[Feature Request] Can pass a module NOT STRING to pino transport target?

[wxqqh]

I like pino just it's light and powerfull !

[Feature Request] pass a module NOT STRING to pino transport target?

import  {dateRotateTransport} from "@/lib/utils/transport/date-rotate-transport"

pino({
   transport: {
        target: dateRotateTransport,
        options: { 
             ... // opts
        } satisfies Parameters<typeof dateRotateTransport>[0]
   }
})

There are two benefits to doing this

1. Avoid requiring within Pino. For example, during the construction and startup of Nextjs, its internal packaging tool (SWC) may not be able to correctly parse and handle the relative path of Pino Transport. When loading Transport, Pino will attempt to require or import the specified target file in a new worker thread, which often conflicts with the packaging and module parsing mechanism of Nextjs.
2. Type derivation can be improved within Pino. Make options more easily compatible with typescript

Current

Just I meet a problem:

 ⨯ Error: unable to determine transport target for "./transport/date-rotate-transport"
    at getLogger (src/lib/utils/logger.ts:58:14)
    at __TURBOPACK__module__evaluation__ (src/lib/utils/logger.ts:67:23)
    at __TURBOPACK__module__evaluation__ (src/app/[locale]/layout.tsx:15:1)
    at __TURBOPACK__module__evaluation__ (.next/server/chunks/ssr/[root-of-the-server]__daec2034._.js:7:47)
    at Object.<anonymous> (.next/server/app/[locale]/page.js:18:3)
  56 | /** Get a new logger */
  57 | export function getLogger(name = "api", level: Level = "info"): Logger {
> 58 |   return pino({
     |              ^
  59 |     transport: loggerConfig,
  60 |     name: `${PREFIX}:${name}`,
  61 |     mixin: contextMixin, {
  page: '/en/about'
}
 GET /en 500 in 3872ms
 GET /about 500 in 1715ms
 GET /_next/internal/helpers.ts 404 in 657ms

ENV:

Nextjs 15.5.2
Nodejs 24.7.0
Typescript 5.8.3

and i add this code

export const loggerConfig: LoggerOptions["transport"] = {
  targets: [
      target: "./transport/date-rotate-transport",
      options: {
        filename: `${ENV.LOG_DIR}/${PREFIX}-${ENV.LOGGER_LEVEL}-%DATE%`,
        frequency: "daily",
        date_format: "YYYY-MM-DD",
        size: "100M",
        max_logs: "10",
        extension: ".log",
        audit_file: `${ENV.LOG_DIR}/audit.json`,
      },
    }]
}

export function getLogger(name = "api", level: Level = "info"): Logger {
  return pino({
    transport: loggerConfig,
    name: `${PREFIX}:${name}`,
    mixin: contextMixin,
    level,
  })
}

files tree

➜  utils git:(main) tree .
.
├── cls-session.ts
├── database.ts
├── env.ts
├── fluentd.ts
├── logger.ts
├── partial.ts
└── transport
    ├── date-rotate-transport.ts
    ├── fluentd-transport.ts
    └── pino-log-data.ts

2 directories, 9 files

[mcollina]

Thanks for reporting.

Unfortunately it's not possible to accept a module, it's a limitation of Node.js.

As for deriving types, PRs are welcomed!

[mbrevda]

Unfortunately it's not possible to accept a module, it's a limitation of Node.js.

Can you please expound?

[mcollina]

Pino run transports as worker threads: this is required to guarantee that all your logs are correctly flushed.

Node.js requires an entry point js file for a new thread.

[mbrevda]

I see, make sense. This becomes an issue when bundling the code - bundlers won't pick up the string name and bundle the transport. Is there some way to work around this?

Would it make sense to add a function module that can return its current path/access point? This would ensure the module is accessible, and also provide a string that can be passed to the worker? Or perhaps you have a better solution?

In my use case, I only use a custom transport in development (where all the npm modules are installed anyway), so it's not a significant issue. But I would imagine this applies to many use cases

[mcollina]

You need to configure multiple entry points for your application. Here is the relevant webpack config: https://webpack.js.org/concepts/entry-points/.

[mbrevda]

A. I don't use webpack
B. Depending on the settings, the built module is likely not at the location pino is expecting to be expecting

Hence, if there was some way to share an exact path a separate entry point wouldn't be necessary and should work across bundlers with zero configuration

[mcollina]

What do you use? All bundlers I know support a similar feature.

[CHC383]

What additional entry point should be set for the Pino worker thread? I think the OP is using Turbopack as the log has __TURBOPACK__module__evaluation__, which is used by NextJs and will become the default bundler in the upcoming v16.

Similarly I ran into an issue vercel/next.js#84766 with Turbopack bundling while testing NextJs v16 Beta. The transport target and thread-stream bundling issue was resolved by setting the serverExternalPackages in NextJs config and explicit import with WebPack, but the same setup has a new issue above with Turbopack.

[jsumners]

Nothing in Pino has changed in regard to this. It sounds like you should open an issue with the other tool(s) you are using.

[CHC383]

Nothing in Pino has changed in regard to this. It sounds like you should open an issue with the other tool(s) you are using.

Yeah I already did (vercel/next.js#84766), just seeking for clarification on the statements below to see if there are workarounds for Turbopack.

Node.js requires an entry point js file for a new thread.

You need to configure multiple entry points for your application.