webexec

Webexec makes it easy to build a web interface for linux commands. Simply define your shell command and arguments and webexec builds a web page with a form and websocket endpoint that lets you run the command and stream its output from a web browser. You can also pause and resume a command (using SIGSTOP and SIGCONT) from the web interface.

Setup

The webexec module exports a connectHandler function that instantiates a websocket connect handler function for use with the ws websocket library:

connectHandler: function(name, command, options)

• name (string) is your command's name for display purposes
• command is an array of strings or objects making up your command
  • strings are fixed parts of the command per child_process.spawn args
  • objects of the form {name: '(field name)'} become text fields in the UI whose string value is inserted here
  • objects of the form {name: '(field name)', options: [{name: '(name)', value: '(value)'}, ...]} become select fields whose string value is inserted here
• options is an optional object with the following keys and default values:
  • cwd (string), provided to child_process.spawn, defaults to client script's own working directory
  • maxLogLength (number), in characters, of program output to store in memory; defaults to 10000

Here's an example generating a connect handler for a command that tails server logs:

var onConnect = require('webexec').connectHandler('Server Logs', [
  'tail', '-F', {
    name: 'Log',
    options: [
      {name: 'Access', value: '/var/log/nginx/access.log'},
      {name: 'Error', value: '/var/log/nginx/error.log'}
    ]
  }
]);

In addition to attaching the websocket connect handler to a ws.WebSocketServer object, you must serve the UI front-end index.html via http. The javascript on that page will connect to the websocket endpoint at the same host and path.

See server.js for a complete example of a standalone webexec server. You can launch this server by running npm start in the project directory.