A central hub that receives log messages from all logup-emitters in an application.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


LogUp Hub

One logger to rule them all

This package is a central hub that receives log messages from all logup-emitters beneath it in the module tree. Use this hub in your application if you need to configure log output from libraries that use logup-emitter.

build status browser support

About LogUp

LogUp is a simple yet powerful logging system that decouples logging from configuration. Library packages use logup-emitter to write their logs, without needing to know where the log output is sent. Applications can then use logup-hub to configure the log output and decides what gets sent where.

For more information about how LogUp works, see the emitter documentation.

Configuring hub output

A LogUp hub has a collection of transports that deliver logged messages to various endpoints. These transports are configured as a set of layers that can handle or modify each message.

Layers are typically configured using a JSON array of layer configuration objects.

For example:

    { "type": "console",
      "minLevel": "warn"
    { "type": "file",
      "package": "socket.io",
      "minLevel": "trace",
      "filename": "socket.io-trace.log"
    { "type": "file",
      "source-filename": "/utils\.js$",
      "minLevel": "trace",
      "filename": "util junk.log",
      "stopPropagation": "true"
    { "type": "file",
      "packages": "socket.io: info, mysql: warn, stripe: trace, oauth: error",
      "filename": "interesting events.log"
    { "type": "filter",
      "package-author": "SLaks",
      "minLevel": "trace",
      "layers": [
          { "type": "file",
          { "type": "email",
            "minLevel": "error",

All layers can have filtering options applied; these will limit that layer to only receive messages from sources that match the filter.

To apply filtering to multiple layers, use a "type": "filter" layer, which can contain one or more child layers and will only send messages to its child layers if they meet the parent filter.