Add CLI arguments for enabling the development logger and setting logging level

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
  * Added the `-p`/`--include-path` CLI command to prepend entries to the `sys.path` as an alternative to `PYTHONPATH` (#1027)
  * Added an empty entry to `sys.path` for all CLI entrypoints (`basilisp run`, `basilisp repl`, etc.) (#1027)
+ * Added command line arguments for enabling the development logger and configuring the logging level (#1047)
 
 ### Changed
  * The compiler will no longer require `Var` indirection for top-level `do` forms unless those forms specify `^:use-var-indirection` metadata (which currently is only used in the `ns` macro) (#1034)

src/basilisp/cli.py

@@ -281,6 +281,32 @@ def _add_debug_arg_group(parser: argparse.ArgumentParser) -> None:
             "(env: BASILISP_DO_NOT_CACHE_NAMESPACES; default: false)"
         ),
     )
+    group.add_argument(
+        "--enable-logger",
+        action=_set_envvar_action(
+            "BASILISP_USE_DEV_LOGGER", parent=argparse._StoreAction
+        ),
+        nargs="?",
+        const=True,
+        type=_to_bool,
+        help=(
+            "if true, enable the Basilisp root logger "
+            "(env: BASILISP_USE_DEV_LOGGER; default: false)"
+        ),
+    )
+    group.add_argument(
+        "-l",
+        "--log-level",
+        action=_set_envvar_action(
+            "BASILISP_LOGGING_LEVEL", parent=argparse._StoreAction
+        ),
+        type=lambda s: s.upper(),
+        default="WARNING",
+        help=(
+            "the logging level for logs emitted by the Basilisp compiler and runtime "
+            "(env: BASILISP_LOGGING_LEVEL; default: WARNING)"
+        ),
+    )
 
 
 def _add_import_arg_group(parser: argparse.ArgumentParser) -> None:

src/basilisp/logconfig.py

@@ -1,30 +1,41 @@
 import logging
 import os
+from typing import Optional
+
+TRACE = 5
+
+logging.addLevelName(TRACE, "TRACE")
+
+
+DEFAULT_FORMAT = (
+    "%(asctime)s %(levelname)s [%(name)s.%(funcName)s:%(lineno)d] - %(message)s"
+)
 
 
 def get_level() -> str:
     """Get the default logging level for Basilisp."""
     return os.getenv("BASILISP_LOGGING_LEVEL", "WARNING")
 
 
-def get_handler(level: str, fmt: str) -> logging.Handler:
+def get_handler(
+    level: Optional[str] = None, fmt: str = DEFAULT_FORMAT
+) -> logging.Handler:
     """Get the default logging handler for Basilisp."""
     handler = (
         logging.StreamHandler()
         if os.getenv("BASILISP_USE_DEV_LOGGER", "").lower() == "true"
         else logging.NullHandler()
     )
     handler.setFormatter(logging.Formatter(fmt))
-    handler.setLevel(level)
+    handler.setLevel(level or get_level())
     return handler
 
 
-TRACE = 5
-
-logging.addLevelName(TRACE, "TRACE")
-
-DEFAULT_FORMAT = (
-    "%(asctime)s %(levelname)s [%(name)s.%(funcName)s:%(lineno)d] - %(message)s"
-)
-DEFAULT_LEVEL = get_level()
-DEFAULT_HANDLER = get_handler(DEFAULT_LEVEL, DEFAULT_FORMAT)
+def configure_root_logger(
+    level: Optional[str] = None, fmt: str = DEFAULT_FORMAT
+) -> None:
+    """Configure the Basilisp root logger."""
+    level = level or get_level()
+    logger = logging.getLogger("basilisp")
+    logger.setLevel(level)
+    logger.addHandler(get_handler(level=level, fmt=fmt))

src/basilisp/main.py

@@ -1,19 +1,14 @@
 import importlib
-import logging
 import site
 from pathlib import Path
 from typing import List, Optional
 
 from basilisp import importer as importer
+from basilisp import logconfig
 from basilisp.lang import runtime as runtime
 from basilisp.lang.compiler import compiler_opts
 from basilisp.lang.typing import CompilerOpts
 from basilisp.lang.util import munge
-from basilisp.logconfig import DEFAULT_HANDLER, DEFAULT_LEVEL
-
-logger = logging.getLogger("basilisp")
-logger.setLevel(DEFAULT_LEVEL)
-logger.addHandler(DEFAULT_HANDLER)
 
 
 def init(opts: Optional[CompilerOpts] = None) -> None:
@@ -27,6 +22,7 @@ def init(opts: Optional[CompilerOpts] = None) -> None:
     If you want to execute a Basilisp file which is stored in a well-formed package
     or module structure, you probably want to use :py:func:`bootstrap`.
     """
+    logconfig.configure_root_logger()
     runtime.init_ns_var()
     runtime.bootstrap_core(opts if opts is not None else compiler_opts())
     importer.hook_imports()