cubejs/context-config-node

An advanced configuration lookup utility

context-config-node

• ConfigurationBuilder allows reading/writing configs using local or remote storage. Single API is used in both cases which makes it easier to work with the class. This is the only class users should be using directly to utilize all functionality provided by the module. ConfigurationBuilder uses the following classes underneath:
  • ContextConfiguration is an advanced configuration lookup utility. The main feature is to look for best match of the same keywords, given a list of additional contexts. Compared with config.get(key), it provides config.get(key, contexts, default).
    • ForwardConfiguration is a proxy which stores an array of ContextConfigurations and forwards get(key) requests to elements of that array. It allows notifying users about changes in configs using 'change' event on EventEmitter.
    • NodeConfig is used to work with configs stored in local file system. It is a wrapper of node-config library

API

Function	Description
ConfigurationBuilder
require('context-config').ConfigurationBuilder	importing the constructor
new ConfigurationBuilder(emitter)	constructor accepts an EventEmitter and will emit 'config-read' event when new config is read
build(context, ref)	ref object lists properties of the app whose configs we want to load (can contain properties domain, target, project, config, and version). Returns a promise.

Usage

ConfigurationBuilder

create a new instance of ConfigurationBuilder

var ConfigurationBuilder = require('context-config').ConfigurationBuilder;
var builder = new ConfigurationBuilder(emitter);

call build method to load the config which in turn returns a promise.

builder.build(context, ref)
.then(function(config){
	// use the config
	console.log(config.get('key'));
})
.fail(function(error){
	// handle the error
	console.log(error.stack);
})
.done();

ContextConfiguration

create a new instance of ContextConfiguration

var ContextConfiguration = require('context-config').ContextConfiguration;
var config = new ContextConfiguration([],[]);

append new values to the config

// without context
config.append({
	"key":"k1",
	"value":"v1"
});
// with context
config.append({
    "key":"k1",
    "context": {"site":"en-US"},
    "value":"v2"
});

get values using a key

// without a context
config.get("k1");	// should return "v1"
// with a context
config.get("k1", [{"site":"en-US"}]);	// should return "v2"