# SPDX-License-Identifier: MIT OR Apache-2.0
# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the MIT License. See the LICENSE file in the root of this
# repository for complete details.
"""
Logger classes responsible for output.
"""
from __future__ import annotations
import copy
import sys
import threading
from pickle import PicklingError
from sys import stderr, stdout
from typing import IO, Any, BinaryIO, TextIO
from structlog._utils import until_not_interrupted
WRITE_LOCKS: dict[IO[Any], threading.Lock] = {}
def _get_lock_for_file(file: IO[Any]) -> threading.Lock:
lock = WRITE_LOCKS.get(file)
if lock is None:
lock = threading.Lock()
WRITE_LOCKS[file] = lock
return lock
[docs]
class PrintLogger:
"""
Print events into a file.
Args:
file: File to print to. (default: `sys.stdout`)
>>> from structlog import PrintLogger
>>> PrintLogger().info("hello")
hello
Useful if you follow `current logging best practices
<logging-best-practices>`.
Also very useful for testing and examples since `logging` is finicky in
doctests.
.. versionchanged:: 22.1.0
The implementation has been switched to use `print` for better
monkeypatchability.
"""
def __init__(self, file: TextIO | None = None):
self._file = file or stdout
self._lock = _get_lock_for_file(self._file)
def __getstate__(self) -> str:
"""
Our __getattr__ magic makes this necessary.
"""
if self._file is stdout:
return "stdout"
if self._file is stderr:
return "stderr"
raise PicklingError(
"Only PrintLoggers to sys.stdout and sys.stderr can be pickled."
)
def __setstate__(self, state: Any) -> None:
"""
Our __getattr__ magic makes this necessary.
"""
if state == "stdout":
self._file = stdout
else:
self._file = stderr
self._lock = _get_lock_for_file(self._file)
def __deepcopy__(self, memodict: dict[str, object]) -> PrintLogger:
"""
Create a new PrintLogger with the same attributes. Similar to pickling.
"""
if self._file not in (stdout, stderr):
raise copy.error(
"Only PrintLoggers to sys.stdout and sys.stderr "
"can be deepcopied."
)
newself = self.__class__(self._file)
newself._lock = _get_lock_for_file(newself._file)
return newself
def __repr__(self) -> str:
return f"<PrintLogger(file={self._file!r})>"
[docs]
def msg(self, message: str) -> None:
"""
Print *message*.
"""
f = self._file if self._file is not stdout else None
with self._lock:
until_not_interrupted(print, message, file=f, flush=True)
log = debug = info = warn = warning = msg
fatal = failure = err = error = critical = exception = msg
[docs]
class PrintLoggerFactory:
r"""
Produce `PrintLogger`\ s.
To be used with `structlog.configure`\ 's ``logger_factory``.
Args:
file: File to print to. (default: `sys.stdout`)
Positional arguments are silently ignored.
.. versionadded:: 0.4.0
"""
def __init__(self, file: TextIO | None = None):
self._file = file
def __call__(self, *args: Any) -> PrintLogger:
return PrintLogger(self._file)
[docs]
class WriteLogger:
"""
Write events into a file.
Args:
file: File to print to. (default: `sys.stdout`)
>>> from structlog import WriteLogger
>>> WriteLogger().info("hello")
hello
Useful if you follow
`current logging best practices <logging-best-practices>`.
Also very useful for testing and examples since `logging` is finicky in
doctests.
A little faster and a little less versatile than `structlog.PrintLogger`.
.. versionadded:: 22.1.0
"""
def __init__(self, file: TextIO | None = None):
self._file = file or sys.stdout
self._write = self._file.write
self._flush = self._file.flush
self._lock = _get_lock_for_file(self._file)
def __getstate__(self) -> str:
"""
Our __getattr__ magic makes this necessary.
"""
if self._file is stdout:
return "stdout"
if self._file is stderr:
return "stderr"
raise PicklingError(
"Only WriteLoggers to sys.stdout and sys.stderr can be pickled."
)
def __setstate__(self, state: Any) -> None:
"""
Our __getattr__ magic makes this necessary.
"""
if state == "stdout":
self._file = stdout
else:
self._file = stderr
self._lock = _get_lock_for_file(self._file)
def __deepcopy__(self, memodict: dict[str, object]) -> WriteLogger:
"""
Create a new WriteLogger with the same attributes. Similar to pickling.
"""
if self._file not in (sys.stdout, sys.stderr):
raise copy.error(
"Only WriteLoggers to sys.stdout and sys.stderr "
"can be deepcopied."
)
newself = self.__class__(self._file)
newself._write = newself._file.write
newself._flush = newself._file.flush
newself._lock = _get_lock_for_file(newself._file)
return newself
def __repr__(self) -> str:
return f"<WriteLogger(file={self._file!r})>"
[docs]
def msg(self, message: str) -> None:
"""
Write and flush *message*.
"""
with self._lock:
until_not_interrupted(self._write, message + "\n")
until_not_interrupted(self._flush)
log = debug = info = warn = warning = msg
fatal = failure = err = error = critical = exception = msg
[docs]
class WriteLoggerFactory:
r"""
Produce `WriteLogger`\ s.
To be used with `structlog.configure`\ 's ``logger_factory``.
Args:
file: File to print to. (default: `sys.stdout`)
Positional arguments are silently ignored.
.. versionadded:: 22.1.0
"""
def __init__(self, file: TextIO | None = None):
self._file = file
def __call__(self, *args: Any) -> WriteLogger:
return WriteLogger(self._file)
[docs]
class BytesLogger:
r"""
Writes bytes into a file.
Args:
file: File to print to. (default: `sys.stdout`\ ``.buffer``)
Useful if you follow `current logging best practices
<logging-best-practices>` together with a formatter that returns bytes
(e.g. `orjson <https://github.com/ijl/orjson>`_).
.. versionadded:: 20.2.0
"""
__slots__ = ("_file", "_write", "_flush", "_lock")
def __init__(self, file: BinaryIO | None = None):
self._file = file or sys.stdout.buffer
self._write = self._file.write
self._flush = self._file.flush
self._lock = _get_lock_for_file(self._file)
def __getstate__(self) -> str:
"""
Our __getattr__ magic makes this necessary.
"""
if self._file is sys.stdout.buffer:
return "stdout"
if self._file is sys.stderr.buffer:
return "stderr"
raise PicklingError(
"Only BytesLoggers to sys.stdout and sys.stderr can be pickled."
)
def __setstate__(self, state: Any) -> None:
"""
Our __getattr__ magic makes this necessary.
"""
if state == "stdout":
self._file = sys.stdout.buffer
else:
self._file = sys.stderr.buffer
self._write = self._file.write
self._flush = self._file.flush
self._lock = _get_lock_for_file(self._file)
def __deepcopy__(self, memodict: dict[str, object]) -> BytesLogger:
"""
Create a new BytesLogger with the same attributes. Similar to pickling.
"""
if self._file not in (sys.stdout.buffer, sys.stderr.buffer):
raise copy.error(
"Only BytesLoggers to sys.stdout and sys.stderr "
"can be deepcopied."
)
newself = self.__class__(self._file)
newself._write = newself._file.write
newself._flush = newself._file.flush
newself._lock = _get_lock_for_file(newself._file)
return newself
def __repr__(self) -> str:
return f"<BytesLogger(file={self._file!r})>"
[docs]
def msg(self, message: bytes) -> None:
"""
Write *message*.
"""
with self._lock:
until_not_interrupted(self._write, message + b"\n")
until_not_interrupted(self._flush)
log = debug = info = warn = warning = msg
fatal = failure = err = error = critical = exception = msg
[docs]
class BytesLoggerFactory:
r"""
Produce `BytesLogger`\ s.
To be used with `structlog.configure`\ 's ``logger_factory``.
Args:
file: File to print to. (default: `sys.stdout`\ ``.buffer``)
Positional arguments are silently ignored.
.. versionadded:: 20.2.0
"""
__slots__ = ("_file",)
def __init__(self, file: BinaryIO | None = None):
self._file = file
def __call__(self, *args: Any) -> BytesLogger:
return BytesLogger(self._file)