Coverage for python/lsst/utils/logging.py: 56%
Shortcuts on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
Shortcuts on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1# This file is part of utils.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# Use of this source code is governed by a 3-clause BSD-style
10# license that can be found in the LICENSE file.
12from __future__ import annotations
14__all__ = ("TRACE", "VERBOSE", "getLogger", "LsstLogAdapter", "trace_set_at")
16import logging
17from logging import LoggerAdapter
18from deprecated.sphinx import deprecated
19from contextlib import contextmanager
21from typing import (
22 Any,
23 Generator,
24 List,
25 Optional,
26 Union,
27)
29try:
30 import lsst.log.utils as logUtils
31except ImportError:
32 logUtils = None
34# log level for trace (verbose debug).
35TRACE = 5
36logging.addLevelName(TRACE, "TRACE")
38# Verbose logging is midway between INFO and DEBUG.
39VERBOSE = (logging.INFO + logging.DEBUG) // 2
40logging.addLevelName(VERBOSE, "VERBOSE")
43def trace_set_at(name: str, number: int) -> None:
44 """Adjusts logging level to display messages with the trace number being
45 less than or equal to the provided value.
47 Parameters
48 ----------
49 name : `str`
50 Name of the logger.
51 number : `int`
52 The trace number threshold for display.
54 Notes
55 -----
56 Loggers ``TRACE0.`` to ``TRACE5.`` are set. All loggers above
57 the specified threshold are set to ``INFO`` and those below the threshold
58 are set to ``DEBUG``. The expectation is that ``TRACE`` loggers only
59 issue ``DEBUG`` log messages.
61 Examples
62 --------
64 .. code-block:: python
66 lsst.utils.logging.trace_set_at("lsst.afw", 3)
68 This will set loggers ``TRACE0.lsst.afw`` to ``TRACE3.lsst.afw`` to
69 ``DEBUG`` and ``TRACE4.lsst.afw`` and ``TRACE5.lsst.afw`` to ``INFO``.
71 Notes
72 -----
73 If ``lsst.log`` is installed, this function will also call
74 `lsst.log.utils.traceSetAt` to ensure that non-Python loggers are
75 also configured correctly.
76 """
77 for i in range(6):
78 level = logging.INFO if i > number else logging.DEBUG
79 log_name = f"TRACE{i}.{name}" if name else f"TRACE{i}"
80 logging.getLogger(log_name).setLevel(level)
82 # if lsst log is available also set the trace loggers there.
83 if logUtils is not None:
84 logUtils.traceSetAt(name, number)
87class _F:
88 """
89 Format, supporting `str.format()` syntax.
91 Notes
92 -----
93 This follows the recommendation from
94 https://docs.python.org/3/howto/logging-cookbook.html#using-custom-message-objects
95 """
96 def __init__(self, fmt: str, /, *args: Any, **kwargs: Any):
97 self.fmt = fmt
98 self.args = args
99 self.kwargs = kwargs
101 def __str__(self) -> str:
102 return self.fmt.format(*self.args, **self.kwargs)
105class LsstLogAdapter(LoggerAdapter):
106 """A special logging adapter to provide log features for LSST code.
108 Expected to be instantiated initially by a call to `getLogger()`.
110 This class provides enhancements over `logging.Logger` that include:
112 * Methods for issuing trace and verbose level log messages.
113 * Provision of a context manager to temporarily change the log level.
114 * Attachment of logging level constants to the class to make it easier
115 for a Task writer to access a specific log level without having to
116 know the underlying logger class.
117 """
119 # Store logging constants in the class for convenience. This is not
120 # something supported by Python loggers but can simplify some
121 # logic if the logger is available.
122 CRITICAL = logging.CRITICAL
123 ERROR = logging.ERROR
124 DEBUG = logging.DEBUG
125 INFO = logging.INFO
126 WARNING = logging.WARNING
128 # Python supports these but prefers they are not used.
129 FATAL = logging.FATAL
130 WARN = logging.WARN
132 # These are specific to Tasks
133 TRACE = TRACE
134 VERBOSE = VERBOSE
136 @contextmanager
137 def temporary_log_level(self, level: Union[int, str]) -> Generator:
138 """A context manager that temporarily sets the level of this logger.
140 Parameters
141 ----------
142 level : `int`
143 The new temporary log level.
144 """
145 old = self.level
146 self.setLevel(level)
147 try:
148 yield
149 finally:
150 self.setLevel(old)
152 @property
153 def level(self) -> int:
154 """Current level of this logger (``int``)."""
155 return self.logger.level
157 def getChild(self, name: str) -> LsstLogAdapter:
158 """Get the named child logger.
160 Parameters
161 ----------
162 name : `str`
163 Name of the child relative to this logger.
165 Returns
166 -------
167 child : `LsstLogAdapter`
168 The child logger.
169 """
170 return getLogger(name=name, logger=self.logger)
172 @deprecated(reason="Use Python Logger compatible isEnabledFor Will be removed after v23.",
173 version="v23", category=FutureWarning)
174 def isDebugEnabled(self) -> bool:
175 return self.isEnabledFor(self.DEBUG)
177 @deprecated(reason="Use Python Logger compatible 'name' attribute. Will be removed after v23.",
178 version="v23", category=FutureWarning)
179 def getName(self) -> str:
180 return self.name
182 @deprecated(reason="Use Python Logger compatible .level property. Will be removed after v23.",
183 version="v23", category=FutureWarning)
184 def getLevel(self) -> int:
185 return self.logger.level
187 def fatal(self, msg: str, *args: Any, **kwargs: Any) -> None:
188 # Python does not provide this method in LoggerAdapter but does
189 # not formally deprecated it in favor of critical() either.
190 # Provide it without deprecation message for consistency with Python.
191 # stacklevel=5 accounts for the forwarding of LoggerAdapter.
192 self.critical(msg, *args, **kwargs, stacklevel=4)
194 def verbose(self, fmt: str, *args: Any, **kwargs: Any) -> None:
195 """Issue a VERBOSE level log message.
197 Arguments are as for `logging.info`.
198 ``VERBOSE`` is between ``DEBUG`` and ``INFO``.
199 """
200 # There is no other way to achieve this other than a special logger
201 # method.
202 # Stacklevel is passed in so that the correct line is reported
203 # in the log record and not this line. 3 is this method,
204 # 2 is the level from `self.log` and 1 is the log infrastructure
205 # itself.
206 self.log(VERBOSE, fmt, *args, stacklevel=3, **kwargs)
208 def trace(self, fmt: str, *args: Any) -> None:
209 """Issue a TRACE level log message.
211 Arguments are as for `logging.info`.
212 ``TRACE`` is lower than ``DEBUG``.
213 """
214 # There is no other way to achieve this other than a special logger
215 # method. For stacklevel discussion see `verbose()`.
216 self.log(TRACE, fmt, *args, stacklevel=3)
218 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
219 version="v23", category=FutureWarning)
220 def tracef(self, fmt: str, *args: Any, **kwargs: Any) -> None:
221 # Stacklevel is 4 to account for the deprecation wrapper
222 self.log(TRACE, _F(fmt, *args, **kwargs), stacklevel=4)
224 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
225 version="v23", category=FutureWarning)
226 def debugf(self, fmt: str, *args: Any, **kwargs: Any) -> None:
227 self.log(logging.DEBUG, _F(fmt, *args, **kwargs), stacklevel=4)
229 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
230 version="v23", category=FutureWarning)
231 def infof(self, fmt: str, *args: Any, **kwargs: Any) -> None:
232 self.log(logging.INFO, _F(fmt, *args, **kwargs), stacklevel=4)
234 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
235 version="v23", category=FutureWarning)
236 def warnf(self, fmt: str, *args: Any, **kwargs: Any) -> None:
237 self.log(logging.WARNING, _F(fmt, *args, **kwargs), stacklevel=4)
239 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
240 version="v23", category=FutureWarning)
241 def errorf(self, fmt: str, *args: Any, **kwargs: Any) -> None:
242 self.log(logging.ERROR, _F(fmt, *args, **kwargs), stacklevel=4)
244 @deprecated(reason="Use Python Logger compatible method. Will be removed after v23.",
245 version="v23", category=FutureWarning)
246 def fatalf(self, fmt: str, *args: Any, **kwargs: Any) -> None:
247 self.log(logging.CRITICAL, _F(fmt, *args, **kwargs), stacklevel=4)
249 def setLevel(self, level: Union[int, str]) -> None:
250 """Set the level for the logger, trapping lsst.log values.
252 Parameters
253 ----------
254 level : `int`
255 The level to use. If the level looks too big to be a Python
256 logging level it is assumed to be a lsst.log level.
257 """
258 if isinstance(level, int) and level > logging.CRITICAL:
259 self.logger.warning("Attempting to set level to %d -- looks like an lsst.log level so scaling it"
260 " accordingly.", level)
261 level //= 1000
263 self.logger.setLevel(level)
265 @property
266 def handlers(self) -> List[logging.Handler]:
267 """Log handlers associated with this logger."""
268 return self.logger.handlers
270 def addHandler(self, handler: logging.Handler) -> None:
271 """Add a handler to this logger.
273 The handler is forwarded to the underlying logger.
274 """
275 self.logger.addHandler(handler)
277 def removeHandler(self, handler: logging.Handler) -> None:
278 """Remove the given handler from the underlying logger."""
279 self.logger.removeHandler(handler)
282def getLogger(name: Optional[str] = None, logger: logging.Logger = None) -> LsstLogAdapter:
283 """Get a logger compatible with LSST usage.
285 Parameters
286 ----------
287 name : `str`, optional
288 Name of the logger. Root logger if `None`.
289 logger : `logging.Logger` or `LsstLogAdapter`
290 If given the logger is converted to the relevant logger class.
291 If ``name`` is given the logger is assumed to be a child of the
292 supplied logger.
294 Returns
295 -------
296 logger : `LsstLogAdapter`
297 The relevant logger.
299 Notes
300 -----
301 A `logging.LoggerAdapter` is used since it is easier to provide a more
302 uniform interface than when using `logging.setLoggerClass`. An adapter
303 can be wrapped around the root logger and the `~logging.setLoggerClass`
304 will return the logger first given that name even if the name was
305 used before the `Task` was created.
306 """
307 if not logger:
308 logger = logging.getLogger(name)
309 elif name:
310 logger = logger.getChild(name)
311 return LsstLogAdapter(logger, {})
314LsstLoggers = Union[logging.Logger, LsstLogAdapter]