nodejs-dashboard

Telemetry dashboard for node.js apps from the terminal!

Determine in realtime what's happening inside your node process from the terminal. No need to instrument code to get the deets. Also splits stderr/stdout to help spot errors sooner.

NOTE: This module isn't designed for production use and should be limited to development environments.

Install

The preferred method is global install. npm install -g nodejs-dashboard

Local install works also; just use ./node_modules/.bin/nodejs-dashboard instead of nodejs-dashboard to execute.

Setup

The dashboard agent needs to be required by your app. There are two ways to do this:

Including via code

From within a dev.index.js script or other dev entry point simply require the nodejs-dashboard module.

// dev.index.js
require("nodejs-dashboard");
require("./index");

To launch: nodejs-dashboard node dev.index.js

Including via preload argument

This method utilizes Node's -r flag to introduce the nodejs-dashboard module. In this setup no code modifications are required. This is functionally equivalent to the above example.

To launch: nodejs-dashboard -- node -r nodejs-dashboard index.js

Fonts

nodejs-dashboard uses the Braille Unicode character set to show graphs via the node-drawille dependancy. Ensure your terminal program's font supports this character set.

Environment variables

nodejs-dashboard uses several environment variables to modify its behavior. These include some required values to prevent mangled output.

Usage

Press ? to see a list of keybindings. Use arrow keys to change the layout.

You may want to add an npm script to to your package.json to launch your app using nodejs-dashboard using one of the options above. Example:

"scripts": {
  "dev": "nodejs-dashboard -- node -r nodejs-dashboard index.js"
}

Passing arguments

If your app requires additional arguments you'll need to use the -- flag to separate them from nodejs-dashboard options. For example:

nodejs-dashboard --port=8002 -- node -m=false --bar=true index.js

Launching your app with something other than node

Most CLI interfaces provide a mechanism for launching other tools. If you're looking to use something like nodemon or babel checkout the exec options provided by the CLI.

% nodemon --exec "nodejs-dashboard babel-node" src/index.js

Docker and Docker Compose support

nodejs-dashboard can run inside a container if that container has a TTY allocated to it. The Docker documentation shows how to run a container with an interactive terminal session. Additional the Docker Compose documentation indicates that docker-compose run defaults to allocating a TTY and docker-compose up defaults to not allocating one.

CLI options

Usage: nodejs-dashboard [options] -- [node] [script] [arguments]

Options:
  -h, --help                  output usage information
  -e, --eventdelay [ms]       Minimum threshold for event loop reporting, default 10ms
  -l, --layouts [file]        Path to file or npm module with layouts
  -p, --port [port]           Socket listener port
  -r, --refreshinterval [ms]  Metrics refresh interval, default 1000ms
  -s, --settings [settings]   Overrides layout settings for given view types           
  -V, --version               output the version number

--eventdelay

This tunes the minimum threshold for reporting event loop delays. The default value is 10ms. Any delay below this value will be reported at 0.

--layouts

Optionally supply a custom layout configuration (for details, see Customizing Layouts). Default: lib/default-layout-config.js

--port

Under the hood the dashboard utilizes SocketIO with a default port of 9838. If this conflicts with an existing service you can optionally change this value.

--refreshinterval

Specifies the interval in milliseconds that the metrics should be refreshed. The default is 1000 ms (1 second).

--settings

Overrides default or layout settings for views. Option value settings should have a format <view_type.setting.path>=<value>,.... For example --settings log.scrollback=100 will override scrollback setting for any view of log type (nested paths can be used if needed). For details about layouts, see Customizing Layouts).