Add a prefix to the orpc/pino logs

[maelp]

Describe the feature

I'm using @orpc/experimental-pino plugin to get oRPC context in Pino.
In my logs, I'd like to prefix the message with the name of the current oRPC method, eg

[path.myMethod] My log

right now it doesn't seem to be feasible directly from pino, because it needs modifying the plugin. Could we add an option to add this feature on the experimental-pino plugin? eg some kind of pinoPlugin({prefix: (ctx) => [{ctx.method}]})

Additional information

• Would you be willing to help implement this feature?

[pullfrog]

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[dinwwwh]

Why is this needed when the method is already available on rpc.method? You can search based on that field.

[maelp]

@dinwwwh in my case it's because I want to see it as a prefix in the log message, not just for filtering, because it makes things much clearer

[dinwwwh]

@maelp You can easily prefix message with rpc.method when creating pino(...config here...)

[maelp]

@dinwwwh but I don't create the Pino logger in each rpc method, I create a global one (so I can't set a prefix there, no?) and then this global logger gets automatically configured by the oRPC pino plugin each time a method is called, so that when I do getLogger the rpc.method is set. But it won't show in the log message as a prefix, will it?

[dinwwwh]

@maelp I mean global config - you can hook before log and prefix msg with rpc.method. Correct me if I'm wrong @pullfrog

[pullfrog]

Confirmed @dinwwwh's suggestion and posted a detailed explanation on #1571. The LoggingHandlerPlugin already binds rpc.method before handler execution, so a global Pino hooks.logMethod hook can read this.bindings().rpc?.method and prefix the message automatically — no plugin changes required.

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[pullfrog]

@maelp @dinwwwh is right — you can achieve this with Pino's built-in hooks.logMethod without any plugin changes.

Since LoggingHandlerPlugin sets rpc.method on the logger bindings, a global logMethod hook can read it via this.bindings() and prefix the message:

import pino from 'pino'

const logger = pino({
  hooks: {
    logMethod(args, method, level) {
      const methodName = this.bindings().rpc?.method
      if (methodName && typeof args[0] === 'string') {
        args[0] = `[${methodName}] ${args[0]}`
      }
      else if (methodName && typeof args[0] === 'object' && args[0].msg) {
        args[0].msg = `[${methodName}] ${args[0].msg}`
      }
      method.apply(this, args)
    },
  },
})

This works because the plugin calls setBindings({ rpc: { method: 'path.to.procedure' } }) before your handler runs, so by the time you call logger.info('My log') inside a procedure, the hook sees the bound method name and prefixes it automatically.

If you need more control (e.g., custom formatting or conditional prefixes), you can wrap the logic in a small helper:

function createORPCLogger(options?: pino.LoggerOptions) {
  return pino({
    ...options,
    hooks: {
      ...options?.hooks,
      logMethod(args, method, level) {
        const rpc = this.bindings().rpc
        if (rpc?.method) {
          const prefix = `[${rpc.method}]`
          if (typeof args[0] === 'string') {
            args[0] = `${prefix} ${args[0]}`
          }
          else if (typeof args[0] === 'object') {
            args[0] = { ...args[0], msg: `${prefix} ${args[0].msg ?? ''}` }
          }
        }
        method.apply(this, args)
      },
    },
  })
}

No plugin modification needed — this is the idiomatic Pino way to transform log messages globally.

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