Chapter 6. Using Script Modules for Dependencies and Loading Custom Functions

When executing a script from a file by using the rhq-cli.sh -f option, there is no way to define an explicit dependency within an external file. Any functions required by that script must be contained in the script or accessible to the script.

The JBoss ON CLI uses CommonJS to support script modules. CommonJS is designed as a loading mechanism to express dependencies between scripts. If a script is in the default modules directory, then the script can be loaded into the CLI session or referenced in a script, and any exported function is available to the CLI. Modules can be used to load other modules into the CLI session, as well.

The only part of a script that is exposed is a function prepended with exports (following the CommonJS convention).

For example, the sample util.js file exports a foreach function which can search for any object in JBoss ON, as generic objects, arrays, criteria (search) objects, or maps.

exports.foreach = function (obj, fn) {
  var criteriaExecutors = {
  Alert: function(criteria) { return AlertManager.findAlertsByCriteria(criteria); },
  ... 8< ...
  }

All of the functions and objects that are not exported are private and cannot be used outside the module.

A module can be loaded into another module (creating a dependency) by listing the other module as a requirement. Note that, while the .js can be present in the requirement code, the preferred method is to exclude it.

var printResults = require("modules:/modules/util");