1# Copyright The OpenTelemetry Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15from __future__ import annotations
16
17from contextvars import ContextVar, Token
18
19from opentelemetry.context.context import Context, _RuntimeContext
20
21
22class ContextVarsRuntimeContext(_RuntimeContext):
23 """An implementation of the RuntimeContext interface which wraps ContextVar under
24 the hood. This is the preferred implementation for usage with Python 3.5+
25 """
26
27 _CONTEXT_KEY = "current_context"
28
29 def __init__(self) -> None:
30 self._current_context = ContextVar(
31 self._CONTEXT_KEY, default=Context()
32 )
33
34 def attach(self, context: Context) -> Token[Context]:
35 """Sets the current `Context` object. Returns a
36 token that can be used to reset to the previous `Context`.
37
38 Args:
39 context: The Context to set.
40 """
41 return self._current_context.set(context)
42
43 def get_current(self) -> Context:
44 """Returns the current `Context` object."""
45 return self._current_context.get()
46
47 def detach(self, token: Token[Context]) -> None:
48 """Resets Context to a previous value
49
50 Args:
51 token: A reference to a previous Context.
52 """
53 self._current_context.reset(token)
54
55
56__all__ = ["ContextVarsRuntimeContext"]