twisted.python.log

module documentation

(source)

Logging and metrics infrastructure.

Interface	`ILogObserver`	An observer which can do something with log events.
Class	`DefaultObserver`	Default observer.
Class	`FileLogObserver`	Log observer that writes to a file-like object.
Class	`ILogContext`	Actually, this interface is just a synonym for the dictionary interface, but it serves as a key for the default information in a log.
Class	`Logger`	This represents a class which may 'own' a log. Used by subclassing.
Class	`LogPublisher`	Class for singleton log message publishing.
Class	`NullFile`	A file-like object that discards everything.
Class	`PythonLoggingObserver`	Output twisted messages to Python standard library `logging` module.
Class	`StdioOnnaStick`	Class that pretends to be stdout/err, and turns writes into log messages.
Function	`addObserver`	Add a log observer to the global publisher.
Function	`callWithContext`	Undocumented
Function	`callWithLogger`	Utility method which wraps a function in a try:/except:, logs a failure if one occurs, and uses the system's logPrefix.
Function	`discardLogs`	Discard messages logged via the global `logfile` object.
Function	`err`	Write a failure to the log.
Function	`msg`	Publish a message to the global log publisher.
Function	`removeObserver`	Remove a log observer from the global publisher.
Function	`showwarning`	Publish a Python warning through the global log publisher.
Function	`startLogging`	Initialize logging to a specified file.
Function	`startLoggingWithObserver`	Initialize logging to a specified observer. If setStdout is true (defaults to yes), also redirect sys.stdout and sys.stderr to the specified file.
Function	`textFromEventDict`	Extract text from an event dict passed to a log observer. If it cannot handle the dict, it returns None.
Variable	`defaultObserver`	Undocumented
Variable	`EventDict`	Undocumented
Variable	`logerr`	Undocumented
Variable	`logfile`	Undocumented
Variable	`theLogPublisher`	Undocumented
Class	`_GlobalStartStopObserver`	Mix-in for global log observers that can start and stop.
Function	`_actually`	A decorator that returns its argument rather than the thing it is decorating.
Function	`_safeFormat`	Try to format a string, swallowing all errors to always return a string.

@_actually(theLogPublisher.addObserver)
def addObserver(observer): (source)

Add a log observer to the global publisher.

Parameters
observer:`callable`	a log observer
See Also
`LogPublisher.addObserver`

def callWithContext(ctx, func, *args, **kw): (source)

Undocumented

def callWithLogger(logger, func, *args, **kw): (source)

Utility method which wraps a function in a try:/except:, logs a failure if one occurs, and uses the system's logPrefix.

def discardLogs(): (source)

Discard messages logged via the global logfile object.

def err(_stuff=None, _why=None, **kw): (source)

Write a failure to the log.

The _stuff and _why parameters use an underscore prefix to lessen the chance of colliding with a keyword argument the application wishes to pass. It is intended that they be supplied with arguments passed positionally, not by keyword.

Parameters
_stuff:`None`, `Exception`, or `Failure`.	The failure to log. If `_stuff` is `None` a new `Failure` will be created from the current exception state. If `_stuff` is an `Exception` instance it will be wrapped in a `Failure`.
_why:`str`	The source of this failure. This will be logged along with `_stuff` and should describe the context in which the failure occurred.
**kw	Undocumented

@_actually(theLogPublisher.msg)
def msg(*message, **event): (source)

Publish a message to the global log publisher.

Parameters
*message:`tuple` of `str` (native string)	the log message
**event:`dict` mapping `str` (native string) to `object`	fields for the log event
See Also
`LogPublisher.msg`

@_actually(theLogPublisher.removeObserver)
def removeObserver(observer): (source)

Remove a log observer from the global publisher.

Parameters
observer:`callable`	a log observer previously added with `addObserver`
See Also
`LogPublisher.removeObserver`

@_actually(theLogPublisher.showwarning)
def showwarning(): (source)

Publish a Python warning through the global log publisher.

See Also
`LogPublisher.showwarning`

def startLogging(file, *a, **kw): (source)

Initialize logging to a specified file.

Returns
A `FileLogObserver` if a new observer is added, None otherwise.

def startLoggingWithObserver(observer, setStdout=1): (source)

Initialize logging to a specified observer. If setStdout is true (defaults to yes), also redirect sys.stdout and sys.stderr to the specified file.

def textFromEventDict(eventDict): (source)

Extract text from an event dict passed to a log observer. If it cannot handle the dict, it returns None.

The possible keys of eventDict are:

message: by default, it holds the final text. It's required, but can be empty if either isError or format is provided (the first having the priority).
isError: boolean indicating the nature of the event.
failure: failure.Failure instance, required if the event is an error.
why: if defined, used as header of the traceback in case of errors.
format: string format used in place of message to customize the event. It uses all keys present in eventDict to format the text.

Other keys will be used when applying the format, or ignored.

Parameters
eventDict:`EventDict`	Undocumented
Returns
`Optional[str]`	Undocumented

defaultObserver = (source)

Undocumented

EventDict = (source)

Undocumented

logerr = (source)

Undocumented

logfile = (source)

Undocumented

theLogPublisher = (source)

Undocumented

def _actually(something): (source)

A decorator that returns its argument rather than the thing it is decorating.

This allows the documentation generator to see an alias for a method or constant as an object with a docstring and thereby document it and allow references to it statically.

Parameters
something:`object`	An object to create an alias for.
Returns
`object`	a 1-argument callable that returns `something`

def _safeFormat(fmtString, fmtDict): (source)

Try to format a string, swallowing all errors to always return a string.

Parameters
fmtString:`str`	a `%`-format string
fmtDict:`Dict[str, Any]`	string formatting arguments for `fmtString`
Returns
`str`	A native string, formatted from `fmtString` and `fmtDict`.
Note
For backward-compatibility reasons, this function ensures that it returns a native string, meaning `bytes` in Python 2 and `str` in Python 3.