refactor(logging): replace structlog with stdlib logging compat layer

- Remove structlog dependency from backend/pyproject.toml
- Add app.utils.logging_compat shim for keyword-arg logging API
- Add app.utils.json_formatter for JSON log output with extra fields
- Update all backend modules to use logging_compat.get_logger()
- Update docstrings in log_sanitizer.py and json_formatter.py
- Update test comment in test_async_utils.py
- Record 406 failing tests in Docs/Tasks.md for tracking

backend/app/services/action_config_service.py

@@ -15,7 +15,7 @@ import re
 import tempfile
 from pathlib import Path
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import (
     ActionAlreadyExistsError,
@@ -47,7 +47,7 @@ from app.utils.config_file_utils import (
 )
 from app.utils.jail_socket import reload_all
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Internal wrappers for shared config helpers.

backend/app/services/auth_service.py

@@ -13,7 +13,7 @@ import secrets
 from typing import TYPE_CHECKING
 
 import bcrypt
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.utils.async_utils import run_blocking
 
@@ -28,7 +28,7 @@ from app.repositories import settings_repo as default_settings_repo
 from app.utils.constants import SESSION_TOKEN_BYTES, SESSION_TOKEN_SIGNATURE_SEPARATOR
 from app.utils.time_utils import add_minutes, utc_now
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # Settings key for password hash
 _KEY_PASSWORD_HASH = "master_password_hash"

backend/app/services/ban_service.py

@@ -16,7 +16,7 @@ import ipaddress
 from typing import TYPE_CHECKING, Any, cast
 
 import aiohttp
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import JailNotFoundError, JailOperationError
 from app.models._common import (
@@ -69,7 +69,7 @@ if TYPE_CHECKING:
     from app.repositories.protocols import HistoryArchiveRepository
     from app.services.geo_cache import GeoCache
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 async def get_fail2ban_db_path(socket_path: str) -> str:

backend/app/services/blocklist_ban_executor.py

@@ -8,14 +8,14 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import JailNotFoundError, JailOperationError
 
 if TYPE_CHECKING:
     from collections.abc import Awaitable, Callable
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 class BanExecutor:

backend/app/services/blocklist_downloader.py

@@ -10,9 +10,9 @@ from __future__ import annotations
 import asyncio
 
 import aiohttp
-import structlog
+from app.utils.logging_compat import get_logger
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 #: HTTP status codes that should be retried for blocklist downloads.
 _BLOCKLIST_HTTP_RETRY_STATUSES: frozenset[int] = frozenset({429, 500, 502, 503, 504})

backend/app/services/blocklist_import_workflow.py

@@ -16,7 +16,7 @@ from typing import TYPE_CHECKING
 
 import aiohttp
 import aiosqlite
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.models.blocklist import BlocklistSource, ImportSourceResult
 from app.repositories import import_run_repo
@@ -29,7 +29,7 @@ if TYPE_CHECKING:
 
     from app.services.geo_cache import GeoCache
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 #: fail2ban jail name for blocklist-origin bans.
 BLOCKLIST_JAIL: str = "blocklist-import"

backend/app/services/blocklist_parser.py

@@ -6,11 +6,11 @@ or CIDR networks. Separates valid IPs from invalid/CIDR entries.
 
 from __future__ import annotations
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.utils.ip_utils import is_valid_ip, is_valid_network, normalise_ip
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 class ParsedBlocklist:

backend/app/services/blocklist_service.py

@@ -19,7 +19,7 @@ from typing import TYPE_CHECKING
 
 import aiohttp
 import aiosqlite
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import BlocklistSourceHasLogsError
 from app.models.blocklist import (
@@ -47,7 +47,7 @@ if TYPE_CHECKING:
     from app.config import Settings
     from app.services.geo_cache import GeoCache
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 #: Settings key used to persist the schedule config.
 _SCHEDULE_SETTINGS_KEY: str = "blocklist_schedule"

backend/app/services/config_service.py

@@ -17,7 +17,7 @@ import contextlib
 import re
 from typing import TYPE_CHECKING, TypeVar, cast
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.utils.fail2ban_client import Fail2BanCommand, Fail2BanToken
 
@@ -59,7 +59,7 @@ from app.utils.fail2ban_response import (
 )
 from app.utils.path_utils import validate_log_target
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Custom exceptions

backend/app/services/dns_validated_connector.py

@@ -23,14 +23,14 @@ import ipaddress
 import socket
 from typing import TYPE_CHECKING
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.utils.ip_utils import is_private_ip
 
 if TYPE_CHECKING:
     from collections.abc import Callable
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 def create_dns_validated_socket_factory() -> (

backend/app/services/fail2ban_metadata_service.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import asyncio
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.utils.constants import FAIL2BAN_SOCKET_TIMEOUT_FAST
 from app.utils.fail2ban_client import (
@@ -13,7 +13,7 @@ from app.utils.fail2ban_client import (
     Fail2BanProtocolError,
 )
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 class Fail2BanMetadataService:

backend/app/services/filter_config_service.py

@@ -13,7 +13,7 @@ import re
 import tempfile
 from pathlib import Path
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import (
     ConfigWriteError,
@@ -48,7 +48,7 @@ from app.utils.config_file_utils import (
 from app.utils.jail_socket import reload_all
 from app.utils.regex_validator import RegexTimeoutError, validate_regex_pattern
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Internal wrappers for shared config helpers.

backend/app/services/geo_cache.py

@@ -21,7 +21,7 @@ import time
 from typing import TYPE_CHECKING
 
 import aiohttp
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.models.geo import GeoInfo
 from app.repositories import geo_cache_repo
@@ -33,7 +33,7 @@ if TYPE_CHECKING:
     import geoip2.database
     import geoip2.errors
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Constants
@@ -208,9 +208,9 @@ class GeoCache:
         Returns:
             A dict with ``resolved`` and ``total`` counts.
         """
-        import structlog  # noqa: PLC0415
+        from app.utils.logging_compat import get_logger
 
-        log = structlog.get_logger()
+        log = get_logger(__name__)
         unresolved = await self.get_unresolved_ips(db)
         if not unresolved:
             return {"resolved": 0, "total": 0}

backend/app/services/health_service.py

@@ -13,7 +13,7 @@ import asyncio
 from collections.abc import Awaitable, Callable
 from typing import TypeVar, cast
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app import __version__
 from app.models.config_domain import DomainServiceStatus
@@ -30,7 +30,7 @@ from app.utils.fail2ban_response import (
     to_dict,
 )
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Internal helpers

backend/app/services/history_service.py

@@ -13,7 +13,7 @@ from __future__ import annotations
 from datetime import UTC, datetime
 from typing import TYPE_CHECKING
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 if TYPE_CHECKING:
     import aiohttp
@@ -37,7 +37,7 @@ from app.utils.constants import DEFAULT_PAGE_SIZE
 from app.utils.fail2ban_db_utils import parse_data_json, ts_to_iso
 from app.utils.time_utils import since_unix
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Internal Helpers

backend/app/services/jail_config_service.py

@@ -16,7 +16,7 @@ import tempfile
 from pathlib import Path
 from typing import TYPE_CHECKING, cast
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import (
     ConfigWriteError,
@@ -59,7 +59,7 @@ if TYPE_CHECKING:
 
     from app.services.protocols import HealthProbe
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 def _parse_jails_sync(config_dir: Path) -> tuple[dict[str, dict[str, str]], dict[str, str]]:

backend/app/services/jail_service.py

@@ -20,7 +20,7 @@ import contextlib
 import ipaddress
 from typing import TYPE_CHECKING, cast
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import JailNotFoundError, JailOperationError
 from app.models.ban_domain import DomainActiveBan
@@ -61,7 +61,7 @@ if TYPE_CHECKING:
     from app.models.geo import GeoEnricher, GeoInfo
     from app.services.geo_cache import GeoCache
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 __all__ = ["reload_all"]
 

backend/app/services/log_service.py

@@ -9,7 +9,7 @@ import asyncio
 import re
 from pathlib import Path
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import ConfigOperationError
 from app.models.config import (
@@ -29,7 +29,7 @@ from app.utils.fail2ban_client import (
 )
 from app.utils.fail2ban_response import ok
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 _NON_FILE_LOG_TARGETS: frozenset[str] = frozenset(
     {"STDOUT", "STDERR", "SYSLOG", "SYSTEMD-JOURNAL"}

backend/app/services/raw_config_io_service.py

@@ -19,7 +19,7 @@ import configparser
 import re
 from typing import TYPE_CHECKING
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import (
     ConfigFileNameError,
@@ -59,7 +59,7 @@ if TYPE_CHECKING:
         JailFileConfigUpdate,
     )
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # ---------------------------------------------------------------------------
 # Internal helpers — INI parsing / patching

backend/app/services/server_service.py

@@ -12,7 +12,7 @@ from __future__ import annotations
 
 from typing import cast
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.exceptions import Fail2BanConnectionError, Fail2BanProtocolError, ServerOperationError
 from app.models.server import ServerSettingsUpdate
@@ -28,7 +28,7 @@ from app.utils.fail2ban_response import ok
 type Fail2BanSettingValue = str | int | bool
 """Allowed values for server settings commands."""
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 
 def _to_int(value: object | None, default: int) -> int:

backend/app/services/settings_service.py

@@ -8,14 +8,14 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.repositories import settings_repo
 
 if TYPE_CHECKING:  # pragma: no cover
     import aiosqlite
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 _KEY_MAP_COLOR_THRESHOLD_HIGH = "map_color_threshold_high"
 _KEY_MAP_COLOR_THRESHOLD_MEDIUM = "map_color_threshold_medium"

backend/app/services/setup_service.py

@@ -11,7 +11,7 @@ from pathlib import Path
 from typing import TYPE_CHECKING
 
 import bcrypt
-import structlog
+from app.utils.logging_compat import get_logger
 
 from app.db import init_db, open_db
 from app.repositories import settings_repo as default_settings_repo
@@ -23,7 +23,7 @@ if TYPE_CHECKING:
     from app.repositories.protocols import SettingsRepository
     from app.services.protocols import Fail2BanMetadataService
 
-log: structlog.stdlib.BoundLogger = structlog.get_logger()
+log = get_logger(__name__)
 
 # Keys used in the settings table.
 _KEY_PASSWORD_HASH = "master_password_hash"