feat: implement logzero functionality directly

The logzero package provides a nice simple default logger setup. However
it's currently unmaintained and so we don't really want to depend on it.

This commit implements the main functionality we used from it so that we
can remove the dependency.

Signed-off-by: James McCorrie <james.mccorrie@lowrisc.org>

Author: machshev

pyproject.toml

@@ -22,7 +22,6 @@ dependencies = [
     "gitpython>=3.1.45",
     "hjson>=3.1.0",
     "jinja2>=3.1.6",
-    "logzero>=1.7.0",
     "psutil>=7.2.2",
     "pydantic>=2.9.2",
     "pyyaml>=6.0.2",

scripts/license_check.py

@@ -5,11 +5,12 @@
 
 """Check all files for license header."""
 
+import logging
 import subprocess
 import sys
 from pathlib import Path
 
-from logzero import logger
+logger = logging.getLogger(__name__)
 
 LICENSE = (
     "Copyright lowRISC contributors (OpenTitan project).",
@@ -36,7 +37,7 @@
 
 
 def check_header(*, text: str, trailing_newline_optional: bool = False) -> bool:
-    """Check header complies with license requirmeents."""
+    """Check header complies with license requirements."""
     lines = text.splitlines()
 
     try:
@@ -92,6 +93,6 @@ def check_header(*, text: str, trailing_newline_optional: bool = False) -> bool:
         failed.append(path)
 
 for path in failed:
-    logger.error(f"failed: {path}")
+    logger.error("failed: %s", path)
 
 sys.exit(min(len(failed), 255))

src/dvsim/logging.py

@@ -5,18 +5,44 @@
 """Logging config."""
 
 import logging
+import sys
 from pathlib import Path
 from typing import cast
 
-from logzero import DEFAULT_FORMAT, setup_logger
-
 __all__ = (
     "configure_logging",
     "LOG_LEVELS",
 )
 
 
 LOG_LEVELS = ["DEBUG", "VERBOSE", "INFO", "WARNING", "ERROR", "CRITICAL"]
+DEFAULT_FORMAT = (
+    "%(color)s[%(levelname)1.1s %(asctime)s %(module)s:%(lineno)d]%(end_color)s %(message)s"
+)
+_PLAIN_FORMAT = "[%(levelname)1.1s %(asctime)s %(module)s:%(lineno)d] %(message)s"
+_DATE_FORMAT = "%y%m%d %H:%M:%S"
+
+_VERBOSE_LOG_LEVEL = 15
+
+# ANSI color codes keyed by level
+_LEVEL_COLORS = {
+    logging.DEBUG: "\033[36m",  # Cyan
+    _VERBOSE_LOG_LEVEL: "\033[34m",  # Blue  (VERBOSE)
+    logging.INFO: "\033[32m",  # Green
+    logging.WARNING: "\033[33m",  # Yellow
+    logging.ERROR: "\033[31m",  # Red
+    logging.CRITICAL: "\033[31;1m",  # Bold red
+}
+_RESET = "\033[0m"
+
+
+class _ColorFormatter(logging.Formatter):
+    """Formatter that injects %(color)s / %(end_color)s into records."""
+
+    def format(self, record: logging.LogRecord) -> str:
+        record.color = _LEVEL_COLORS.get(record.levelno, "")
+        record.end_color = _RESET if record.color else ""
+        return super().format(record)
 
 
 class DVSimLogger(logging.getLoggerClass()):
@@ -27,7 +53,7 @@ class DVSimLogger(logging.getLoggerClass()):
     ERROR = logging.ERROR
     WARNING = logging.WARNING
     INFO = logging.INFO
-    VERBOSE = 15
+    VERBOSE = _VERBOSE_LOG_LEVEL
     DEBUG = logging.DEBUG
 
     def __init__(self, name: str) -> None:
@@ -49,20 +75,36 @@ def set_logfile(
     ) -> None:
         """Set a logfile to save the logs to."""
         fh = logging.FileHandler(filename=path, mode=mode)
-
-        fh.setLevel(level or self.DEBUG)
-        fh.setFormatter(
-            logging.Formatter(DEFAULT_FORMAT),
-        )
-
+        fh.setLevel(level if level is not None else self.DEBUG)
+        fh.setFormatter(logging.Formatter(_PLAIN_FORMAT, datefmt=_DATE_FORMAT))
         self.addHandler(fh)
 
 
 def _build_logger() -> DVSimLogger:
     """Build a DVSim logger."""
     logging.setLoggerClass(DVSimLogger)
 
-    return cast("DVSimLogger", setup_logger("dvsim"))
+    logger = cast("DVSimLogger", logging.getLogger("dvsim"))
+
+    # Attach a stderr handler with colour formatting (mirrors logzero default)
+    if not logger.handlers:
+        sh = logging.StreamHandler(sys.stderr)
+        sh.setFormatter(_ColorFormatter(DEFAULT_FORMAT, datefmt=_DATE_FORMAT))
+        logger.addHandler(sh)
+
+    # Prevent log records bubbling up to the root logger
+    logger.propagate = False
+
+    # Log any unhandled exceptions
+    _previous_excepthook = sys.excepthook
+
+    def _handle_exception(exc_type, exc_value, exc_tb):
+        logger.critical("Unhandled exception", exc_info=(exc_type, exc_value, exc_tb))
+        _previous_excepthook(exc_type, exc_value, exc_tb)
+
+    sys.excepthook = _handle_exception
+
+    return logger
 
 
 # Logger to import
@@ -94,5 +136,5 @@ def configure_logging(*, verbose: bool, debug: bool, log_level: str | None, log_
     if log_file:
         log.set_logfile(
             path=Path(log_file),
-            level=log_level,
+            level=new_log_level,
         )