twisted.logger.LogBeginner : API documentation

class documentation

class twisted.logger.LogBeginner: (source)

A LogBeginner holds state related to logging before logging has begun, and begins logging when told to do so. Logging "begins" when someone has selected a set of observers, like, for example, a FileLogObserver that writes to a file on disk, or to standard output.

Applications will not typically need to instantiate this class, except those which intend to initialize the global logging system themselves, which may wish to instantiate this for testing. The global instance for the current process is exposed as twisted.logger.globalLogBeginner.

Before logging has begun, a LogBeginner will:

Log any critical messages (e.g.: unhandled exceptions) to the given file-like object.
Save (a limited number of) log events in a LimitedHistoryLogObserver.

Method	__init__	Initialize this `LogBeginner`.
Method	beginLoggingTo	Begin logging to the given set of observers. This will:
Method	showwarning	Twisted-enabled wrapper around `warnings.showwarning`.
Class Variable	_DEFAULT_BUFFER_SIZE	The default size for the initial log events buffer.
Instance Variable	_initialBuffer	A buffer of messages logged before logging began.
Instance Variable	_publisher	The log publisher passed in to `LogBeginner`'s constructor.
Instance Variable	_log	The logger used to log messages about the operation of the `LogBeginner` itself.
Instance Variable	_stdio	An object with `stderr` and `stdout` attributes (like the `sys` module) which will be replaced when redirecting standard I/O.
Instance Variable	_temporaryObserver	If not `None`, an `ILogObserver` that observes events on `_publisher` for this `LogBeginner`.
Instance Variable	_warningsModule	Undocumented
Instance Variable	_previousBegin	Undocumented
Instance Variable	_oldshowwarning	Undocumented

_DEFAULT_BUFFER_SIZE = (source)

The default size for the initial log events buffer.

(type: int)

_initialBuffer = (source)

A buffer of messages logged before logging began.

_publisher = (source)

The log publisher passed in to LogBeginner's constructor.

_log = (source)

The logger used to log messages about the operation of the LogBeginner itself.

_stdio = (source)

An object with stderr and stdout attributes (like the sys module) which will be replaced when redirecting standard I/O.

_temporaryObserver = (source)

If not None, an ILogObserver that observes events on _publisher for this LogBeginner.

def __init__(self, publisher, errorStream, stdio, warningsModule, initialBufferSize=None): (source)

Initialize this LogBeginner.

Parameters	publisher	Undocumented (type: `LogPublisher`)
	errorStream	Undocumented (type: `IO[Any]`)
	stdio	Undocumented (type: `object`)
	warningsModule	Undocumented (type: `Any`)
	initialBufferSize	The size of the event buffer into which events are collected until `beginLoggingTo` is called. Or `None` to use the default size. (type: `Optional[int]`)

_warningsModule = (source)

Undocumented

_previousBegin = (source)

Undocumented

_oldshowwarning = (source)

Undocumented

def beginLoggingTo(self, observers, discardBuffer=False, redirectStandardIO=True): (source)

Begin logging to the given set of observers. This will:

Add all the observers given in observers to the LogPublisher associated with this LogBeginner.
Optionally re-direct standard output and standard error streams to the logging system.
Re-play any messages that were previously logged to that publisher to the new observers, if discardBuffer is not set.
Stop logging critical errors from the LogPublisher as strings to the errorStream associated with this LogBeginner, and allow them to be logged normally.
Re-direct warnings from the warnings module associated with this LogBeginner to log messages.

Parameters	observers	The observers to register. (type: `Iterable[ILogObserver]`)
	discardBuffer	Whether to discard the buffer and not re-play it to the added observers. (This argument is provided mainly for compatibility with legacy concerns.) (type: `bool`)
	redirectStandardIO	If true, redirect standard output and standard error to the observers. (type: `bool`)
Note	Since a `LogBeginner` is designed to encapsulate the transition between process-startup and log-system-configuration, this method is intended to be invoked once.

def showwarning(self, message, category, filename, lineno, file=None, line=None): (source)

Twisted-enabled wrapper around warnings.showwarning.

If file is None, the default behaviour is to emit the warning to the log system, otherwise the original warnings.showwarning Python function is called.

Parameters	message	A warning message to emit. (type: `str`)
	category	A warning category to associate with `message`. (type: `Type[Warning]`)
	filename	A file name for the source code file issuing the warning. (type: `str`)
	lineno	A line number in the source file where the warning was issued. (type: `int`)
	file	A file to write the warning message to. If `None`, write to `sys.stderr`. (type: `Optional[IO[Any]]`)
	line	A line of source code to include with the warning message. If `None`, attempt to read the line from `filename` and `lineno`. (type: `Optional[str]`)

API Documentation for Twisted, generated by pydoctor 20.12.1 at 2021-02-28 19:53:36.