Reference for ultralytics/utils/__init__.py

def plt_settings(rcparams=None, backend="Agg"):
    """Decorator to temporarily set rc parameters and the backend for a plotting function.

    Args:
        rcparams (dict, optional): Dictionary of rc parameters to set.
        backend (str, optional): Name of the backend to use.

    Returns:
        (Callable): Decorated function with temporarily set rc parameters and backend.

    Examples:
        >>> @plt_settings({"font.size": 12})
        >>> def plot_function():
        ...     plt.figure()
        ...     plt.plot([1, 2, 3])
        ...     plt.show()

        >>> with plt_settings({"font.size": 12}):
        ...     plt.figure()
        ...     plt.plot([1, 2, 3])
        ...     plt.show()
    """
    if rcparams is None:
        rcparams = {"font.size": 11}

    def decorator(func):
        """Decorator to apply temporary rc parameters and backend to a function."""

        def wrapper(*args, **kwargs):
            """Set rc parameters and backend, call the original function, and restore the settings."""
            import matplotlib.pyplot as plt  # scope for faster 'import ultralytics'

            original_backend = plt.get_backend()
            switch = backend.lower() != original_backend.lower()
            if switch:
                plt.close("all")  # auto-close()ing of figures upon backend switching is deprecated since 3.8
                plt.switch_backend(backend)

            # Plot with backend and always revert to original backend
            try:
                with plt.rc_context(rcparams):
                    result = func(*args, **kwargs)
            finally:
                if switch:
                    plt.close("all")
                    plt.switch_backend(original_backend)
            return result

        return wrapper

    return decorator

def set_logging(name="LOGGING_NAME", verbose=True):
    """Set up logging with UTF-8 encoding and configurable verbosity.

    This function configures logging for the Ultralytics library, setting the appropriate logging level and formatter
    based on the verbosity flag and the current process rank. It handles special cases for Windows environments where
    UTF-8 encoding might not be the default.

    Args:
        name (str): Name of the logger.
        verbose (bool): Flag to set logging level to INFO if True, ERROR otherwise.

    Returns:
        (logging.Logger): Configured logger object.

    Examples:
        >>> set_logging(name="ultralytics", verbose=True)
        >>> logger = logging.getLogger("ultralytics")
        >>> logger.info("This is an info message")

    Notes:
        - On Windows, this function attempts to reconfigure stdout to use UTF-8 encoding if possible.
        - If reconfiguration is not possible, it falls back to a custom formatter that handles non-UTF-8 environments.
        - The function sets up a StreamHandler with the appropriate formatter and level.
        - The logger's propagate flag is set to False to prevent duplicate logging in parent loggers.
    """
    level = logging.INFO if verbose and RANK in {-1, 0} else logging.ERROR  # rank in world for Multi-GPU trainings

    class PrefixFormatter(logging.Formatter):
        def format(self, record):
            """Format log records with prefixes based on level."""
            # Apply prefixes based on log level
            if record.levelno == logging.WARNING:
                prefix = "WARNING" if WINDOWS else "WARNING ⚠️"
                record.msg = f"{prefix} {record.msg}"
            elif record.levelno == logging.ERROR:
                prefix = "ERROR" if WINDOWS else "ERROR ❌"
                record.msg = f"{prefix} {record.msg}"

            # Handle emojis in message based on platform
            formatted_message = super().format(record)
            return emojis(formatted_message)

    formatter = PrefixFormatter("%(message)s")

    # Handle Windows UTF-8 encoding issues
    if WINDOWS and hasattr(sys.stdout, "encoding") and sys.stdout.encoding != "utf-8":
        with contextlib.suppress(Exception):
            # Attempt to reconfigure stdout to use UTF-8 encoding if possible
            if hasattr(sys.stdout, "reconfigure"):
                sys.stdout.reconfigure(encoding="utf-8")
            # For environments where reconfigure is not available, wrap stdout in a TextIOWrapper
            elif hasattr(sys.stdout, "buffer"):
                import io

                sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding="utf-8")

    # Create and configure the StreamHandler with the appropriate formatter and level
    stream_handler = logging.StreamHandler(sys.stdout)
    stream_handler.setFormatter(formatter)
    stream_handler.setLevel(level)

    # Set up the logger
    logger = logging.getLogger(name)
    logger.setLevel(level)
    logger.addHandler(stream_handler)
    logger.propagate = False
    return logger

def emojis(string=""):
    """Return platform-dependent emoji-safe version of string."""
    return string.encode().decode("ascii", "ignore") if WINDOWS else string

def read_device_model() -> str:
    """Read the device model information from the system and cache it for quick access.

    Returns:
        (str): Kernel release information.
    """
    return platform.release().lower()

def is_ubuntu() -> bool:
    """Check if the OS is Ubuntu.

    Returns:
        (bool): True if OS is Ubuntu, False otherwise.
    """
    try:
        with open("/etc/os-release") as f:
            return "ID=ubuntu" in f.read()
    except FileNotFoundError:
        return False

def is_colab():
    """Check if the current script is running inside a Google Colab notebook.

    Returns:
        (bool): True if running inside a Colab notebook, False otherwise.
    """
    return "COLAB_RELEASE_TAG" in os.environ or "COLAB_BACKEND_VERSION" in os.environ

def is_kaggle():
    """Check if the current script is running inside a Kaggle kernel.

    Returns:
        (bool): True if running inside a Kaggle kernel, False otherwise.
    """
    return os.environ.get("PWD") == "/kaggle/working" and os.environ.get("KAGGLE_URL_BASE") == "https://www.kaggle.com"

def is_jupyter():
    """Check if the current script is running inside a Jupyter Notebook.

    Returns:
        (bool): True if running inside a Jupyter Notebook, False otherwise.

    Notes:
        - Only works on Colab and Kaggle, other environments like Jupyterlab and Paperspace are not reliably detectable.
        - "get_ipython" in globals() method suffers false positives when IPython package installed manually.
    """
    return IS_COLAB or IS_KAGGLE

def is_runpod():
    """Check if the current script is running inside a RunPod container.

    Returns:
        (bool): True if running in RunPod, False otherwise.
    """
    return "RUNPOD_POD_ID" in os.environ

def is_docker() -> bool:
    """Determine if the script is running inside a Docker container.

    Returns:
        (bool): True if the script is running inside a Docker container, False otherwise.
    """
    try:
        return os.path.exists("/.dockerenv")
    except Exception:
        return False

def is_raspberrypi() -> bool:
    """Determine if the Python environment is running on a Raspberry Pi.

    Returns:
        (bool): True if running on a Raspberry Pi, False otherwise.
    """
    return "rpi" in DEVICE_MODEL

@lru_cache(maxsize=3)
def is_jetson(jetpack=None) -> bool:
    """Determine if the Python environment is running on an NVIDIA Jetson device.

    Args:
        jetpack (int | None): If specified, check for specific JetPack version (4, 5, 6).

    Returns:
        (bool): True if running on an NVIDIA Jetson device, False otherwise.
    """
    if jetson := ("tegra" in DEVICE_MODEL):
        if jetpack:
            try:
                content = open("/etc/nv_tegra_release").read()
                version_map = {4: "R32", 5: "R35", 6: "R36"}  # JetPack to L4T major version mapping
                return jetpack in version_map and version_map[jetpack] in content
            except Exception:
                return False
    return jetson

def is_online() -> bool:
    """Fast online check using DNS (v4/v6) resolution (Cloudflare + Google).

    Returns:
        (bool): True if connection is successful, False otherwise.
    """
    if str(os.getenv("YOLO_OFFLINE", "")).lower() == "true":
        return False

    for host in ("one.one.one.one", "dns.google"):
        try:
            socket.getaddrinfo(host, 0, socket.AF_UNSPEC, 0, 0, socket.AI_ADDRCONFIG)
            return True
        except OSError:
            continue
    return False

def is_pip_package(filepath: str = __name__) -> bool:
    """Determine if the file at the given filepath is part of a pip package.

    Args:
        filepath (str): The filepath to check.

    Returns:
        (bool): True if the file is part of a pip package, False otherwise.
    """
    import importlib.util

    # Get the spec for the module
    spec = importlib.util.find_spec(filepath)

    # Return whether the spec is not None and the origin is not None (indicating it is a package)
    return spec is not None and spec.origin is not None

def is_dir_writeable(dir_path: str | Path) -> bool:
    """Check if a directory is writable.

    Args:
        dir_path (str | Path): The path to the directory.

    Returns:
        (bool): True if the directory is writable, False otherwise.
    """
    return os.access(str(dir_path), os.W_OK)

def is_pytest_running():
    """Determine whether pytest is currently running or not.

    Returns:
        (bool): True if pytest is running, False otherwise.
    """
    return ("PYTEST_CURRENT_TEST" in os.environ) or ("pytest" in sys.modules) or ("pytest" in Path(ARGV[0]).stem)

def is_github_action_running() -> bool:
    """Determine if the current environment is a GitHub Actions runner.

    Returns:
        (bool): True if the current environment is a GitHub Actions runner, False otherwise.
    """
    return "GITHUB_ACTIONS" in os.environ and "GITHUB_WORKFLOW" in os.environ and "RUNNER_OS" in os.environ

def get_default_args(func):
    """Return a dictionary of default arguments for a function.

    Args:
        func (callable): The function to inspect.

    Returns:
        (dict): A dictionary where each key is a parameter name, and each value is the default value of that parameter.
    """
    signature = inspect.signature(func)
    return {k: v.default for k, v in signature.parameters.items() if v.default is not inspect.Parameter.empty}

def get_ubuntu_version():
    """Retrieve the Ubuntu version if the OS is Ubuntu.

    Returns:
        (str): Ubuntu version or None if not an Ubuntu OS.
    """
    if is_ubuntu():
        try:
            with open("/etc/os-release") as f:
                return re.search(r'VERSION_ID="(\d+\.\d+)"', f.read())[1]
        except (FileNotFoundError, AttributeError):
            return None

def get_user_config_dir(sub_dir="Ultralytics"):
    """Return a writable config dir, preferring YOLO_CONFIG_DIR and being OS-aware.

    Args:
        sub_dir (str): The name of the subdirectory to create.

    Returns:
        (Path): The path to the user config directory.
    """
    if env_dir := os.getenv("YOLO_CONFIG_DIR"):
        p = Path(env_dir).expanduser() / sub_dir
    elif LINUX:
        p = Path(os.getenv("XDG_CONFIG_HOME", Path.home() / ".config")) / sub_dir
    elif WINDOWS:
        p = Path.home() / "AppData" / "Roaming" / sub_dir
    elif MACOS:
        p = Path.home() / "Library" / "Application Support" / sub_dir
    else:
        raise ValueError(f"Unsupported operating system: {platform.system()}")

    if p.exists():  # already created → trust it
        return p
    if is_dir_writeable(p.parent):  # create if possible
        p.mkdir(parents=True, exist_ok=True)
        return p

    # Fallbacks for Docker, GCP/AWS functions where only /tmp is writable
    for alt in [Path("/tmp") / sub_dir, Path.cwd() / sub_dir]:
        if alt.exists():
            return alt
        if is_dir_writeable(alt.parent):
            alt.mkdir(parents=True, exist_ok=True)
            LOGGER.warning(
                f"user config directory '{p}' is not writable, using '{alt}'. Set YOLO_CONFIG_DIR to override."
            )
            return alt

    # Last fallback → CWD
    p = Path.cwd() / sub_dir
    p.mkdir(parents=True, exist_ok=True)
    return p