# Copyright The OpenTelemetry Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Global Error Handler
This module provides a global error handler and an interface that allows
error handlers to be registered with the global error handler via entry points.
A default error handler is also provided.
To use this feature, users can create an error handler that is registered
using the ``opentelemetry_error_handler`` entry point. A class is to be
registered in this entry point, this class must inherit from the
``opentelemetry.sdk.error_handler.ErrorHandler`` class and implement the
corresponding ``handle`` method. This method will receive the exception object
that is to be handled. The error handler class should also inherit from the
exception classes it wants to handle. For example, this would be an error
handler that handles ``ZeroDivisionError``:
.. code:: python
from opentelemetry.sdk.error_handler import ErrorHandler
from logging import getLogger
logger = getLogger(__name__)
class ErrorHandler0(ErrorHandler, ZeroDivisionError):
def _handle(self, error: Exception, *args, **kwargs):
logger.exception("ErrorHandler0 handling a ZeroDivisionError")
To use the global error handler, just instantiate it as a context manager where
you want exceptions to be handled:
.. code:: python
from opentelemetry.sdk.error_handler import GlobalErrorHandler
with GlobalErrorHandler():
1 / 0
If the class of the exception raised in the scope of the ``GlobalErrorHandler``
object is not parent of any registered error handler, then the default error
handler will handle the exception. This default error handler will only log the
exception to standard logging, the exception won't be raised any further.
"""
from abc import ABC, abstractmethod
from logging import getLogger
from opentelemetry.util._importlib_metadata import entry_points
logger = getLogger(__name__)
[docs]class ErrorHandler(ABC):
@abstractmethod
def _handle(self, error: Exception, *args, **kwargs):
"""
Handle an exception
"""
class _DefaultErrorHandler(ErrorHandler):
"""
Default error handler
This error handler just logs the exception using standard logging.
"""
# pylint: disable=useless-return
def _handle(self, error: Exception, *args, **kwargs):
logger.exception("Error handled by default error handler: ")
return None
[docs]class GlobalErrorHandler:
"""
Global error handler
This is a singleton class that can be instantiated anywhere to get the
global error handler. This object provides a handle method that receives
an exception object that will be handled by the registered error handlers.
"""
_instance = None
def __new__(cls) -> "GlobalErrorHandler":
if cls._instance is None:
cls._instance = super().__new__(cls)
return cls._instance
def __enter__(self):
pass
# pylint: disable=no-self-use
def __exit__(self, exc_type, exc_value, traceback):
if exc_value is None:
return None
plugin_handled = False
error_handler_entry_points = entry_points(
group="opentelemetry_error_handler"
)
for error_handler_entry_point in error_handler_entry_points:
error_handler_class = error_handler_entry_point.load()
if issubclass(error_handler_class, exc_value.__class__):
try:
error_handler_class()._handle(exc_value)
plugin_handled = True
# pylint: disable=broad-except
except Exception as error_handling_error:
logger.exception(
"%s error while handling error"
" %s by error handler %s",
error_handling_error.__class__.__name__,
exc_value.__class__.__name__,
error_handler_class.__name__,
)
if not plugin_handled:
_DefaultErrorHandler()._handle(exc_value)
return True