feat: Lint type annotations using mypy (#311)

* fix: Type annotation issues detected by mypy

* feat: Lint type annotations using mypy

.pre-commit-config.yaml

@@ -18,6 +18,15 @@ repos:
         stages: [commit]
         types: [python]
 
+      - id: mypy
+        name: mypy
+        entry: mypy
+        args: [--no-incremental]
+        language: system
+        stages: [commit]
+        types: [python]
+        require_serial: true
+
       - id: pylint
         name: pylint
         entry: pylint

linz_logger/logger.py

@@ -3,6 +3,7 @@
 from enum import Enum
 from functools import partial
 from platform import node
+from typing import Any, MutableMapping
 
 import structlog
 from structlog.contextvars import bind_contextvars, clear_contextvars, merge_contextvars, unbind_contextvars
@@ -27,7 +28,7 @@ class LogLevel(Enum):
 
 
 current_level = LogLevel.debug
-structlog.PrintLogger.trace = structlog.PrintLogger.msg
+structlog.PrintLogger.trace = structlog.PrintLogger.msg  # type: ignore[attr-defined]
 pid = os.getpid()
 hostname = node()
 ulid = str(ULID())
@@ -61,7 +62,7 @@ def remove_contextvars(keys):
     unbind_contextvars(*keys)
 
 
-def level_filter(_, __, event_dict: dict):
+def level_filter(_, __, event_dict: MutableMapping[str, Any]):
     """
     Silently drop logs lower than the set level.
     """
@@ -73,7 +74,7 @@ def level_filter(_, __, event_dict: dict):
 # This is a standard format for the function so it needs all three arguments
 # Even thought we do not use them
 # pylint: disable=unused-argument
-def add_default_keys(current_logger, method_name: str, event_dict: dict):
+def add_default_keys(current_logger, method_name: str, event_dict: MutableMapping[str, Any]):
     """
     Configure structlog to output the same format as pinojs
     {

pyproject.toml

@@ -19,6 +19,7 @@ python-ulid = "^1.1.0"
 [tool.poetry.group.dev.dependencies]
 black = "^24.1.1"
 isort = "^5.13.1"
+mypy = "*"
 pre-commit = "*"
 pylint = "^3.0.2"
 pytest = ">=7.4.4,<9.0.0"