Multistream dedupe example in documentation does not work

[celebro]

The following example from documentation about dedupe flag in multistream (https://github.com/pinojs/pino/blob/master/docs/api.md#pino-multistream) does not work as intended, it only logs info and error, while debug and fatal are ignored.

var pino = require('pino')
var multistream = pino.multistream
var streams = [
  {stream: process.stdout},
  {level: 'error', stream: process.stderr},
]

var opts = {
    levels: {
        silent: Infinity,
        fatal: 60,
        error: 50,
        warn: 50,
        info: 30,
        debug: 20,
        trace: 10
    },
    dedupe: true,
}

var log = pino({
  level: 'debug' // this MUST be set at the lowest level of the
                // destinations
}, multistream(streams, opts))

log.debug('this will be written ONLY to process.stdout')
log.info('this will be written ONLY to process.stdout')
log.error('this will be written ONLY to process.stderr')
log.fatal('this will be written ONLY to process.stderr')

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[celebro]

I'm afraid I can't dedicate the time for implementing a fix, I can only add what I'm currently using instead is specifying a stream for every log level:

var streams = [
    { level: 'debug', stream: process.stdout },
    { level: 'info', stream: process.stdout },
    { level: 'warn', stream: process.stdout },
    { level: 'error', stream: process.stderr },
    { level: 'fatal', stream: process.stderr }
];

[bl00dhound]

Hi, there!
There are two parts of problem:

• ifdedup is set totrue log is sent to the stream with the same level only. That's the reason why we can't find log with fatal level in process.stderr stream. I've fixed it in my PR.
• if level of stream isn't set initially, info level will be set by default. So, debug logs can't put to the stream with info level. That's more complicated problem than the previous one because we need to synchronize two entities (pino-logger and multistream). pino-logger has access to streams array but multistream entity knows nothing about default level in pino-logger. Probably, as a solution, I could add a couple of lines in the documentation about independent default log level in streams. Does it make sense?

[mcollina]

should be fixed in latest master

[github-actions]

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