lib.App: Make default log values overridable

The __init__() method reads default log configuration directly
from environment variables, making it impossible for subclasses to
change defaults.

Extract the defaults into _default_log_flags(), _default_log_level(),
_default_log_file(), and _default_show_backtrace() methods, then call
them from __init__(). Subclasses can now override these methods to
customize defaults without needing to override the entire __init__()
method.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/App.py

@@ -9,7 +9,19 @@ from argparse import ArgumentDefaultsHelpFormatter, ArgumentParser, Namespace
 from typing import Any, cast, override, TYPE_CHECKING
 
 from .AsyncRunner import AsyncRunner
-from .log import DEBUG, ERR, NOTICE, log, log_m, set_log_flags, set_log_level
+from .log import (
+    DEBUG,
+    ERR,
+    NOTICE,
+    LogFlag,
+    log,
+    log_m,
+    parse_log_flags,
+    parse_log_level,
+    set_log_flags,
+    set_log_level
+)
+
 from .Types import LoadTypes
 from .util import pretty_cmd
 
@@ -46,15 +58,27 @@ class App:  # export
     def _default_log_flags_env(self) -> str:
         return 'JW_DEFAULT_LOG_FLAGS'
 
+    def _default_log_flags(self, default: LogFlag) -> LogFlag:
+        return default
+
     def _default_log_level_env(self) -> str:
         return 'JW_DEFAULT_LOG_LEVEL'
 
+    def _default_log_level(self, default: int) -> int:
+        return default
+
     def _default_log_file_env(self) -> str:
         return 'JW_DEFAULT_LOG_FILE'
 
+    def _default_log_file(self, default: str | None) -> str | None:
+        return default
+
     def _default_show_backtrace_env(self) -> str:
         return 'JW_DEFAULT_SHOW_BACKTRACE'
 
+    def _default_show_backtrace(self, default: bool) -> bool:
+        return default
+
     def __init__(
         self,
         description: str = '',
@@ -125,20 +149,25 @@ class App:  # export
 
         self.__args: Namespace | None = None
         self.__cmdline: str | None = None
-        self.__default_log_flags: str = os.getenv(
-            self._default_log_flags_env(), default = 'stderr,position,prio,color'
+
+        self.__default_log_flags = self._default_log_flags(
+            LogFlag.STDERR | LogFlag.POSITION | LogFlag.PRIO | LogFlag.COLOR
         )
-        self.__default_log_level: str | int | None = os.getenv(
-            self._default_log_level_env(), default = NOTICE
-        )
-        self.__default_log_file: str | None = os.getenv(
-            self._default_log_file_env(), default = None
-        )
-        backtrace: str | bool = os.getenv(self._default_show_backtrace_env(), False)
-        self.__back_trace = isinstance(backtrace, str) and backtrace.lower() in {
-            '1',
-            'true',
-        }
+        if (env := os.getenv(self._default_log_flags_env(), None)) is not None:
+            self.__default_log_flags = parse_log_flags(env)
+
+        self.__default_log_level = self._default_log_level(NOTICE)
+        if (env := os.getenv(self._default_log_level_env(), None)) is not None:
+            self.__default_log_level = parse_log_level(env)
+
+        self.__default_log_file = self._default_log_file(None)
+        if (env := os.getenv(self._default_log_file_env(), None)) is not None:
+            self.__default_log_file = env
+
+        self.__back_trace = self._default_show_backtrace(False)
+        if (env := os.getenv(self._default_show_backtrace_env())) is not None:
+            self.__back_trace = env.lower() in ['1', 'true']
+
         set_log_flags(self.__default_log_flags)
         set_log_level(self.__default_log_level)
 

test/integration/jw-pkg/help/test-expected.txt

@@ -11,7 +11,7 @@ jw-pkg swiss army knife
 
 options:
   --log-flags LOG_FLAGS
-                        Log flags (default: stderr,position,prio,color)
+                        Log flags (default: color,position,prio,stderr)
   --log-level LOG_LEVEL
                         Log level (default: 5)
   --log-file LOG_FILE   Log file (default: None)