tornado::stack_context Namespace Reference

Classes
class	_State
class	ExceptionStackContext
class	NullContext
class	StackContext
class	StackContextInconsistentError
Functions
def	_handle_exception
def	_remove_deactivated
def	run_with_stack_context
def	wrap
Variables
tuple	_state = _State()

---

Function Documentation

def tornado.stack_context._handle_exception	(		tail,
			exc
	)		[private]

Definition at line 352 of file stack_context.py.

def tornado.stack_context._remove_deactivated

(

contexts

)

[private]

Remove deactivated handlers from the chain

Definition at line 227 of file stack_context.py.

def tornado.stack_context.run_with_stack_context	(		context,
			func
	)

Run a coroutine ``func`` in the given `StackContext`.

It is not safe to have a ``yield`` statement within a ``with StackContext``
block, so it is difficult to use stack context with `.gen.coroutine`.
This helper function runs the function in the correct context while
keeping the ``yield`` and ``with`` statements syntactically separate.

Example::

    @gen.coroutine
    def incorrect():
        with StackContext(ctx):
            # ERROR: this will raise StackContextInconsistentError
            yield other_coroutine()

    @gen.coroutine
    def correct():
        yield run_with_stack_context(StackContext(ctx), other_coroutine)

.. versionadded:: 3.1

Definition at line 365 of file stack_context.py.

def tornado.stack_context.wrap

(

fn

)

Returns a callable object that will restore the current `StackContext`
when executed.

Use this whenever saving a callback to be executed later in a
different execution context (either in a different thread or
asynchronously in the same thread).

Definition at line 253 of file stack_context.py.

---

Variable Documentation

tuple tornado::stack_context::_state = _State()

Definition at line 85 of file stack_context.py.