215 lines
6.2 KiB
Python
215 lines
6.2 KiB
Python
# Copyright 2017 The Abseil Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Module to convert log levels between Abseil Python, C++, and Python standard.
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This converter has to convert (best effort) between three different
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logging level schemes:
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* **cpp**: The C++ logging level scheme used in Abseil C++.
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* **absl**: The absl.logging level scheme used in Abseil Python.
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* **standard**: The python standard library logging level scheme.
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Here is a handy ascii chart for easy mental mapping::
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LEVEL | cpp | absl | standard |
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---------+-----+--------+----------+
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DEBUG | 0 | 1 | 10 |
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INFO | 0 | 0 | 20 |
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WARNING | 1 | -1 | 30 |
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ERROR | 2 | -2 | 40 |
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CRITICAL | 3 | -3 | 50 |
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FATAL | 3 | -3 | 50 |
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Note: standard logging ``CRITICAL`` is mapped to absl/cpp ``FATAL``.
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However, only ``CRITICAL`` logs from the absl logger (or absl.logging.fatal)
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will terminate the program. ``CRITICAL`` logs from non-absl loggers are treated
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as error logs with a message prefix ``"CRITICAL - "``.
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Converting from standard to absl or cpp is a lossy conversion.
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Converting back to standard will lose granularity. For this reason,
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users should always try to convert to standard, the richest
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representation, before manipulating the levels, and then only to cpp
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or absl if those level schemes are absolutely necessary.
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"""
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import logging
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STANDARD_CRITICAL = logging.CRITICAL
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STANDARD_ERROR = logging.ERROR
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STANDARD_WARNING = logging.WARNING
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STANDARD_INFO = logging.INFO
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STANDARD_DEBUG = logging.DEBUG
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# These levels are also used to define the constants
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# FATAL, ERROR, WARNING, INFO, and DEBUG in the
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# absl.logging module.
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ABSL_FATAL = -3
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ABSL_ERROR = -2
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ABSL_WARNING = -1
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ABSL_WARN = -1 # Deprecated name.
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ABSL_INFO = 0
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ABSL_DEBUG = 1
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ABSL_LEVELS = {ABSL_FATAL: 'FATAL',
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ABSL_ERROR: 'ERROR',
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ABSL_WARNING: 'WARNING',
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ABSL_INFO: 'INFO',
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ABSL_DEBUG: 'DEBUG'}
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# Inverts the ABSL_LEVELS dictionary
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ABSL_NAMES = {'FATAL': ABSL_FATAL,
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'ERROR': ABSL_ERROR,
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'WARNING': ABSL_WARNING,
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'WARN': ABSL_WARNING, # Deprecated name.
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'INFO': ABSL_INFO,
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'DEBUG': ABSL_DEBUG}
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ABSL_TO_STANDARD = {ABSL_FATAL: STANDARD_CRITICAL,
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ABSL_ERROR: STANDARD_ERROR,
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ABSL_WARNING: STANDARD_WARNING,
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ABSL_INFO: STANDARD_INFO,
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ABSL_DEBUG: STANDARD_DEBUG}
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# Inverts the ABSL_TO_STANDARD
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STANDARD_TO_ABSL = {v: k for (k, v) in ABSL_TO_STANDARD.items()}
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def get_initial_for_level(level):
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"""Gets the initial that should start the log line for the given level.
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It returns:
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* ``'I'`` when: ``level < STANDARD_WARNING``.
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* ``'W'`` when: ``STANDARD_WARNING <= level < STANDARD_ERROR``.
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* ``'E'`` when: ``STANDARD_ERROR <= level < STANDARD_CRITICAL``.
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* ``'F'`` when: ``level >= STANDARD_CRITICAL``.
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Args:
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level: int, a Python standard logging level.
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Returns:
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The first initial as it would be logged by the C++ logging module.
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"""
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if level < STANDARD_WARNING:
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return 'I'
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elif level < STANDARD_ERROR:
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return 'W'
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elif level < STANDARD_CRITICAL:
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return 'E'
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else:
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return 'F'
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def absl_to_cpp(level):
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"""Converts an absl log level to a cpp log level.
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Args:
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level: int, an absl.logging level.
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Raises:
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TypeError: Raised when level is not an integer.
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Returns:
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The corresponding integer level for use in Abseil C++.
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"""
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if not isinstance(level, int):
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raise TypeError(f'Expect an int level, found {type(level)}')
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if level >= 0:
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# C++ log levels must be >= 0
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return 0
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else:
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return -level
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def absl_to_standard(level):
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"""Converts an integer level from the absl value to the standard value.
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Args:
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level: int, an absl.logging level.
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Raises:
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TypeError: Raised when level is not an integer.
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Returns:
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The corresponding integer level for use in standard logging.
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"""
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if not isinstance(level, int):
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raise TypeError(f'Expect an int level, found {type(level)}')
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if level < ABSL_FATAL:
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level = ABSL_FATAL
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if level <= ABSL_DEBUG:
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return ABSL_TO_STANDARD[level]
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# Maps to vlog levels.
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return STANDARD_DEBUG - level + 1
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def string_to_standard(level):
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"""Converts a string level to standard logging level value.
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Args:
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level: str, case-insensitive ``'debug'``, ``'info'``, ``'warning'``,
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``'error'``, ``'fatal'``.
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Returns:
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The corresponding integer level for use in standard logging.
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"""
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return absl_to_standard(ABSL_NAMES.get(level.upper()))
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def standard_to_absl(level):
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"""Converts an integer level from the standard value to the absl value.
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Args:
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level: int, a Python standard logging level.
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Raises:
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TypeError: Raised when level is not an integer.
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Returns:
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The corresponding integer level for use in absl logging.
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"""
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if not isinstance(level, int):
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raise TypeError(f'Expect an int level, found {type(level)}')
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if level < 0:
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level = 0
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if level < STANDARD_DEBUG:
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# Maps to vlog levels.
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return STANDARD_DEBUG - level + 1
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elif level < STANDARD_INFO:
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return ABSL_DEBUG
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elif level < STANDARD_WARNING:
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return ABSL_INFO
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elif level < STANDARD_ERROR:
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return ABSL_WARNING
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elif level < STANDARD_CRITICAL:
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return ABSL_ERROR
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else:
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return ABSL_FATAL
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def standard_to_cpp(level):
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"""Converts an integer level from the standard value to the cpp value.
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Args:
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level: int, a Python standard logging level.
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Raises:
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TypeError: Raised when level is not an integer.
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Returns:
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The corresponding integer level for use in cpp logging.
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"""
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return absl_to_cpp(standard_to_absl(level))
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