pino-arborsculpture

Lead maintainer: jsumners

pino-arborsculpture is a module that allows you to change the logging level of a Pino logger, or set of loggers (e.g. child loggers) while your process is running. It accomplishes this by monitoring a specified file for changes and acts accordingly.

Example

'use strict'

const Arborsculpt = require('pino-arborsculpture')
const pino = require('pino')
const log = pino() // info level by default

const arbor = new Arborsculpt({
  path: '/tmp/adjustments.json',
  loggers: [log],
  interval: 60_000 // the default
})

arbor.on('error', function (err) {
  // there was a problem reading the file or setting the level
})

At some point you decide log should be set to the debug level because production is broken, and you have to figure out why without taking it offline, so you create the /tmp/adjustments.json file:

{
  "level": "debug"
}

Within one minute of creating the file, your process will start outputting debug level log lines.

Options

• path [optional]: string pointing to the file that will be monitored. This file does not need to exist until such time as you are ready to change levels in your process. Default: os.tmpdir() + 'aborsculpt.json'
• loggers [required]: an array of Pino instances to adjust. Default: []
• interval [optional]: the number of milliseconds between scans of the specified file. Default: 60_000

Level Change File Format

The file being monitored must be a valid JSON file. It can contain two possible formats:

{"level": "levelName"}

or

{
  "levels": [
    "levelName",
    "levelName"
  ]
}

In the first case, the single level will be applied to all loggers supplied at construction. In the second case, each level will be applied to the corresponding logger in the loggers array. Note: if you supplied 5 loggers at construction, but only 3 in the file, then only the first 3 loggers will have their levels changed. But be aware, Pino will change the level of child loggers when the parent logger's level is changed.

All level names must be valid level names as registered with the target Pino instances.

License

MIT License