$ gnpm install pino-abstract-transport
pino-abstract-transport
Write Pino transports easily.
Install
npm i pino-abstract-transport
Usage
import build from 'pino-abstract-transport'
export default async function (opts) {
return build(async function (source) {
for await (let obj of source) {
console.log(obj)
}
})
}
or in CommonJS and streams:
'use strict'
const build = require('pino-abstract-transport')
module.exports = function (opts) {
return build(function (source) {
source.on('data', function (obj) {
console.log(obj)
})
})
}
Typescript usage
Install the type definitions for node. Make sure the major version of the type definitions matches the node version you are using.
Node 16
npm i -D @types/node@16
API
build(fn, opts) => Stream
Create a split2 instance and returns it.
This same instance is also passed to the given function, which is called
synchronously.
If opts.transform is true, pino-abstract-transform will
wrap the split2 instance and the returned stream using duplexify,
so they can be concatenated into multiple transports.
Events emitted
In addition to all events emitted by a Readable
stream, it emits the following events:
unknownwhere an unparsable line is found, both the line and optional error is emitted.
Options
-
parsean option to change to data format passed to build function. When this option is set tolines, the data is passed as a string, otherwise the data is passed as an object. Default:undefined. -
close(err, cb)a function that is called to shutdown the transport. It's called both on error and non-error shutdowns. It can also return a promise. In this case discard the thecbargument. -
parseLine(line)a function that is used to parse line received frompino.
Example
custom parseLine
You can allow custom parseLine from users while providing a simple and safe default parseLine.
'use strict'
const build = require('pino-abstract-transport')
function defaultParseLine (line) {
const obj = JSON.parse(line)
// property foo will be added on each line
obj.foo = 'bar'
return obj
}
module.exports = function (opts) {
const parseLine = typeof opts.parseLine === 'function' ? opts.parseLine : defaultParseLine
return build(function (source) {
source.on('data', function (obj) {
console.log(obj)
})
}, {
parseLine: parseLine
})
}
Stream concatenation / pipeline
You can pipeline multiple transports:
const build = require('pino-abstract-transport')
const { Transform, pipeline } = require('stream')
function buildTransform () {
return build(function (source) {
return new Transform({
objectMode: true,
autoDestroy: true,
transform (line, enc, cb) {
line.service = 'bob'
cb(null, JSON.stringify(line))
}
})
}, { enablePipelining: true })
}
function buildDestination () {
return build(function (source) {
source.on('data', function (obj) {
console.log(obj)
})
})
}
pipeline(process.stdin, buildTransform(), buildDestination(), function (err) {
console.log('pipeline completed!', err)
})
License
MIT
Current Tags
- 1.0.0 ... latest (2 years ago)