asynchronous.md

Asynchronous Logging

In essence, asynchronous logging enables the minimum overhead of Pino. Asynchronous logging works by buffering log messages and writing them in larger chunks.

const pino = require('pino')
const logger = pino(pino.destination({
  dest: './my-file', // omit for stdout
  minLength: 4096, // Buffer before writing
  sync: false // Asynchronous logging
}))

It's always possible to turn on synchronous logging by passing sync: true. In this mode of operation log messages are directly written to the output stream, as the messages are generated with a blocking operation.

• See pino.destination
• pino.destination is implemented on sonic-boom ⇗.

AWS Lambda

Asynchronous logging is disabled by default on AWS Lambda, or any other environment that modifies process.stdout. If forcefully turned on, we recommend to call dest.flushSync() at the end of each function execution to avoid losing data.

Caveats

Asynchronous logging has a couple of important caveats:

• As opposed to the default mode, there is not a one-to-one relationship between calls to logging methods (e.g. logger.info) and writes to a log file
• There is a possibility of the most recently buffered log messages being lost in case of a system failure, e.g. a power cut.

See also:

• pino.destination api
• destination parameter