refine logging (#38)

* refine logging

src/fillname/__main__.py

@@ -2,7 +2,9 @@
 The main entry point for the application.
 """
 
-from .utils.logger import setup_logger
+import sys
+
+from .utils.logging import configure_logging, get_logger
 from .utils.parser import get_parser
 
 
@@ -12,8 +14,9 @@ def main() -> None:
     """
     parser = get_parser()
     args = parser.parse_args()
-    log = setup_logger("main", args.log)
+    configure_logging(sys.stderr, args.log, sys.stderr.isatty())
 
+    log = get_logger("main")
     log.info("info")
     log.warning("warning")
     log.debug("debug")

src/fillname/utils/logging.py

@@ -0,0 +1,79 @@
+"""
+Setup project wide loggers.
+
+This is a thin wrapper around Python's logging module. It supports colored
+logging.
+"""
+
+import logging
+from typing import TextIO
+
+NOTSET = logging.NOTSET
+DEBUG = logging.DEBUG
+INFO = logging.INFO
+WARNING = logging.WARNING
+ERROR = logging.ERROR
+CRITICAL = logging.CRITICAL
+
+COLORS = {
+    "GREY": "\033[90m",
+    "BLUE": "\033[94m",
+    "GREEN": "\033[92m",
+    "YELLOW": "\033[93m",
+    "RED": "\033[91m",
+    "NORMAL": "\033[0m",
+}
+
+
+class SingleLevelFilter(logging.Filter):
+    """
+    Filter levels.
+    """
+
+    passlevel: int
+    reject: bool
+
+    def __init__(self, passlevel: int, reject: bool):
+        # pylint: disable=super-init-not-called
+        self.passlevel = passlevel
+        self.reject = reject
+
+    def filter(self, record: logging.LogRecord) -> bool:
+        if self.reject:
+            return record.levelno != self.passlevel  # nocoverage
+
+        return record.levelno == self.passlevel
+
+
+def configure_logging(stream: TextIO, level: int, use_color: bool) -> None:
+    """
+    Configure application logging.
+    """
+
+    def format_str(color: str) -> str:
+        if use_color:
+            return f"{COLORS[color]}%(levelname)s:{COLORS['GREY']}  - %(message)s{COLORS['NORMAL']}"
+        return "%(levelname)s:  - %(message)s"  # nocoverage
+
+    def make_handler(level: int, color: str) -> "logging.StreamHandler[TextIO]":
+        handler = logging.StreamHandler(stream)
+        handler.addFilter(SingleLevelFilter(level, False))
+        handler.setLevel(level)
+        formatter = logging.Formatter(format_str(color))
+        handler.setFormatter(formatter)
+        return handler
+
+    handlers = [
+        make_handler(logging.INFO, "GREEN"),
+        make_handler(logging.WARNING, "YELLOW"),
+        make_handler(logging.DEBUG, "BLUE"),
+        make_handler(logging.ERROR, "RED"),
+    ]
+    logging.basicConfig(handlers=handlers, level=level)
+
+
+def get_logger(name: str) -> logging.Logger:
+    """
+    Get a logger with the given name.
+    """
+    return logging.getLogger(name)

src/fillname/utils/parser.py

@@ -2,12 +2,13 @@
 The command line parser for the project.
 """
 
-import logging
 import sys
 from argparse import ArgumentParser
 from textwrap import dedent
 from typing import Any, Optional, cast
 
+from . import logging
+
 __all__ = ["get_parser"]
 
 if sys.version_info[1] < 8:
@@ -31,7 +32,6 @@ def get_parser() -> ArgumentParser:
             """
         ),
     )
-
     levels = [
         ("error", logging.ERROR),
         ("warning", logging.WARNING),

tests/test_main.py

@@ -2,11 +2,11 @@
 Test cases for main application functionality.
 """
 
-import logging
 from io import StringIO
 from unittest import TestCase
 
-from fillname.utils.logger import setup_logger
+from fillname.utils import logging
+from fillname.utils.logging import configure_logging, get_logger
 from fillname.utils.parser import get_parser
 
 
@@ -19,11 +19,9 @@ def test_logger(self) -> None:
         """
         Test the logger.
         """
-        log = setup_logger("global", logging.INFO)
         sio = StringIO()
-        for handler in log.handlers:
-            assert isinstance(handler, logging.StreamHandler)
-            handler.setStream(sio)
+        configure_logging(sio, logging.INFO, True)
+        log = get_logger("main")
         log.info("test123")
         self.assertRegex(sio.getvalue(), "test123")