def setup_logging()

in lib64/python3.6/dist-packages/pip/_internal/utils/logging.py [0:0]
78 lines of code
10 McCabe index (conditional complexity)

def setup_logging(verbosity, no_color, user_log_file):
    """Configures and sets up all of the logging
    """

    # Determine the level to be logging at.
    if verbosity >= 1:
        level = "DEBUG"
    elif verbosity == -1:
        level = "WARNING"
    elif verbosity == -2:
        level = "ERROR"
    elif verbosity <= -3:
        level = "CRITICAL"
    else:
        level = "INFO"

    # The "root" logger should match the "console" level *unless* we also need
    # to log to a user log file.
    include_user_log = user_log_file is not None
    if include_user_log:
        additional_log_file = user_log_file
        root_level = "DEBUG"
    else:
        additional_log_file = "/dev/null"
        root_level = level

    # Disable any logging besides WARNING unless we have DEBUG level logging
    # enabled for vendored libraries.
    vendored_log_level = "WARNING" if level in ["INFO", "ERROR"] else "DEBUG"

    # Shorthands for clarity
    log_streams = {
        "stdout": "ext://sys.stdout",
        "stderr": "ext://sys.stderr",
    }
    handler_classes = {
        "stream": "pip._internal.utils.logging.ColorizedStreamHandler",
        "file": "pip._internal.utils.logging.BetterRotatingFileHandler",
    }

    logging.config.dictConfig({
        "version": 1,
        "disable_existing_loggers": False,
        "filters": {
            "exclude_warnings": {
                "()": "pip._internal.utils.logging.MaxLevelFilter",
                "level": logging.WARNING,
            },
        },
        "formatters": {
            "indent": {
                "()": IndentingFormatter,
                "format": "%(message)s",
            },
        },
        "handlers": {
            "console": {
                "level": level,
                "class": handler_classes["stream"],
                "no_color": no_color,
                "stream": log_streams["stdout"],
                "filters": ["exclude_warnings"],
                "formatter": "indent",
            },
            "console_errors": {
                "level": "WARNING",
                "class": handler_classes["stream"],
                "no_color": no_color,
                "stream": log_streams["stderr"],
                "formatter": "indent",
            },
            "user_log": {
                "level": "DEBUG",
                "class": handler_classes["file"],
                "filename": additional_log_file,
                "delay": True,
                "formatter": "indent",
            },
        },
        "root": {
            "level": root_level,
            "handlers": ["console", "console_errors"] + (
                ["user_log"] if include_user_log else []
            ),
        },
        "loggers": {
            "pip._vendor": {
                "level": vendored_log_level
            }
        },
    })