Add file logger

news/218-add-logger

@@ -0,0 +1,20 @@
+### Enhancements
+
+* Add option to log `conda-standalone` and `conda` outputs into a log file
+  using the `--log-file` CLI option. (#218)
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

src/conda_constructor/cli.py

@@ -4,11 +4,7 @@
 from pathlib import Path
 from typing import TYPE_CHECKING
 
-from .extract import DEFAULT_NUM_PROCESSORS, ExtractType, _NumProcessorsAction, extract
-from .uninstall import uninstall
-
-if sys.platform == "win32":
-    from .windows.path import add_remove_path
+from .extract import DEFAULT_NUM_PROCESSORS, ExtractType, _NumProcessorsAction
 
 if TYPE_CHECKING:
     from argparse import ArgumentParser, Namespace
@@ -173,6 +169,8 @@ def execute(args: Namespace) -> None | int:
     action: Callable
     kwargs = {}
     if args.cmd == "extract":
+        from .extract import extract
+
         action = extract
         kwargs.update(
             {
@@ -181,6 +179,8 @@ def execute(args: Namespace) -> None | int:
             }
         )
     elif args.cmd == "uninstall":
+        from .uninstall import uninstall
+
         action = uninstall
         kwargs.update(
             {
@@ -191,6 +191,8 @@ def execute(args: Namespace) -> None | int:
         )
     elif args.cmd == "windows" and sys.platform == "win32":
         if args.windows_cmd == "path":
+            from .windows.path import add_remove_path
+
             action = add_remove_path
             kwargs.update(
                 {

src/conda_constructor/uninstall.py

@@ -1,3 +1,4 @@
+import logging
 import os
 import re
 import sys
@@ -22,6 +23,13 @@
 from menuinst.cli.cli import install as install_shortcut
 from ruamel.yaml import YAML
 
+logger = logging.getLogger()
+# On Windows, these warnings are expected because the uninstaller may still be
+# accessing files (like install.log) that conda cannot rename.
+if sys.platform == "win32":
+    conda_logger = logging.getLogger("conda.gateways.disk.delete")
+    conda_logger.addFilter(lambda record: "Could not remove or rename" not in record.getMessage())
+
 
 def _remove_file_directory(file: Path, raise_on_error: bool = False):
     """
@@ -37,11 +45,14 @@ def _remove_file_directory(file: Path, raise_on_error: bool = False):
         elif file.is_symlink() or file.is_file():
             file.unlink()
     except PermissionError as e:
+        message = (
+            f"Could not remove {file}. "
+            "You may need to re-run with elevated privileges or manually remove this file."
+        )
         if raise_on_error:
-            raise PermissionError(
-                f"Could not remove {file}. "
-                "You may need to re-run with elevated privileges or manually remove this file."
-            ) from e
+            raise PermissionError(message) from e
+        else:
+            logger.warning(message, exc_info=e)
 
 
 def _remove_config_file_and_parents(file: Path, raise_on_error: bool = False):
@@ -163,7 +174,14 @@ def _run_conda_init_reverse(for_user: bool, prefix: Path, prefixes: list[Path]):
     # That function will search for activation scripts in sys.prefix which do no exist
     # in the extraction directory of conda-standalone.
     run_plan(plan)
-    run_plan_elevated(plan)
+    try:
+        run_plan_elevated(plan)
+    except Exception as exc:
+        logger.error(
+            "Could not revert some shell profiles because they require elevated privileges. "
+            "Check the output for lines with `needs sudo` and edit those files manually.",
+            exc_info=exc,
+        )
     print_plan_results(plan)
     for initializer in plan:
         target_path = initializer["kwargs"]["target_path"]
@@ -202,7 +220,13 @@ def _remove_environments(prefix: Path, prefixes: list[Path]):
         # Unprotect frozen environments first
         frozen_file = env_prefix / PREFIX_FROZEN_FILE
         if frozen_file.is_file():
-            _remove_file_directory(frozen_file, raise_on_error=True)
+            try:
+                _remove_file_directory(frozen_file, raise_on_error=True)
+            except PermissionError as e:
+                raise PermissionError(
+                    f"Failed to unprotect '{env_prefix}'. Try to re-run the uninstallation with "
+                    f"elevated privileges or remove the file '{frozen_file}' manually.",
+                ) from e
 
         install_shortcut(env_prefix, root_prefix=str(menuinst_base_prefix), remove_shortcuts=[])
         # If conda_root_prefix is the same as prefix, conda remove will not be able
@@ -214,7 +238,11 @@ def _remove_environments(prefix: Path, prefixes: list[Path]):
         if default_activation_prefix == env_prefix:
             os.environ["CONDA_DEFAULT_ACTIVATION_ENV"] = sys.prefix
             reset_context()
-        conda_main("remove", "-y", "-p", str(env_prefix), "--all")
+
+        return_code = conda_main("remove", "-y", "-p", str(env_prefix), "--all")
+        if return_code != 0:
+            raise RuntimeError(f"Failed to remove environment '{env_prefix}'.")
+
         if conda_root_prefix and conda_root_prefix == env_prefix:
             os.environ["CONDA_ROOT_PREFIX"] = str(conda_root_prefix)
             reset_context()
@@ -224,7 +252,9 @@ def _remove_environments(prefix: Path, prefixes: list[Path]):
 
 
 def _remove_caches():
-    conda_main("clean", "--all", "-y")
+    return_code = conda_main("clean", "--all", "-y")
+    if return_code != 0:
+        logger.warning("Failed to remove all cache files.")
     # Delete empty package cache directories
     for directory in context.pkgs_dirs:
         pkgs_dir = Path(directory)

src/entry_point.py

@@ -7,11 +7,28 @@
 preliminary work and handling some special cases that arise when PyInstaller is involved.
 """
 
+import argparse
+import logging
 import os
 import sys
+from contextlib import contextmanager, nullcontext
 from multiprocessing import freeze_support
 from pathlib import Path
 
+
+class StreamToLogger:
+    def __init__(self, logger, log_level=logging.INFO):
+        self.logger = logger
+        self.log_level = log_level
+
+    def write(self, buf):
+        self.logger.log(self.log_level, buf.rstrip())
+
+    def flush(self):
+        # Stream handlers need a flush method, but the log command flushes the buffer already
+        pass
+
+
 if os.name == "nt" and "SSLKEYLOGFILE" in os.environ:
     # This causes a crash with requests 2.32+ on Windows
     # Root cause is 'urllib3.util.ssl_.create_urllib3_context()'
@@ -114,6 +131,39 @@ def _patch_for_conda_run():
         os.environ.setdefault("CONDA_EXE", sys.executable)
 
 
+@contextmanager
+def setup_logger(logfile: Path):
+    """Forward all stdout and stderr output into a file logger.
+
+    This automatically captures all logger output.
+    """
+    plain_formatter = logging.Formatter("%(message)s")
+    plain_logfile_handler = logging.FileHandler(logfile)
+    plain_logfile_handler.setFormatter(plain_formatter)
+
+    stdout_logger = logging.getLogger("stdout_logger")
+    stdout_logger.setLevel(logging.INFO)
+    stdout_logger.propagate = False
+    stdout_console_handler = logging.StreamHandler(sys.__stdout__)
+    stdout_console_handler.setFormatter(plain_formatter)
+    stdout_logger.addHandler(stdout_console_handler)
+    stdout_logger.addHandler(plain_logfile_handler)
+
+    stderr_logger = logging.getLogger("stderr_logger")
+    stderr_logger.setLevel(logging.INFO)
+    stderr_logger.propagate = False
+    stderr_console_handler = logging.StreamHandler(sys.__stderr__)
+    stderr_console_handler.setFormatter(plain_formatter)
+    stderr_logger.addHandler(stderr_console_handler)
+    stderr_logger.addHandler(plain_logfile_handler)
+
+    sys.stdout = StreamToLogger(stdout_logger)
+    sys.stderr = StreamToLogger(stderr_logger)
+    yield
+    sys.stdout = sys.__stdout__
+    sys.stderr = sys.__stderr__
+
+
 def _conda_main():
     from conda.cli import main
 
@@ -132,7 +182,17 @@ def _conda_main():
     manager = get_plugin_manager()
     manager.load_plugins(plugin)
 
-    return main()
+    logger_parser = argparse.ArgumentParser(add_help=False)
+    logger_parser.add_argument("--log-file", type=Path)
+    args, remaining = logger_parser.parse_known_args()
+    if args.log_file:
+        sys.argv[1:] = remaining
+        logger_context = setup_logger(args.log_file.resolve())
+    else:
+        logger_context = nullcontext()
+
+    with logger_context:
+        return main()
 
 
 def _patch_constructor_args(argv: list[str] = sys.argv) -> list[str]:
@@ -146,9 +206,7 @@ def _patch_constructor_args(argv: list[str] = sys.argv) -> list[str]:
     if len(used_legacy_args) == 0:
         return argv
     elif len(used_legacy_args) > 1:
-        from argparse import ArgumentError
-
-        raise ArgumentError(
+        raise argparse.ArgumentError(
             None, f"The following arguments are mutually exclusive: {', '.join(used_legacy_args)}."
         )
     legacy_arg = used_legacy_args.pop()

tests/test_main.py

@@ -252,8 +252,10 @@ def test_conda_run():
         assert not process.stderr
 
 
-def test_conda_run_conda_exe():
+@pytest.mark.parametrize("with_log", (True, False), ids=("with log", "no log"))
+def test_conda_run_conda_exe(tmp_path: Path, with_log: bool):
     env = os.environ.copy()
+    log_file = tmp_path / "conda_run.log"
     for key in os.environ:
         if key.startswith(("CONDA", "_CONDA_", "__CONDA", "_CE_")):
             env.pop(key, None)
@@ -265,9 +267,18 @@ def test_conda_run_conda_exe():
         "python",
         "-c",
         "import sys,os;print(os.environ['CONDA_EXE'])",
+        *(("--log-file", str(log_file)) if with_log else ()),
         check=True,
         text=True,
         capture_output=True,
         env=env,
     )
     assert os.path.realpath(process.stdout.strip()) == os.path.realpath(CONDA_EXE)
+    if with_log:
+        assert log_file.exists()
+        log_text = log_file.read_text().strip()
+        if sys.platform.startswith("win") and os.environ.get("CI"):
+            # on CI, setup-miniconda registers `test` as auto-activate for every CMD
+            # which adds some unnecessary stderr output; so, only read the first line
+            log_text = log_text.split("\n")[0]
+        assert os.path.realpath(log_text.strip()) == os.path.realpath(CONDA_EXE)