codeite / sp-conf

SP Conf

SimPle CONFig

A small component for reading config. It will log all the variables your are reading so you can see what values your app it using. It will also check where any variables are missing and allow your to respond.

Gettings Started

$ npm install sp-conf --save

How to use

Check out example.js that shows an example of using it.

const conf = require('sp-conf')

const regexForIpV4Address = /^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$/

const myconfig = {
  port: conf.readNumber('PORT', {defaultValue: 8080}),
  user: conf.readString(['CURRENT_USER', 'DEFAULT_USER']),
  serviceUrl: conf.readUrl('SERVICE_URL'),
  database: {
    host: conf.readString('DB_HOST_IP', {validator: regexForIpV4Address}),
    port: conf.readNumber('DB_PORT'),
    username: conf.readString('DB_USERNAME'),
    password: conf.readPassword('DB_PASSWORD'),
    keepConnectionOpen: conf.readBool('KEEP_CONNECTION_OPEN'),
  }
}

conf.makeClonableAndDeepFreeze(myconfig)

if (conf.missingEnvVars) {
  console.error('Some required env vars were missing. Terminating')
  process.exit(1)
}

const mockConfig = conf.cloneAndRefreeze(x => x.user = 'test_user')

// mockConfig would be frozan and mockConfig.user would contain 'test_user'
console.log(mockConfig.user)

module.exports = myconfig

Options common to all methods

• defaultValue - The value to use if the specified value is not available

• validator - A regular expressing to specify the format of the input value

• log - A function that logs about reading env var. Defaults to logging to stdout. E.g. To log messages with a prefix:

log: msg => console.log('message:', msg)

• error - A function that reports errors while reading env var. Defaults to logging to stderr. E.g. To log errors with a prefix:

error: err => console.error('error:', err)

• source - The object to read env vars from. Defaults to process.env

Global options

You can set global options by creating an instance rather than using the default object and passing them in.

E.g. To supress all logging:

const conf = require('sp-conf')({
  log: () => {}
})

Methods available

• readNumber - Read a number and complain if its not a number

• readString - Read a string not applying any special rules

• readPassword - Read a string but will obfuscate when logging the value out

• readUrl - Read a URL and will obfuscate the password if the URL contains one.

• readBool - Read a boolean and complain if it's not valid. Epected characters are:

  • truthy values - "true", "t", "on", "1"
  • falsy falues - "false", "f", "off", "0" It is not case sensitive so, for example, both "True" and "TRUE" work just fine

Deep freeze

deepFreezeAndMakeClonable This will freeze all the properties on your object as well as sub objects. It will also add a cloneAndRefreeze property to the object that, when called, will create a clone. The clone will also be frozen.

If you want to mutate the clone, when calling cloneAndRefreeze pass a callback with an argument that gets access to the clone before it is frozen.