# Copyright (c) The OpenTracing Authors.
#
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# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
from __future__ import absolute_import
import asyncio
from opentracing import Scope
from opentracing.scope_managers import ThreadLocalScopeManager
from .constants import ACTIVE_ATTR
class AsyncioScopeManager(ThreadLocalScopeManager):
"""
:class:`~opentracing.ScopeManager` implementation for **asyncio**
that stores the :class:`~opentracing.Scope` in the current
:class:`Task` (:meth:`Task.current_task()`), falling back to
thread-local storage if none was being executed.
Automatic :class:`~opentracing.Span` propagation from
parent coroutines to their children is not provided, which needs to be
done manually:
.. code-block:: python
async def child_coroutine(span):
# activate the parent Span, but do not finish it upon
# deactivation. That will be done by the parent coroutine.
with tracer.scope_manager.activate(span, finish_on_close=False):
with tracer.start_active_span('child') as scope:
...
async def parent_coroutine():
with tracer.start_active_span('parent') as scope:
...
await child_coroutine(span)
...
"""
def activate(self, span, finish_on_close):
"""
Make a :class:`~opentracing.Span` instance active.
:param span: the :class:`~opentracing.Span` that should become active.
:param finish_on_close: whether *span* should automatically be
finished when :meth:`Scope.close()` is called.
If no :class:`Task` is being executed, thread-local
storage will be used to store the :class:`~opentracing.Scope`.
:return: a :class:`~opentracing.Scope` instance to control the end
of the active period for the :class:`~opentracing.Span`.
It is a programming error to neglect to call :meth:`Scope.close()`
on the returned instance.
"""
task = self._get_task()
if not task:
return super(AsyncioScopeManager, self).activate(span,
finish_on_close)
scope = _AsyncioScope(self, span, finish_on_close)
self._set_task_scope(scope, task)
return scope
@property
def active(self):
"""
Return the currently active :class:`~opentracing.Scope` which
can be used to access the currently active
:attr:`Scope.span`.
:return: the :class:`~opentracing.Scope` that is active,
or ``None`` if not available.
"""
task = self._get_task()
if not task:
return super(AsyncioScopeManager, self).active
return self._get_task_scope(task)
def _get_task(self):
try:
# Prevent failure when run from a thread
# without an event loop.
loop = asyncio.get_event_loop()
except RuntimeError:
return None
return asyncio.Task.current_task(loop=loop)
def _set_task_scope(self, scope, task=None):
if task is None:
task = self._get_task()
setattr(task, ACTIVE_ATTR, scope)
def _get_task_scope(self, task=None):
if task is None:
task = self._get_task()
return getattr(task, ACTIVE_ATTR, None)
class _AsyncioScope(Scope):
def __init__(self, manager, span, finish_on_close):
super(_AsyncioScope, self).__init__(manager, span)
self._finish_on_close = finish_on_close
self._to_restore = manager.active
def close(self):
if self.manager.active is not self:
return
self.manager._set_task_scope(self._to_restore)
if self._finish_on_close:
self.span.finish()
