatabaseBusyError) as exc_info:
+                await gen.__anext__()
+            await gen.aclose()
+
+    assert mock_open.call_count == 3
+    assert exc_info.value.error_code == "database_busy"
+    assert exc_info.value.retries == 3
+
+
+@pytest.mark.asyncio
+async def test_get_db_raises_database_corrupted_on_malformed_db(
+    test_settings: Settings,
+) -> None:
+    """sqlite3.DatabaseError('database disk image is malformed') raises DatabaseCorruptedError."""
+    with patch(
+        "app.db.open_db",
+        new=AsyncMock(side_effect=DatabaseCorruptedError(test_settings.database_path)),
+    ):
+        gen = get_db(settings=test_settings)
+        with pytest.raises(DatabaseCorruptedError) as exc_info:
+            await gen.__anext__()
+        await gen.aclose()
+
+    assert exc_info.value.error_code == "database_corrupted"
+
+
+@pytest.mark.asyncio
+async def test_open_db_creates_parent_directory_if_missing(tmp_path: pytest.Path) -> None:
+    """open_db creates the parent directory when it does not exist."""
+    from pathlib import Path
+
+    from app.db import open_db
+
+    db_path = str(Path(str(tmp_path)) / "subdir" / "deeper" / "bangui.db")
+    mock_conn = MagicMock()
+    mock_conn.close = AsyncMock()
+    mock_conn.execute = AsyncMock()
+    mock_conn.commit = AsyncMock()
+
+    with patch("aiosqlite.connect", new=AsyncMock(return_value=mock_conn)), \
+         patch("app.db._configure_connection", new=AsyncMock()):
+        connection = await open_db(db_path)
+
+    assert connection is mock_conn
+    assert Path(db_path).parent.exists()
+
+
+@pytest.mark.asyncio
+async def test_open_db_logs_specific_sqlite_error_code() -> None:
+    """open_db logs the SQLite error code when available."""
+    from app.db import open_db
+
+    exc = aiosqlite.OperationalError("database is locked")
+    exc.sqlite_errorcode = 5  # SQLITE_BUSY
+
+    with patch("aiosqlite.connect", new=AsyncMock(side_effect=exc)), \
+         pytest.raises(DatabaseUnavailableError):
+        await open_db("/tmp/test.db")
+
+
+# ---------------------------------------------------------------------------
+# Error metadata tests
+# ---------------------------------------------------------------------------
+
+
+def test_database_busy_error_metadata() -> None:
+    """DatabaseBusyError returns correct metadata."""
+    err = DatabaseBusyError("/data/bangui.db", retries=3)
+    assert err.error_code == "database_busy"
+    metadata = err.get_error_metadata()
+    assert metadata["database_path"] == "/data/bangui.db"
+    assert metadata["retries"] == 3
+
+
+def test_database_permission_denied_error_metadata() -> None:
+    """DatabasePermissionDeniedError returns correct metadata."""
+    err = DatabasePermissionDeniedError("/data/bangui.db")
+    assert err.error_code == "database_permission_denied"
+    assert err.get_error_metadata()["database_path"] == "/data/bangui.db"
+
+
+def test_database_path_invalid_error_metadata() -> None:
+    """DatabasePathInvalidError returns correct metadata."""
+    err = DatabasePathInvalidError("/data/bangui.db")
+    assert err.error_code == "database_path_invalid"
+    assert err.get_error_metadata()["database_path"] == "/data/bangui.db"
+
+
+def test_database_corrupted_error_metadata() -> None:
+    """DatabaseCorruptedError returns correct metadata."""
+    err = DatabaseCorruptedError("/data/bangui.db")
+    assert err.error_code == "database_corrupted"
+    assert err.get_error_metadata()["database_path"] == "/data/bangui.db"
+
+
+def test_database_unavailable_error_metadata() -> None:
+    """DatabaseUnavailableError returns correct metadata."""
+    err = DatabaseUnavailableError("/data/bangui.db", "some error")
+    assert err.error_code == "database_unavailable"
+    metadata = err.get_error_metadata()
+    assert metadata["database_path"] == "/data/bangui.db"
+    assert metadata["error"] == "some error"

backend/tests/test_main.py

@@ -2,6 +2,9 @@
 
 import asyncio
 import contextlib
+import io
+import json
+import logging
 from pathlib import Path
 from unittest.mock import AsyncMock, MagicMock, patch
 
@@ -22,6 +25,7 @@ from app.main import (
 from app.middleware.correlation import CorrelationIdMiddleware
 from app.middleware.rate_limit import RateLimitMiddleware
 from app.services import setup_service
+from app.utils.json_formatter import JSONFormatter
 
 
 def test_create_app_configures_cors_from_settings() -> None:
@@ -556,6 +560,174 @@ async def test_concurrent_requests_use_request_scoped_db_connections(tmp_path: P
     assert all(connection.close.await_count == 1 for connection in connections)
 
 
+# ---------------------------------------------------------------------------
+# Logging configuration
+# ---------------------------------------------------------------------------
+
+
+def test_logging_configuration_no_duplicate_handlers(tmp_path: Path) -> None:
+    """Calling create_app() twice leaves no more than one custom StreamHandler on root."""
+    fail2ban_config_dir = tmp_path / "fail2ban"
+    fail2ban_config_dir.mkdir()
+
+    settings1 = Settings(
+        database_path=str(tmp_path / "test1.db"),
+        fail2ban_socket="/tmp/fake_fail2ban.sock",
+        fail2ban_config_dir=str(fail2ban_config_dir),
+        session_secret="test-secret-key-do-not-use-in-production",
+        session_duration_minutes=60,
+        timezone="UTC",
+        log_level="debug",
+    )
+
+    create_app(settings=settings1)
+
+    settings2 = Settings(
+        database_path=str(tmp_path / "test2.db"),
+        fail2ban_socket="/tmp/fake_fail2ban.sock",
+        fail2ban_config_dir=str(fail2ban_config_dir),
+        session_secret="test-secret-key-do-not-use-in-production-2",
+        session_duration_minutes=60,
+        timezone="UTC",
+        log_level="debug",
+    )
+
+    create_app(settings=settings2)
+    # _configure_logging uses basicConfig which replaces handlers on the root logger.
+    # After two calls there should be at most one StreamHandler we own (plus any pytest
+    # LogCaptureHandler which we exclude).
+    root_stream_handlers = [
+        h for h in logging.getLogger().handlers
+        if isinstance(h, logging.StreamHandler) and not type(h).__name__.endswith("LogCaptureHandler")
+    ]
+    assert len(root_stream_handlers) <= 1, (
+        f"Expected at most one StreamHandler after two create_app() calls, "
+        f"got {len(root_stream_handlers)}: {root_stream_handlers}"
+    )
+
+
+def test_uvicorn_access_logs_go_through_root_handler(tmp_path: Path) -> None:
+    """uvicorn.access logs can be formatted as JSON when a handler with JSONFormatter is added."""
+    fail2ban_config_dir = tmp_path / "fail2ban"
+    fail2ban_config_dir.mkdir()
+
+    settings = Settings(
+        database_path=str(tmp_path / "test.db"),
+        fail2ban_socket="/tmp/fake_fail2ban.sock",
+        fail2ban_config_dir=str(fail2ban_config_dir),
+        session_secret="test-secret-key-do-not-use-in-production",
+        session_duration_minutes=60,
+        timezone="UTC",
+        log_level="debug",
+    )
+    create_app(settings=settings)
+
+    # uvicorn.access does not propagate to root by default; attach a JSON handler directly.
+    uvicorn_access = logging.getLogger("uvicorn.access")
+    output = io.StringIO()
+    handler = logging.StreamHandler(stream=output)
+    handler.setFormatter(JSONFormatter())
+    uvicorn_access.addHandler(handler)
+
+    try:
+        uvicorn_access.setLevel(logging.DEBUG)
+        uvicorn_access.info("GET /api/v1/health 200")
+        line = output.getvalue().strip()
+        assert line, "Expected non-empty log output from uvicorn.access"
+        parsed = json.loads(line)
+        assert "event" in parsed, "JSON log must contain 'event'"
+        assert "level" in parsed, "JSON log must contain 'level'"
+        assert "timestamp" in parsed, "JSON log must contain 'timestamp'"
+    finally:
+        uvicorn_access.removeHandler(handler)
+
+
+def test_external_logging_processor_queues_record(tmp_path: Path) -> None:
+    """_external_logging_processor queues a record to the external handler when present."""
+    from app.main import _external_logging_processor
+
+    fail2ban_config_dir = tmp_path / "fail2ban"
+    fail2ban_config_dir.mkdir()
+
+    settings = Settings(
+        database_path=str(tmp_path / "test.db"),
+        fail2ban_socket="/tmp/fake_fail2ban.sock",
+        fail2ban_config_dir=str(fail2ban_config_dir),
+        session_secret="test-secret-key-do-not-use-in-production",
+        session_duration_minutes=60,
+        timezone="UTC",
+        log_level="debug",
+    )
+    create_app(settings=settings)
+
+    from app.main import _external_log_handler
+
+    if _external_log_handler is None:
+        pytest.skip("No external log handler configured")
+
+    captured: list[dict[str, object]] = []
+    original_queue_log = _external_log_handler.queue_log
+
+    def mock_queue_log(record: dict[str, object]) -> None:
+        captured.append(record)
+
+    _external_log_handler.queue_log = mock_queue_log
+
+    try:
+        record = logging.makeLogRecord({"msg": "test event", "levelname": "INFO", "name": "test.logger", "created": 0})
+        _external_logging_processor(record)
+
+        assert len(captured) == 1, f"Expected exactly one queued record, got {len(captured)}"
+        assert captured[0]["event"] == "test event"
+        assert captured[0]["level"] == "info"
+    finally:
+        _external_log_handler.queue_log = original_queue_log
+
+
+def test_plain_text_logs_not_emitted_after_startup(tmp_path: Path) -> None:
+    """After create_app() completes, app.db logger output is JSON, not plain text."""
+    fail2ban_config_dir = tmp_path / "fail2ban"
+    fail2ban_config_dir.mkdir()
+
+    settings = Settings(
+        database_path=str(tmp_path / "test.db"),
+        fail2ban_socket="/tmp/fake_fail2ban.sock",
+        fail2ban_config_dir=str(fail2ban_config_dir),
+        session_secret="test-secret-key-do-not-use-in-production",
+        session_duration_minutes=60,
+        timezone="UTC",
+        log_level="debug",
+    )
+    create_app(settings=settings)
+
+    output = io.StringIO()
+    handler = logging.StreamHandler(stream=output)
+    handler.setFormatter(JSONFormatter())
+    db_logger = logging.getLogger("app.db")
+    db_logger.addHandler(handler)
+    db_logger.setLevel(logging.DEBUG)
+
+    try:
+        db_logger.info("test_db_log")
+        line = output.getvalue().strip()
+        assert line, "Expected non-empty log output"
+        assert not line.startswith("test_db_log "), "Log must not be plain text"
+        parsed = json.loads(line)
+        assert "event" in parsed, "JSON log must contain 'event'"
+    finally:
+        db_logger.removeHandler(handler)
+
+    try:
+        db_logger.info("test_db_log")
+        line = output.getvalue().strip()
+        assert line, "Expected non-empty log output"
+        assert not line.startswith("test_db_log "), "Log must not be plain text"
+        parsed = json.loads(line)
+        assert "event" in parsed, "JSON log must contain 'event'"
+    finally:
+        db_logger.removeHandler(handler)
+
+
 # ---------------------------------------------------------------------------
 # Middleware order validation
 # ---------------------------------------------------------------------------

backend/tests/test_services/test_ban_service.py

@@ -934,6 +934,29 @@ class TestBanTrend:
             parsed = datetime.fromisoformat(bucket.timestamp)
             assert parsed.tzinfo is not None  # Must be timezone-aware (UTC)
 
+    async def test_ban_trend_since_is_within_expected_range(self, tmp_path: Path) -> None:
+        """``since`` value is within 24h + 60s slack of the current time."""
+        from app.utils.constants import TIME_RANGE_SLACK_SECONDS
+
+        now = int(time.time())
+        # Place a ban just inside the expected range: 23 hours ago.
+        # With 60s slack, since ≈ now - 24h - 60s, so 23h-ago ban should be included.
+        just_inside_range = now - (23 * 3600)
+        path = str(tmp_path / "test_since_range.sqlite3")
+        await _create_f2b_db(
+            path,
+            [{"jail": "sshd", "ip": "1.2.3.4", "timeofban": just_inside_range}],
+        )
+
+        with patch(
+            "app.services.ban_service.get_fail2ban_db_path",
+            new=AsyncMock(return_value=path),
+        ):
+            result = await ban_service.ban_trend("/fake/sock", "24h")
+
+        # Ban at 23h ago must appear (within 24h + 60s window).
+        assert sum(b.count for b in result.buckets) == 1
+
 
 # ---------------------------------------------------------------------------
 # bans_by_jail

backend/tests/test_services/test_time_utils.py

@@ -134,3 +134,15 @@ class TestSinceUnix:
         # The slack should be ~60 seconds
         assert actual_slack >= TIME_RANGE_SLACK_SECONDS - 1
         assert actual_slack <= TIME_RANGE_SLACK_SECONDS + 1
+
+    def test_since_unix_returns_utc_epoch(self) -> None:
+        """``since_unix('24h')`` returns a value within 24h + 60s of ``time.time()``."""
+        before = int(time.time())
+        result = since_unix("24h")
+        after = int(time.time())
+
+        # Allow 2 second tolerance for execution time
+        expected_min = before - (24 * 3600) - TIME_RANGE_SLACK_SECONDS - 2
+        expected_max = after - (24 * 3600) - TIME_RANGE_SLACK_SECONDS + 2
+
+        assert expected_min <= result <= expected_max