epdoc-config

Config loader and validator.

The epdoc-config library provides a mechanism to load environment-specific config settings that are merged from a list of json config files that you specify. JSON config files are loaded in order, with the later files overwriting earlier settings. JSON config files may contain a configExt (config extension) to reference another config file to load. Config files added in this manner are loaded, in the order they are encountered, after all previous config files are loaded. This allows a config file to specify a chain of config files to be loaded.

Within each config file, the loader will first load config settings from the object named defaults, and will then load settings from the object specified by the first parameter of the init method (usually this is ENV development or production). The end result is a single config object that is merged from the various sources.

JSON Config File Syntax

Example config JSON file:

{
    "production": {
        "dbName": "test",
        "db:org": {
            "driver": "mysql",
            "host": "10.179.6.27"
        }
    },
    "development": {
        "dbName": "dev.db"
    },
    "defaults": {
        "dbName": "test",
        "logFile": "${HOME}/log/${DATE}_${PID}_console.log"
    }
}

How to use this module in your application

Install the node package.

npm install epdoc-config

Initialize once on launch.

var Config = require('epdoc-config');
var moment = require('moment');
var env = 'development';
var files = ['path/to/project.settings.json'];
var opts = {
    replace: {
        home: "/User/bob",
        app: "/User/bob/dev/myproject",
        date: moment(logger.getStartTime()).format('YYYYMMDD_HHmmss'),
        pid: process.pid
    }
};

// Read the config files and replace instances of '${HOME}', etc with the values in opts.replace 
Config.init(env,files,opts);
// Now get the constructed config object
var config = Config.get();

Once initialized, access the config file from elsewhere in your code:

var config = require('epdoc-config').get();

API

init

Initialize and return config settings, reading from a list of config files, with the last file in the list overwriting previous files. If configExt is found to be set to a string or arrays of strings in any of the loaded config files, then the array of all extended config files will be loaded once the initial list of config files is loaded.

Parameters

• env Environment NODE_ENV, usually one of development, production, staging, test.
• configFileList List of config files to load
• options An object with the following properties: ** replace An object with key, value pairs where ${KEY} is to be replaced with value in all config strings. key is made uppercase. ** flat Support loading flat files that do not have 'defaults' and 'env' subsections. If the file does not contain a section named 'defaults', a section named for the specified environment, or a top level entry"_type": "tree", then the file is loaded as a flat file. To ensure that files that are not flat get loaded properly, please always ensure that they contain a 'defaults' section or that the top level object contains the property "_type": "tree".

Returns

The Config object.

Example:

var Config = require('epdoc-config').init('staging',['path/to/project.settings.json']);

get

Return the resultant config settings. Must call init() before calling this method.

Returns

The resultant config settings, resolved by loading from the list of config files.

Example:

var config = Config.get();

extend

Copy all of the properties in the source objects over to the config object, and return the config object. It's in-order, so the source will override properties of the same name in previous config.

Returns

The resultant config settings.

Example:

var config = Config.extend({url:"http://my/path"});