loggero

loggero

Lightweight stream based logger

Examples

A few examples can be found here.

API

Logger comes with a default logger instance called global.

create(name, options)

Factory method to create loggers with a particular name. Options are

1. enabled [boolean] - Flag to create the logger in a enabled/disabled state. Default - true.
2. stream [WritableStream] - Stream to write messages to. If a stream isn't provided, the global logger's stream will be used, which defaults to console. Default - undefined.
3. level [levels] - Minimum level for messages to be logged. If a level isn't provided, the global logger's level will be used, which defaults to info. Default - undefined.

var loggero = require('loggero');
 
var logger = loggero.create('OhWoW', {
  enabled: false,
  level: loggero.levels.warn
});

levels

levels are enums that represent a threshold for logging messages. Meaning, that only messages of equal or higher level will be logged. The lowest level is info and the highest level is error. If custom levels are used, they will follow the same processing logic for determing if a particular message should be logged. For custom levels, you will need to specfy values higher than error which is 3.

The different values are

1. info - alias log.
2. warn.
3. error.

The following example we configure the global logger to log warnings and errors. Also a few messages are logged to illustrate the logging interface.

var logger = require('loggero');

logger
  .level(logger.levels.warn)
  .log('Message 1')
  .warn('Warning 1')
  .error('Error 1');

find(name)

Method to find a logger by name.

In the example below, we search for the logger called OhWoW, configure its logging level, and log a few messages.

var logger = require('loggero');

logger
  .find('OhWoW')
  .level(logger.levels.info)
  .log('Message 1')
  .warn('Warning 1')
  .error('Error 1');

pipe(stream)

Method to setup the stream the logger writes to. Currently, a logger can only have one stream.

The example below shows how the default global logger is piped to JSONStream, and then piped to process.stdout. The output format is JSONLines.

var JSONStream = require('JSONStream');
var logger = require('loggero');

logger
  .pipe(JSONStream.stringify(false))
  .pipe(process.stdout);

logger
  .warn('A warning', 'cup cakes are low')
  .error('An error', 'cup cakes ran out', 'buy more')
  .log('message 12');

write(level, data)

Generic method to log messages. Call this if you are looking to write messages with a custom level. This method is what logger uses internally to log messages, warnings, and errors.

log(message, ...)

Method to log info messages.

info(message, ...)

Alias for the log method. Use whichever is more suitable for your taste.

warn(message, ...)

Method to log warnings.

error(message, ...)

Method to log errors.

enable()

Method to enable message logging.

disable()

Method to disable messages logging.

only()

Method to quickly disable ALL logger but the logger only() was called on. Only one logger can be set to only. If one is already set to only, the call is a noop.

all()

Method that removes the only filter.

enableAll()

Method to enable all loggers; global enable. When this is called, all logger will log. only and level will still determine whether or not a logger instance can actually log a message.

disableAll()

This disables the global enable flag. If this is called, then no logger will be able to log messages of any kind.

level(level)

Minimum level a message must have in order to be logged. For example, if the current level is warn, the only warn and error will be logged. Please see levels for the list of values.

Licensed under MIT