pino
Version:
super fast, all natural json logger
195 lines (177 loc) • 8.96 kB
JavaScript
const EE = require('node:events')
const { pipeline, PassThrough } = require('node:stream')
const pino = require('../pino.js')
const build = require('pino-abstract-transport')
const loadTransportStreamBuilder = require('./transport-stream')
// This file is not checked by the code coverage tool,
// as it is not reliable.
/* istanbul ignore file */
/*
* > Multiple targets & pipelines
*
*
* ┌─────────────────────────────────────────────────┐ ┌─────┐
* │ │ │ p │
* │ │ │ i │
* │ target │ │ n │
* │ │ ────────────────────────────────┼────┤ o │
* │ targets │ target │ │ . │
* │ ────────────► │ ────────────────────────────────┼────┤ m │ source
* │ │ target │ │ u │ │
* │ │ ────────────────────────────────┼────┤ l │ │write
* │ │ │ │ t │ ▼
* │ │ pipeline ┌───────────────┐ │ │ i │ ┌────────┐
* │ │ ──────────► │ PassThrough ├───┼────┤ s ├──────┤ │
* │ │ └───────────────┘ │ │ t │ write│ Thread │
* │ │ │ │ r │◄─────┤ Stream │
* │ │ pipeline ┌───────────────┐ │ │ e │ │ │
* │ │ ──────────► │ PassThrough ├───┼────┤ a │ └────────┘
* │ └───────────────┘ │ │ m │
* │ │ │ │
* └─────────────────────────────────────────────────┘ └─────┘
*
*
*
* > One single pipeline or target
*
*
* source
* │
* ┌────────────────────────────────────────────────┐ │write
* │ │ ▼
* │ │ ┌────────┐
* │ targets │ target │ │ │
* │ ────────────► │ ──────────────────────────────┤ │ │
* │ │ │ │ │
* │ ├──────┤ │
* │ │ │ │
* │ │ │ │
* │ OR │ │ │
* │ │ │ │
* │ │ │ │
* │ ┌──────────────┐ │ │ │
* │ targets │ pipeline │ │ │ │ Thread │
* │ ────────────► │ ────────────►│ PassThrough ├─┤ │ Stream │
* │ │ │ │ │ │ │
* │ └──────────────┘ │ │ │
* │ │ │ │
* │ OR │ write│ │
* │ │◄─────┤ │
* │ │ │ │
* │ ┌──────────────┐ │ │ │
* │ pipeline │ │ │ │ │
* │ ──────────────►│ PassThrough ├────────────────┤ │ │
* │ │ │ │ │ │
* │ └──────────────┘ │ └────────┘
* │ │
* │ │
* └────────────────────────────────────────────────┘
*/
module.exports = async function ({ targets, pipelines, levels, dedupe }) {
const targetStreams = []
// Process targets
if (targets && targets.length) {
targets = await Promise.all(targets.map(async (t) => {
const fn = await loadTransportStreamBuilder(t.target)
const stream = await fn(t.options)
return {
level: t.level,
stream
}
}))
targetStreams.push(...targets)
}
// Process pipelines
if (pipelines && pipelines.length) {
pipelines = await Promise.all(
pipelines.map(async (p) => {
let level
const pipeDests = await Promise.all(
p.map(async (t) => {
// level assigned to pipeline is duplicated over all its targets, just store it
level = t.level
const fn = await loadTransportStreamBuilder(t.target)
const stream = await fn(t.options)
return stream
}
))
return {
level,
stream: createPipeline(pipeDests)
}
})
)
targetStreams.push(...pipelines)
}
// Skip building the multistream step if either one single pipeline or target is defined and
// return directly the stream instance back to TreadStream.
// This is equivalent to define either:
//
// pino.transport({ target: ... })
//
// OR
//
// pino.transport({ pipeline: ... })
if (targetStreams.length === 1) {
return targetStreams[0].stream
} else {
return build(process, {
parse: 'lines',
metadata: true,
close (err, cb) {
let expected = 0
for (const transport of targetStreams) {
expected++
transport.stream.on('close', closeCb)
transport.stream.end()
}
function closeCb () {
if (--expected === 0) {
cb(err)
}
}
}
})
}
// TODO: Why split2 was not used for pipelines?
function process (stream) {
const multi = pino.multistream(targetStreams, { levels, dedupe })
// TODO manage backpressure
stream.on('data', function (chunk) {
const { lastTime, lastMsg, lastObj, lastLevel } = this
multi.lastLevel = lastLevel
multi.lastTime = lastTime
multi.lastMsg = lastMsg
multi.lastObj = lastObj
// TODO handle backpressure
multi.write(chunk + '\n')
})
}
/**
* Creates a pipeline using the provided streams and return an instance of `PassThrough` stream
* as a source for the pipeline.
*
* @param {(TransformStream|WritableStream)[]} streams An array of streams.
* All intermediate streams in the array *MUST* be `Transform` streams and only the last one `Writable`.
* @returns A `PassThrough` stream instance representing the source stream of the pipeline
*/
function createPipeline (streams) {
const ee = new EE()
const stream = new PassThrough({
autoDestroy: true,
destroy (_, cb) {
ee.on('error', cb)
ee.on('closed', cb)
}
})
pipeline(stream, ...streams, function (err) {
if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') {
ee.emit('error', err)
return
}
ee.emit('closed')
})
return stream
}
}