Multi tenant simple config for node.js. Based on TJ's config gist.

config.coffee

#
# Server config (based on tenant config)
#

# load the config from root of project
config = require __dirname + '/../../config.json'

#
# Apply defaults to every tenant up front to make things easier later.
#
for own tenantKey, tenantConfig of config
  if tenantKey.indexOf('_') is 0 then continue
  for own configKey, configValue of config[tenantKey]
    config[tenantKey][configKey] ?= config._default[configKey]

#
# Return configKey from tenantKey.
# e.g. ('meow', 'dbUrl') -> return 'mongo://meow:pants/catbox'
# We can also return the whole config or a tenant specific configuration
# e.g. () -> return config // returns the whole config.json 
# e.g. ('meow') -> return config.meowTenant // returns the json object under the tenant
#
module.exports = (tenantKey, configKey) ->
  if not tenantKey then return config
  if not config[tenantKey] then throw new Error('invalid tenant "' + tenantKey + '"')
  if not configKey then return config[tenantKey]
  if not config[tenantKey][configKey] then throw new Error('invalid config key "' + tenantKey + ':' + configKey + '"')
  return config[tenantKey][configKey]

config.json

{
	"_define": {
		"dbUrl": "the mongodb url with username and password and database name (mongolab)",
		"sendEmailOnError": "if the app should send an email when an error is encountered (node-mailer)",
		"sessionSecret": "the key to hash session tokens and restore them (used by connect / express)",
	},
	"_default": {
		"sendEmailOnError": true
		"sessionSecret": "MeowSuperDog!"
	},
	"meow": {
		"dbUrl": "mongodb://user:pass@happy.mongohq.com:9277/rawr"
	},
	"woof": {
		"dbUrl": "mongodb://user:pass@happy.mongohq.com:9277/rawr",
		"sendEmailOnError": false
	},
	"test": {
		"dbUrl": "mongodb://user:pass@happy.mongohq.com:9277/rawr",
		"sendEmailOnError": false
	}
}