main: improve console output

pyproject.toml

@@ -114,6 +114,7 @@ xfail_strict = true
 junit_family = "xunit2"
 norecursedirs = "tests/integration/*"
 markers = [
+  "contextvars",
   "isolated",
   "pypy3323bug",
   "network",

src/build/__main__.py

@@ -4,6 +4,7 @@
 
 import argparse
 import contextlib
+import contextvars
 import os
 import platform
 import shutil
@@ -20,7 +21,7 @@
 
 import build
 
-from . import ProjectBuilder
+from . import ProjectBuilder, _ctx
 from ._exceptions import BuildBackendException, BuildException, FailedProcessError
 from ._types import ConfigSettings, Distribution, StrPath
 from .env import DefaultIsolatedEnv
@@ -38,21 +39,21 @@
 _NO_COLORS = {color: '' for color in _COLORS}
 
 
-def _init_colors() -> dict[str, str]:
+_styles = contextvars.ContextVar('_styles', default=_COLORS)
+
+
+def _init_colors() -> None:
     if 'NO_COLOR' in os.environ:
         if 'FORCE_COLOR' in os.environ:
             warnings.warn('Both NO_COLOR and FORCE_COLOR environment variables are set, disabling color', stacklevel=2)
-        return _NO_COLORS
+        _styles.set(_NO_COLORS)
     elif 'FORCE_COLOR' in os.environ or sys.stdout.isatty():
-        return _COLORS
-    return _NO_COLORS
-
+        return
+    _styles.set(_NO_COLORS)
 
-_STYLES = _init_colors()
 
-
-def _cprint(fmt: str = '', msg: str = '') -> None:
-    print(fmt.format(msg, **_STYLES), flush=True)
+def _cprint(fmt: str = '', msg: str = '', file: TextIO | None = None) -> None:
+    print(fmt.format(msg, **_styles.get()), file=file, flush=True)
 
 
 def _showwarning(
@@ -66,7 +67,27 @@ def _showwarning(
     _cprint('{yellow}WARNING{reset} {}', str(message))
 
 
-def _setup_cli() -> None:
+_max_terminal_width = shutil.get_terminal_size().columns - 2
+
+
+_fill = partial(textwrap.fill, subsequent_indent='  ', width=_max_terminal_width)
+
+
+def _log(message: str, *, origin: tuple[str, ...] | None = None) -> None:
+    if origin is None:
+        (first, *rest) = message.splitlines()
+        _cprint('{bold}{}{reset}', _fill(first, initial_indent='* '))
+        for line in rest:
+            print(_fill(line, initial_indent='  '))
+
+    elif origin[0] == 'subprocess':
+        initial_indent = '> ' if origin[1] == 'cmd' else '< '
+        file = sys.stderr if origin[1] == 'stderr' else None
+        for line in message.splitlines():
+            _cprint('{dim}{}{reset}', _fill(line, initial_indent=initial_indent), file=file)
+
+
+def _setup_cli(*, verbosity: int) -> None:
     warnings.showwarning = _showwarning
 
     if platform.system() == 'Windows':
@@ -77,6 +98,11 @@ def _setup_cli() -> None:
         except ModuleNotFoundError:
             pass
 
+    _init_colors()
+
+    _ctx.LOGGER.set(_log)
+    _ctx.VERBOSITY.set(verbosity)
+
 
 def _error(msg: str, code: int = 1) -> NoReturn:  # pragma: no cover
     """
@@ -89,18 +115,6 @@ def _error(msg: str, code: int = 1) -> NoReturn:  # pragma: no cover
     raise SystemExit(code)
 
 
-class _ProjectBuilder(ProjectBuilder):
-    @staticmethod
-    def log(message: str) -> None:
-        _cprint('{bold}* {}{reset}', message)
-
-
-class _DefaultIsolatedEnv(DefaultIsolatedEnv):
-    @staticmethod
-    def log(message: str) -> None:
-        _cprint('{bold}* {}{reset}', message)
-
-
 def _format_dep_chain(dep_chain: Sequence[str]) -> str:
     return ' -> '.join(dep.partition(';')[0].strip() for dep in dep_chain)
 
@@ -111,8 +125,8 @@ def _build_in_isolated_env(
     distribution: Distribution,
     config_settings: ConfigSettings | None,
 ) -> str:
-    with _DefaultIsolatedEnv() as env:
-        builder = _ProjectBuilder.from_isolated_env(env, srcdir)
+    with DefaultIsolatedEnv() as env:
+        builder = ProjectBuilder.from_isolated_env(env, srcdir)
         # first install the build dependencies
         env.install(builder.build_system_requires)
         # then get the extra required dependencies from the backend (which was installed in the call above :P)
@@ -127,7 +141,7 @@ def _build_in_current_env(
     config_settings: ConfigSettings | None,
     skip_dependency_check: bool = False,
 ) -> str:
-    builder = _ProjectBuilder(srcdir)
+    builder = ProjectBuilder(srcdir)
 
     if not skip_dependency_check:
         missing = builder.check_dependencies(distribution, config_settings or {})
@@ -176,6 +190,10 @@ def _handle_build_error() -> Iterator[None]:
             tb = traceback.format_exc(-1)
         _cprint('\n{dim}{}{reset}\n', tb.strip('\n'))
         _error(str(e))
+    except Exception as e:  # pragma: no cover
+        tb = traceback.format_exc().strip('\n')
+        _cprint('\n{dim}{}{reset}\n', tb)
+        _error(str(e))
 
 
 def _natural_language_list(elements: Sequence[str]) -> str:
@@ -250,7 +268,7 @@ def build_package_via_sdist(
         with tarfile.TarFile.open(sdist) as t:
             t.extractall(sdist_out)
             try:
-                _ProjectBuilder.log(f'Building {_natural_language_list(distributions)} from sdist')
+                _ctx.log(f'Building {_natural_language_list(distributions)} from sdist')
                 srcdir = os.path.join(sdist_out, sdist_name[: -len('.tar.gz')])
                 for distribution in distributions:
                     out = _build(isolation, srcdir, outdir, distribution, config_settings, skip_dependency_check)
@@ -283,12 +301,9 @@ def main_parser() -> argparse.ArgumentParser:
             ).strip(),
             '    ',
         ),
-        formatter_class=partial(
-            argparse.RawDescriptionHelpFormatter,
-            # Prevent argparse from taking up the entire width of the terminal window
-            # which impedes readability.
-            width=min(shutil.get_terminal_size().columns - 2, 127),
-        ),
+        # Prevent argparse from taking up the entire width of the terminal window
+        # which impedes readability.
+        formatter_class=partial(argparse.RawDescriptionHelpFormatter, width=min(_max_terminal_width, 127)),
     )
     parser.add_argument(
         'srcdir',
@@ -303,6 +318,14 @@ def main_parser() -> argparse.ArgumentParser:
         action='version',
         version=f"build {build.__version__} ({','.join(build.__path__)})",
     )
+    parser.add_argument(
+        '--verbose',
+        '-v',
+        dest='verbosity',
+        action='count',
+        default=0,
+        help='increase verbosity',
+    )
     parser.add_argument(
         '--sdist',
         '-s',
@@ -354,12 +377,13 @@ def main(cli_args: Sequence[str], prog: str | None = None) -> None:
     :param cli_args: CLI arguments
     :param prog: Program name to show in help text
     """
-    _setup_cli()
     parser = main_parser()
     if prog:
         parser.prog = prog
     args = parser.parse_args(cli_args)
 
+    _setup_cli(verbosity=args.verbosity)
+
     distributions: list[Distribution] = []
     config_settings = {}
 
@@ -387,19 +411,15 @@ def main(cli_args: Sequence[str], prog: str | None = None) -> None:
     else:
         build_call = build_package_via_sdist
         distributions = ['wheel']
-    try:
-        with _handle_build_error():
-            built = build_call(
-                args.srcdir, outdir, distributions, config_settings, not args.no_isolation, args.skip_dependency_check
-            )
-            artifact_list = _natural_language_list(
-                ['{underline}{}{reset}{bold}{green}'.format(artifact, **_STYLES) for artifact in built]
-            )
-            _cprint('{bold}{green}Successfully built {}{reset}', artifact_list)
-    except Exception as e:  # pragma: no cover
-        tb = traceback.format_exc().strip('\n')
-        _cprint('\n{dim}{}{reset}\n', tb)
-        _error(str(e))
+
+    with _handle_build_error():
+        built = build_call(
+            args.srcdir, outdir, distributions, config_settings, not args.no_isolation, args.skip_dependency_check
+        )
+        artifact_list = _natural_language_list(
+            ['{underline}{}{reset}{bold}{green}'.format(artifact, **_styles.get()) for artifact in built]
+        )
+        _cprint('{bold}{green}Successfully built {}{reset}', artifact_list)
 
 
 def entrypoint() -> None:

src/build/_builder.py

@@ -4,7 +4,6 @@
 
 import contextlib
 import difflib
-import logging
 import os
 import subprocess
 import sys
@@ -16,7 +15,7 @@
 
 import pyproject_hooks
 
-from . import env
+from . import _ctx, env
 from ._compat import tomllib
 from ._exceptions import (
     BuildBackendException,
@@ -37,9 +36,6 @@
 }
 
 
-_logger = logging.getLogger(__name__)
-
-
 def _find_typo(dictionary: Mapping[str, str], expected: str) -> None:
     for obj in dictionary:
         if difflib.SequenceMatcher(None, expected, obj).ratio() >= 0.8:
@@ -216,7 +212,7 @@ def get_requires_for_build(self, distribution: Distribution, config_settings: Co
             (``sdist`` or ``wheel``)
         :param config_settings: Config settings for the build backend
         """
-        self.log(f'Getting build dependencies for {distribution}...')
+        _ctx.log(f'Getting build dependencies for {distribution}...')
         hook_name = f'get_requires_for_build_{distribution}'
         get_requires = getattr(self._hook, hook_name)
 
@@ -252,7 +248,7 @@ def prepare(
         :param config_settings: Config settings for the build backend
         :returns: The full path to the prepared metadata directory
         """
-        self.log(f'Getting metadata for {distribution}...')
+        _ctx.log(f'Getting metadata for {distribution}...')
         try:
             return self._call_backend(
                 f'prepare_metadata_for_build_{distribution}',
@@ -282,7 +278,7 @@ def build(
             previous ``prepare`` call on the same ``distribution`` kind
         :returns: The full path to the built distribution
         """
-        self.log(f'Building {distribution}...')
+        _ctx.log(f'Building {distribution}...')
         kwargs = {} if metadata_directory is None else {'metadata_directory': metadata_directory}
         return self._call_backend(f'build_{distribution}', output_directory, config_settings, **kwargs)
 
@@ -349,15 +345,3 @@ def _handle_backend(self, hook: str) -> Iterator[None]:
             raise BuildBackendException(exception, f'Backend subprocess exited when trying to invoke {hook}') from None
         except Exception as exception:
             raise BuildBackendException(exception, exc_info=sys.exc_info()) from None
-
-    @staticmethod
-    def log(message: str) -> None:
-        """
-        Log a message.
-
-        The default implementation uses the logging module but this function can be
-        overridden by users to have a different implementation.
-
-        :param message: Message to output
-        """
-        _logger.log(logging.INFO, message, stacklevel=2)