Struct LogGuard 

pub struct LogGuard { /* private fields */ }

A guard that manages the lifecycle of the logging subsystem.

LogGuard ensures the logging thread remains active while instances exist and properly terminates when all guards are dropped. The system uses reference counting to track active guards - when the last LogGuard is dropped, the logging thread is joined to ensure all pending log messages are written before the process terminates.

Reference Counting

The logging system maintains a global atomic counter of active LogGuard instances. This ensures that:

• The logging thread remains active as long as at least one LogGuard exists.
• All log messages are properly flushed when intermediate guards are dropped.
• The logging thread is cleanly terminated and joined when the last guard is dropped.

Shutdown Behavior

When the last guard is dropped, the logging thread is signaled to close, drains pending messages, and is joined to ensure all logs are written before process termination.

Python on Windows: Non-deterministic GC order during interpreter shutdown can occasionally prevent proper thread join, resulting in truncated logs.

Limits

The system supports a maximum of 255 concurrent LogGuard instances.

Implementations

impl LogGuard

pub fn new() -> Option<Self>

Creates a new LogGuard instance from the global logger.

Returns None if logging has not been initialized or the active LogGuard count would exceed 255.

Trait Implementations

impl Debug for LogGuard

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl DerefToPyAny for LogGuard

impl Drop for LogGuard

fn drop(&mut self)

Handles cleanup when a LogGuard is dropped.

Sends Flush if other guards remain active, otherwise sends Close, joins the logging thread, and resets the subsystem state.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl ExtractPyClassWithClone for LogGuard

impl<'py> IntoPyObject<'py> for LogGuard

type Target = LogGuard

The Python output type

type Output = Bound<'py, <LogGuard as IntoPyObject<'py>>::Target>

The smart pointer type to use.

type Error = PyErr

The type returned in the event of a conversion error.

fn into_pyobject( self, py: Python<'py>, ) -> Result<<Self as IntoPyObject<'_>>::Output, <Self as IntoPyObject<'_>>::Error>

Performs the conversion.

impl PyClass for LogGuard

const NAME: &str = "LogGuard"

Name of the class.

type Frozen = False

Whether the pyclass is frozen.

impl PyClassImpl for LogGuard

const MODULE: Option<&str>

Module which the class will be associated with.

const IS_BASETYPE: bool = false

#[pyclass(subclass)]

const IS_SUBCLASS: bool = false

#[pyclass(extends=…)]

const IS_MAPPING: bool = false

#[pyclass(mapping)]

const IS_SEQUENCE: bool = false

#[pyclass(sequence)]

const IS_IMMUTABLE_TYPE: bool = false

#[pyclass(immutable_type)]

const RAW_DOC: &'static CStr = /// A guard that manages the lifecycle of the logging subsystem. /// /// `LogGuard` ensures the logging thread remains active while instances exist and properly /// terminates when all guards are dropped. The system uses reference counting to track active /// guards - when the last `LogGuard` is dropped, the logging thread is joined to ensure all /// pending log messages are written before the process terminates. /// /// # Reference Counting /// /// The logging system maintains a global atomic counter of active `LogGuard` instances. This /// ensures that: /// - The logging thread remains active as long as at least one `LogGuard` exists. /// - All log messages are properly flushed when intermediate guards are dropped. /// - The logging thread is cleanly terminated and joined when the last guard is dropped. /// /// # Shutdown Behavior /// /// When the last guard is dropped, the logging thread is signaled to close, drains pending /// messages, and is joined to ensure all logs are written before process termination. /// /// **Python on Windows:** Non-deterministic GC order during interpreter shutdown can /// occasionally prevent proper thread join, resulting in truncated logs. /// /// # Limits /// /// The system supports a maximum of 255 concurrent `LogGuard` instances.

Docstring for the class provided on the struct or enum.

const DOC: &'static CStr

Fully rendered class doc, including the text_signature if a constructor is defined.

type Layout = <<LogGuard as PyClassImpl>::BaseNativeType as PyClassBaseType>::Layout<LogGuard>

Description of how this class is laid out in memory

type BaseType = PyAny

Base class

type ThreadChecker = NoopThreadChecker

This handles following two situations:

type Inventory = Pyo3MethodsInventoryForLogGuard

type PyClassMutability = <<PyAny as PyClassBaseType>::PyClassMutability as PyClassMutability>::MutableChild

Immutable or mutable

type Dict = PyClassDummySlot

Specify this class has #[pyclass(dict)] or not.

type WeakRef = PyClassDummySlot

Specify this class has #[pyclass(weakref)] or not.

type BaseNativeType = PyAny

The closest native ancestor. This is PyAny by default, and when you declare #[pyclass(extends=PyDict)], it’s PyDict.

fn items_iter() -> PyClassItemsIter

fn lazy_type_object() -> &'static LazyTypeObject<Self>

fn dict_offset() -> Option<PyObjectOffset>

Used to provide the dictoffset slot (equivalent to tp_dictoffset)

fn weaklist_offset() -> Option<PyObjectOffset>

Used to provide the weaklistoffset slot (equivalent to tp_weaklistoffset

impl PyStubType for LogGuard

fn type_output() -> TypeInfo

The type to be used in the output signature, i.e. return type of the Python function or methods.

fn type_input() -> TypeInfo

The type to be used in the input signature, i.e. the arguments of the Python function or methods.

impl PyTypeInfo for LogGuard

const NAME: &str = <Self as ::pyo3::PyClass>::NAME

👎Deprecated since 0.28.0:

prefer using ::type_object(py).name() to get the correct runtime value

Class name.

const MODULE: Option<&str> = <Self as ::pyo3::impl_::pyclass::PyClassImpl>::MODULE

👎Deprecated since 0.28.0:

prefer using ::type_object(py).module() to get the correct runtime value

Module name, if any.

fn type_object_raw(py: Python<'_>) -> *mut PyTypeObject

Returns the PyTypeObject instance for this type.

fn type_object(py: Python<'_>) -> Bound<'_, PyType>

Returns the safe abstraction over the type object.

fn is_type_of(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type or a subclass of this type.

fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool

Checks if object is an instance of this type.