pino-stream

Lead maintainer: alexandrevoilab

This module provides a child process utility for pino. It aims to be compatible with existing pino transports.

This is not a transport for pino by itself. Given a tranport list, it will spawn a new child process and run the transport inside the new process. This is similar to running node app.js | pino-transport.

Might not be production ready. This module as not been battle tested yet. See the TODO section.

Attribution

This module is inspired by pino-spawn and the following issues: pinojs/community#3 and atis--/pino-spawn#1.

Install

$ npm install pino-stream --save

Usage

Basic exemple usage with pino-elasticsearch and sole transport. Note, you have to npm install pino-elasticsearch before.

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream(['pino-elasticsearch'])
);

Options

pino_stream() only takes one argument: an array of streams or modules to stream to. Every element in that array SHOULD be an object with the following properties.

The object MUST have only one of stream or module.

stream (stream.Writable)

A stream.Writable instance. Logs will be .pipe()ed directly to it.

module (string)

The name of a pino transport module. Not the require()ed module, just the name. pino-stream will spawn a new process to host the module and stream logs to it.

Should work with any pino transport listed on the official pino transport documentation.

args (array)

If the object describe a module, this will be the arguments passed to it.

See nodejs child_process.fork documentation.

Shorthands

Shorthand configurations are supported. An object will be used a stream and a string will be used as a module.

pino_stream([{
    module: 'pino-elasticsearch'
  }, {
    stream: process.stdout
  }
])

Is the same as

pino_stream(['pino-elasticsearch', process.stdout])

Exemples

One transport

Simple pipe pino-elasticsearch with no arguments.

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream([{
    module: 'pino-elasticsearch'
  }])
);

Short:

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream(['pino-elasticsearch'])
);

One transport and one stream

Pipe pino-elasticsearch with an external elasticsearch server and logs to stdout.

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream([
    {
      module: 'pino-elasticsearch',
      args: ['--host', '10.20.30.40', '--index', 'myindex']
    },
    {
      stream: process.stdout
    }
  ])
);

Short:

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream([
    {
      module: 'pino-elasticsearch',
      args: ['--host', '10.20.30.40', '--index', 'myindex']
    },
    process.stdout
  ])
);

One transport and pretty print

Simple pipe pino-elasticsearch with no arguments and pretty print to stdout.

'use strict';

const pino_stream = require('pino-stream');
const pretty = require('pino').pretty();

pretty.pipe(process.stdout);

let pino = require('pino')(
  pino_stream([
    {
      module: 'pino-elasticsearch'
    },
    {
      stream: pretty
    }
  ])
);

Short:

'use strict';

const pino_stream = require('pino-stream');
const pretty = require('pino').pretty();

pretty.pipe(process.stdout);

let pino = require('pino')(
  pino_stream(['pino-elasticsearch', pretty])
);

No transport

Useless, but it will not crash. All logs will be piped to process.stdout.

'use strict';

const pino_stream = require('pino-stream');

let pino = require('pino')(
  pino_stream()
);

TODO

PRs are welcome!

• Add benchmarks
• Add unit tests
• Test on high loads
• Test in backpressure situations
• Restart crashed child process
• Add a level filter for every output

License

MIT License