# 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.
"""
The OpenTelemetry logging API describes the classes used to generate logs and events.
The :class:`.LoggerProvider` provides users access to the :class:`.Logger` which in
turn is used to create :class:`.Event` and :class:`.Log` objects.
This module provides abstract (i.e. unimplemented) classes required for
logging, and a concrete no-op implementation :class:`.NoOpLogger` that allows applications
to use the API package alone without a supporting implementation.
To get a logger, you need to provide the package name from which you are
calling the logging APIs to OpenTelemetry by calling `LoggerProvider.get_logger`
with the calling module name and the version of your package.
The following code shows how to obtain a logger using the global :class:`.LoggerProvider`::
from opentelemetry._logs import get_logger
logger = get_logger("example-logger")
.. versionadded:: 1.15.0
"""
from abc import ABC, abstractmethod
from logging import getLogger
from os import environ
from typing import Any, Optional, cast
from opentelemetry._logs.severity import SeverityNumber
from opentelemetry.environment_variables import _OTEL_PYTHON_LOGGER_PROVIDER
from opentelemetry.trace.span import TraceFlags
from opentelemetry.util._once import Once
from opentelemetry.util._providers import _load_provider
from opentelemetry.util.types import Attributes
_logger = getLogger(__name__)
[docs]class LogRecord(ABC):
"""A LogRecord instance represents an event being logged.
LogRecord instances are created and emitted via `Logger`
every time something is logged. They contain all the information
pertinent to the event being logged.
"""
def __init__(
self,
timestamp: Optional[int] = None,
observed_timestamp: Optional[int] = None,
trace_id: Optional[int] = None,
span_id: Optional[int] = None,
trace_flags: Optional["TraceFlags"] = None,
severity_text: Optional[str] = None,
severity_number: Optional[SeverityNumber] = None,
body: Optional[Any] = None,
attributes: Optional["Attributes"] = None,
):
self.timestamp = timestamp
self.observed_timestamp = observed_timestamp
self.trace_id = trace_id
self.span_id = span_id
self.trace_flags = trace_flags
self.severity_text = severity_text
self.severity_number = severity_number
self.body = body # type: ignore
self.attributes = attributes
[docs]class Logger(ABC):
"""Handles emitting events and logs via `LogRecord`."""
def __init__(
self,
name: str,
version: Optional[str] = None,
schema_url: Optional[str] = None,
) -> None:
super().__init__()
self._name = name
self._version = version
self._schema_url = schema_url
[docs] @abstractmethod
def emit(self, record: "LogRecord") -> None:
"""Emits a :class:`LogRecord` representing a log to the processing pipeline."""
[docs]class NoOpLogger(Logger):
"""The default Logger used when no Logger implementation is available.
All operations are no-op.
"""
[docs] def emit(self, record: "LogRecord") -> None:
pass
[docs]class LoggerProvider(ABC):
"""
LoggerProvider is the entry point of the API. It provides access to Logger instances.
"""
[docs] @abstractmethod
def get_logger(
self,
name: str,
version: Optional[str] = None,
schema_url: Optional[str] = None,
) -> Logger:
"""Returns a `Logger` for use by the given instrumentation library.
For any two calls it is undefined whether the same or different
`Logger` instances are returned, even for different library names.
This function may return different `Logger` types (e.g. a no-op logger
vs. a functional logger).
Args:
name: The name of the instrumenting module.
``__name__`` may not be used as this can result in
different logger names if the loggers are in different files.
It is better to use a fixed string that can be imported where
needed and used consistently as the name of the logger.
This should *not* be the name of the module that is
instrumented but the name of the module doing the instrumentation.
E.g., instead of ``"requests"``, use
``"opentelemetry.instrumentation.requests"``.
version: Optional. The version string of the
instrumenting library. Usually this should be the same as
``pkg_resources.get_distribution(instrumenting_library_name).version``.
schema_url: Optional. Specifies the Schema URL of the emitted telemetry.
"""
[docs]class NoOpLoggerProvider(LoggerProvider):
"""The default LoggerProvider used when no LoggerProvider implementation is available."""
[docs] def get_logger(
self,
name: str,
version: Optional[str] = None,
schema_url: Optional[str] = None,
) -> Logger:
"""Returns a NoOpLogger."""
super().get_logger(name, version=version, schema_url=schema_url)
return NoOpLogger(name, version=version, schema_url=schema_url)
# TODO: ProxyLoggerProvider
_LOGGER_PROVIDER_SET_ONCE = Once()
_LOGGER_PROVIDER = None
[docs]def get_logger_provider() -> LoggerProvider:
"""Gets the current global :class:`~.LoggerProvider` object."""
global _LOGGER_PROVIDER # pylint: disable=global-statement
if _LOGGER_PROVIDER is None:
if _OTEL_PYTHON_LOGGER_PROVIDER not in environ.keys():
# TODO: return proxy
_LOGGER_PROVIDER = NoOpLoggerProvider()
return _LOGGER_PROVIDER
logger_provider: LoggerProvider = _load_provider( # type: ignore
_OTEL_PYTHON_LOGGER_PROVIDER, "logger_provider"
)
_set_logger_provider(logger_provider, log=False)
# _LOGGER_PROVIDER will have been set by one thread
return cast("LoggerProvider", _LOGGER_PROVIDER)
def _set_logger_provider(logger_provider: LoggerProvider, log: bool) -> None:
def set_lp() -> None:
global _LOGGER_PROVIDER # pylint: disable=global-statement
_LOGGER_PROVIDER = logger_provider # type: ignore
did_set = _LOGGER_PROVIDER_SET_ONCE.do_once(set_lp)
if log and not did_set:
_logger.warning("Overriding of current LoggerProvider is not allowed")
[docs]def set_logger_provider(meter_provider: LoggerProvider) -> None:
"""Sets the current global :class:`~.LoggerProvider` object.
This can only be done once, a warning will be logged if any further attempt
is made.
"""
_set_logger_provider(meter_provider, log=True)
[docs]def get_logger(
instrumenting_module_name: str,
instrumenting_library_version: str = "",
logger_provider: Optional[LoggerProvider] = None,
) -> "Logger":
"""Returns a `Logger` for use within a python process.
This function is a convenience wrapper for
opentelemetry.sdk._logs.LoggerProvider.get_logger.
If logger_provider param is omitted the current configured one is used.
"""
if logger_provider is None:
logger_provider = get_logger_provider()
return logger_provider.get_logger(
instrumenting_module_name, instrumenting_library_version
)