@livy/rotating-file-handler

This Livy handler stores log records to files that are rotated by date/time or file size and only a limited number of files is kept.

Synchronous logger support: yes

Runtime: Node.js

Basic Example

const { RotatingFileHandler } = require('@livy/rotating-file-handler')

const handler = new RotatingFileHandler('logs-%date%.txt')

Installation

Install it via npm:

npm install @livy/rotating-file-handler

Options

The first argument to this handler's constructor is a file path to write to. It needs to contain a token based on the configured strategy.

An object of options can be passed to the constructor as the second argument.

The following options are available:

bubble

Type: boolean

Default: true

Description: Controls whether records handled by this handler should bubble up to other handlers.

See also: Bubbling

formatter

Type: FormatterInterface

Default: new LineFormatter()

Description: The formatter to use.

level

Type: LogLevel

Default: 'debug'

Description: Controls which log records should be handled based on their log level.

maxFiles

Type: number

Default: Infinity

Description: Number of log files to keep at maximum.

strategy

Type: 'max-age' | 'max-size'

Default: 'max-age'

Description: The strategy name:

• max-age: Separates log files by the date/time attached to log records thus creates a new file every year/month/day/hour/minute. It requires a %date% token in the file name.
• max-size: Separates log files by the size of the latest log file and thus creates a new file whenever the current file exceeds the size. It requires a %appendix% token in the file name.

threshold

The value this option takes varies based on the strategy option:

Strategy max-age

Type: 'minute' | 'hour' | 'day' | 'month' | 'year'

Default: 'day'

Description: The duration unit that separates individual log files. Using 'day' rotates the log files daily, using 'hour' rotates them every hour etc.

Strategy max-size

Type: number | string

Description: The file size that separates individual log files. May be a plain number of bytes or a file size string like '200 kb', '1.5M' etc.

Public API

bubble

Controls whether records handled by this handler should bubble up to other handlers. Initially set through the bubble option.

See also: Bubbling

close()

This handler implements the ClosableHandlerInterface. On cleanup, it closes the internal file handler.

You usually don't want to call this method manually. It is done automatically when a Node.js process exits / a browser page is closed.

defaultFormatter (read-only)

The formatter used by this handler if no formatter option is set.

formatter

This handler supports formatters by implementing the FormattableHandlerInterface.

level

The minimum log level of a log record to be considered by this handler. Initially set through the level option.

processors

This handler supports processors by implementing the ProcessableHandlerInterface.

reset()

This handler implements the ResettableInterface. Resetting it resets all attached processors.

You usually don't want to call this method manually on an individual handler. Consider calling it on the logger instead.