# 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.
"""
Processors useful regardless of the logging framework.
"""
from __future__ import absolute_import, division, print_function
import datetime
import json
import operator
import sys
import time
import six
from structlog._frames import (
_find_first_app_frame_and_name,
_format_exception,
_format_stack,
)
[docs]class KeyValueRenderer(object):
"""
Render `event_dict` as a list of ``Key=repr(Value)`` pairs.
:param bool sort_keys: Whether to sort keys when formatting.
:param list key_order: List of keys that should be rendered in this exact
order. Missing keys will be rendered as ``None``, extra keys depending
on *sort_keys* and the dict class.
:param bool drop_missing: When ``True``, extra keys in *key_order* will be
dropped rather than rendered as ``None``.
:param bool repr_native_str: When ``True``, :func:`repr()` is also applied
to native strings (i.e. unicode on Python 3 and bytes on Python 2).
Setting this to ``False`` is useful if you want to have human-readable
non-ASCII output on Python 2.
.. versionadded:: 0.2.0 *key_order*
.. versionadded:: 16.1.0 *drop_missing*
.. versionadded:: 17.1.0 *repr_native_str*
"""
def __init__(self, sort_keys=False, key_order=None, drop_missing=False,
repr_native_str=True):
# Use an optimized version for each case.
if key_order and sort_keys:
def ordered_items(event_dict):
items = []
for key in key_order:
value = event_dict.pop(key, None)
if value is not None or not drop_missing:
items.append((key, value))
items += sorted(event_dict.items())
return items
elif key_order:
def ordered_items(event_dict):
items = []
for key in key_order:
value = event_dict.pop(key, None)
if value is not None or not drop_missing:
items.append((key, value))
items += event_dict.items()
return items
elif sort_keys:
def ordered_items(event_dict):
return sorted(event_dict.items())
else:
ordered_items = operator.methodcaller('items')
self._ordered_items = ordered_items
if repr_native_str is True:
self._repr = repr
else:
def _repr(inst):
if isinstance(inst, str):
return inst
else:
return repr(inst)
self._repr = _repr
def __call__(self, _, __, event_dict):
return ' '.join(k + '=' + self._repr(v)
for k, v in self._ordered_items(event_dict))
[docs]class UnicodeEncoder(object):
"""
Encode unicode values in `event_dict`.
:param str encoding: Encoding to encode to (default: ``'utf-8'``).
:param str errors: How to cope with encoding errors (default
``'backslashreplace'``).
Useful if you're running Python 2 as otherwise ``u"abc"`` will be rendered
as ``'u"abc"'``.
Just put it in the processor chain before the renderer.
"""
def __init__(self, encoding='utf-8', errors='backslashreplace'):
self._encoding = encoding
self._errors = errors
def __call__(self, logger, name, event_dict):
for key, value in event_dict.items():
if isinstance(value, six.text_type):
event_dict[key] = value.encode(self._encoding, self._errors)
return event_dict
[docs]class UnicodeDecoder(object):
"""
Decode byte string values in `event_dict`.
:param str encoding: Encoding to decode from (default: ``'utf-8'``).
:param str errors: How to cope with encoding errors (default:
``'replace'``).
Useful if you're running Python 3 as otherwise ``b"abc"`` will be rendered
as ``'b"abc"'``.
Just put it in the processor chain before the renderer.
.. versionadded:: 15.4.0
"""
def __init__(self, encoding='utf-8', errors='replace'):
self._encoding = encoding
self._errors = errors
def __call__(self, logger, name, event_dict):
for key, value in event_dict.items():
if isinstance(value, bytes):
event_dict[key] = value.decode(self._encoding, self._errors)
return event_dict
[docs]class JSONRenderer(object):
"""
Render the `event_dict` using ``serializer(event_dict, **json_kw)``.
:param dict json_kw: Are passed unmodified to *serializer*.
:param callable serializer: A :func:`json.dumps`-compatible callable that
will be used to format the string. This can be used to use alternative
JSON encoders like `simplejson
<https://pypi.python.org/pypi/simplejson/>`_ or `RapidJSON
<https://pypi.python.org/pypi/python-rapidjson/>`_ (faster but Python
3-only) (default: :func:`json.dumps`).
.. versionadded:: 0.2.0
Support for ``__structlog__`` serialization method.
.. versionadded:: 15.4.0
``serializer`` parameter.
"""
def __init__(self, serializer=json.dumps, **dumps_kw):
self._dumps_kw = dumps_kw
self._dumps = serializer
def __call__(self, logger, name, event_dict):
return self._dumps(event_dict, default=_json_fallback_handler,
**self._dumps_kw)
def _json_fallback_handler(obj):
"""
Serialize custom datatypes and pass the rest to __structlog__ & repr().
"""
# circular imports :(
from structlog.threadlocal import _ThreadLocalDictWrapper
if isinstance(obj, _ThreadLocalDictWrapper):
return obj._dict
else:
try:
return obj.__structlog__()
except AttributeError:
return repr(obj)
[docs]class TimeStamper(object):
"""
Add a timestamp to `event_dict`.
.. note::
You should let OS tools take care of timestamping. See also
:doc:`logging-best-practices`.
:param str fmt: strftime format string, or ``"iso"`` for `ISO 8601
<https://en.wikipedia.org/wiki/ISO_8601>`_, or `None` for a `UNIX
timestamp <https://en.wikipedia.org/wiki/Unix_time>`_.
:param bool utc: Whether timestamp should be in UTC or local time.
:param str key: Target key in `event_dict` for added timestamps.
"""
def __new__(cls, fmt=None, utc=True, key='timestamp'):
if fmt is None and not utc:
raise ValueError('UNIX timestamps are always UTC.')
now_method = getattr(datetime.datetime, 'utcnow' if utc else 'now')
if fmt is None:
def stamper(self, _, __, event_dict):
event_dict[key] = time.time()
return event_dict
elif fmt.upper() == 'ISO':
if utc:
def stamper(self, _, __, event_dict):
event_dict[key] = now_method().isoformat() + 'Z'
return event_dict
else:
def stamper(self, _, __, event_dict):
event_dict[key] = now_method().isoformat()
return event_dict
else:
def stamper(self, _, __, event_dict):
event_dict[key] = now_method().strftime(fmt)
return event_dict
return type('TimeStamper', (object,), {'__call__': stamper})()
def _figure_out_exc_info(v):
"""
Depending on the Python version will try to do the smartest thing possible
to transform *v* into an ``exc_info`` tuple.
:rtype: tuple
"""
if six.PY3 and isinstance(v, BaseException):
return (v.__class__, v, getattr(v, "__traceback__"))
elif isinstance(v, tuple):
return v
elif v:
return sys.exc_info()
return v
[docs]class ExceptionPrettyPrinter(object):
"""
Pretty print exceptions and remove them from the `event_dict`.
:param file file: Target file for output (default: ``sys.stdout``).
This processor is mostly for development and testing so you can read
exceptions properly formatted.
It behaves like :func:`format_exc_info` except it removes the exception
data from the event dictionary after printing it.
It's tolerant to having `format_exc_info` in front of itself in the
processor chain but doesn't require it. In other words, it handles both
`exception` as well as `exc_info` keys.
.. versionadded:: 0.4.0
.. versionchanged:: 16.0.0
Added support for passing exceptions as ``exc_info`` on Python 3.
"""
def __init__(self, file=None):
if file is not None:
self._file = file
else:
self._file = sys.stdout
def __call__(self, logger, name, event_dict):
exc = event_dict.pop("exception", None)
if exc is None:
exc_info = _figure_out_exc_info(event_dict.pop("exc_info", None))
if exc_info:
exc = _format_exception(exc_info)
if exc:
print(exc, file=self._file)
return event_dict
[docs]class StackInfoRenderer(object):
"""
Add stack information with key `stack` if `stack_info` is true.
Useful when you want to attach a stack dump to a log entry without
involving an exception.
It works analogously to the `stack_info` argument of the Python 3 standard
library logging but works on both 2 and 3.
.. versionadded:: 0.4.0
"""
def __call__(self, logger, name, event_dict):
if event_dict.pop('stack_info', None):
event_dict['stack'] = _format_stack(
_find_first_app_frame_and_name()[0]
)
return event_dict