A simple duplex stream transport for winston to enable streaming usage.

Winston's documentation makes it seems like streaming should work out of the box but in reality it requires at least one transport that implements the stream function. Additionally, out of the built-in transports only file and http implement this function while console and stream (shockingly) lack it. So the only transports that could use streaming also require either IO or an HTTP server at the other end which isn't super useful if you don't want or need those.

There are also no existing, simple, transports that implement it so, until now, you were stuck figuring out how to roll your own. winston-duplex solves this by providing the bare minimum required in a transport to get streaming functionality working as you'd expect.

npm install winston-duplex --save

import {DuplexTransport} from 'duplex-transport';

// no configuration necessary
const myNewTransport = new DuplexTransport();

// with configuration
const myConfiguredTransport = new DuplexTransport({
    stream: Duplex | TransformOptions,
    dump: boolean,
    name: 'myNamedTransport'
});

logger.add(myConfiguredTransport);

// prints log object to console
// IE logger.info('test');
logger.stream().on('data', (logObj) => console.log(logObj));

All options are optional:

• stream
  • undefined -- a new Transform stream using objectMode is created that passes data straight to output
  • TransportStreamOptions -- an object of options used to instantiate a new Transform stream
  • Duplex object -- The Duplex stream you want to use in the transport
• dump -- boolean (defaults to false)
  • When true the stream will be immediately consumed by an empty event listener. Useful to prevent backpressure.
  • Using false will cause the stream to buffer winston logs until it is consumed by invoking logger.stream(). Useful if you need to keep a history of logs between adding the transport and invoking the stream.
• name -- an identifier for this transport appended to the transports array in the object returned from the log event listener.

MIT