Logging and metrics infrastructure.
Variable | EventDict | Undocumented |
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. |
Interface | ILogObserver | An observer which can do something with log events. |
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 | err | Write a failure to the log. |
Class | Logger | This represents a class which may 'own' a log. Used by subclassing. |
Class | LogPublisher | Class for singleton log message publishing. |
Variable | theLogPublisher | Undocumented |
Function | addObserver | Add a log observer to the global publisher. |
Function | removeObserver | Remove a log observer from the global publisher. |
Function | msg | Publish a message to the global log publisher. |
Function | showwarning | Publish a Python warning through the global log publisher. |
Function | textFromEventDict | Extract text from an event dict passed to a log observer. If it cannot handle the dict, it returns None. |
Class | FileLogObserver | Log observer that writes to a file-like object. |
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 | 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. |
Class | NullFile | A file-like object that discards everything. |
Function | discardLogs | Discard messages logged via the global logfile object. |
Variable | logfile | Undocumented |
Variable | logerr | Undocumented |
Class | DefaultObserver | Default observer. |
Variable | defaultObserver | Undocumented |
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. |
Class | _GlobalStartStopObserver | Mix-in for global log observers that can start and stop. |
Utility method which wraps a function in a try:/except:, logs a failure if one occurs, and uses the system's logPrefix.
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 | 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 . (type: None , Exception , or Failure .) |
_why | The source of this failure. This will be logged along with _stuff and should describe the context in which the failure occurred. (type: str ) | |
kw | Undocumented |
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 | An object to create an alias for. (type: object ) |
Returns | a 1-argument callable that returns something (type: object ) |
Add a log observer to the global publisher.
Parameters | observer | a log observer (type: callable ) |
See Also | LogPublisher.addObserver |
Remove a log observer from the global publisher.
Parameters | observer | a log observer previously added with addObserver (type: callable ) |
See Also | LogPublisher.removeObserver |
Publish a message to the global log publisher.
Parameters | message | the log message (type: tuple of str (native string)) |
event | fields for the log event (type: dict mapping str (native string) to object ) | |
See Also | LogPublisher.msg |
Publish a Python warning through the global log publisher.
See Also | LogPublisher.showwarning |
Try to format a string, swallowing all errors to always return a string.
Parameters | fmtString | a % -format string (type: str ) |
fmtDict | string formatting arguments for fmtString (type: Dict[str, Any] ) | |
Returns | A native string, formatted from fmtString and fmtDict . (type: str ) | |
Note | For backward-compatibility reasons, this function ensures that it returns a native string, meaning bytes in Python 2 and str in Python 3. |
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 | Undocumented (type: EventDict ) |
Returns | Undocumented (type: Optional[str] ) |
Initialize logging to a specified file.
Returns | A FileLogObserver if a new observer is added, None otherwise. |
Initialize logging to a specified observer. If setStdout is true (defaults to yes), also redirect sys.stdout and sys.stderr to the specified file.