Source code for structlog.threadlocal

# 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.

Primitives to keep context global but thread (and greenlet) local.

from __future__ import absolute_import, division, print_function

import contextlib
import threading
import uuid

from structlog._config import BoundLoggerLazyProxy

    from greenlet import getcurrent
except ImportError:
    from threading import local as ThreadLocal
    from weakref import WeakKeyDictionary

    class ThreadLocal(object):
        threading.local() replacement for greenlets.

        def __init__(self):
            self.__dict__["_weakdict"] = WeakKeyDictionary()

        def __getattr__(self, name):
            key = getcurrent()
                return self._weakdict[key][name]
            except KeyError:
                raise AttributeError(name)

        def __setattr__(self, name, val):
            key = getcurrent()
            self._weakdict.setdefault(key, {})[name] = val

        def __delattr__(self, name):
            key = getcurrent()
                del self._weakdict[key][name]
            except KeyError:
                raise AttributeError(name)

[docs]def wrap_dict(dict_class): """ Wrap a dict-like class and return the resulting class. The wrapped class and used to keep global in the current thread. :param type dict_class: Class used for keeping context. :rtype: `type` """ Wrapped = type( "WrappedDict-" + str(uuid.uuid4()), (_ThreadLocalDictWrapper,), {} ) Wrapped._tl = ThreadLocal() Wrapped._dict_class = dict_class return Wrapped
[docs]def as_immutable(logger): """ Extract the context from a thread local logger into an immutable logger. :param structlog.BoundLogger logger: A logger with *possibly* thread local state. :rtype: :class:`~structlog.BoundLogger` with an immutable context. """ if isinstance(logger, BoundLoggerLazyProxy): logger = logger.bind() try: ctx = logger._context._tl.dict_.__class__(logger._context._dict) bl = logger.__class__( logger._logger, processors=logger._processors, context={} ) bl._context = ctx return bl except AttributeError: return logger
[docs]@contextlib.contextmanager def tmp_bind(logger, **tmp_values): """ Bind *tmp_values* to *logger* & memorize current state. Rewind afterwards. """ saved = as_immutable(logger)._context try: yield logger.bind(**tmp_values) finally: logger._context.clear() logger._context.update(saved)
class _ThreadLocalDictWrapper(object): """ Wrap a dict-like class and keep the state *global* but *thread-local*. Attempts to re-initialize only updates the wrapped dictionary. Useful for short-lived threaded applications like requests in web app. Use :func:`wrap` to instantiate and use :func:`` to clear the context. """ def __init__(self, *args, **kw): """ We cheat. A context dict gets never recreated. """ if args and isinstance(args[0], self.__class__): # our state is global, no need to look at args[0] if it's of our # class self._dict.update(**kw) else: self._dict.update(*args, **kw) @property def _dict(self): """ Return or create and return the current context. """ try: return self.__class__._tl.dict_ except AttributeError: self.__class__._tl.dict_ = self.__class__._dict_class() return self.__class__._tl.dict_ def __repr__(self): return "<{0}({1!r})>".format(self.__class__.__name__, self._dict) def __eq__(self, other): # Same class == same dictionary return self.__class__ == other.__class__ def __ne__(self, other): return not self.__eq__(other) # Proxy methods necessary for structlog. # Dunder methods don't trigger __getattr__ so we need to proxy by hand. def __iter__(self): return self._dict.__iter__() def __setitem__(self, key, value): self._dict[key] = value def __delitem__(self, key): self._dict.__delitem__(key) def __len__(self): return self._dict.__len__() def __getattr__(self, name): method = getattr(self._dict, name) return method _CONTEXT = threading.local()
[docs]def merge_threadlocal_context(logger, method_name, event_dict): """ A processor that merges in a global (thread-local) context. Use this as your first processor in :func:`structlog.configure` to ensure thread-local context is included in all log calls. """ context = _get_context().copy() context.update(event_dict) return context
[docs]def clear_threadlocal(): """ Clear the thread-local context. The typical use-case for this function is to invoke it early in request-handling code. """ _CONTEXT.context = {}
[docs]def bind_threadlocal(**kwargs): """ Put keys and values into the thread-local context. Use this instead of :func:`~structlog.BoundLogger.bind` when you want some context to be global (thread-local). """ _get_context().update(kwargs)
def _get_context(): try: return _CONTEXT.context except AttributeError: _CONTEXT.context = {} return _CONTEXT.context