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  • License MIT

A nice little helper for retrieving configuration from environment variable

Package Exports

  • common-env
  • common-env/withLogger

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (common-env) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

common-env

Build Status Deps Version

A little helper I use everywhere for configuration. Environment variables are a really great way to quickly change a program behavior.

npm

npm install common-env

env.getOrDie(envVarName)

env.getOrElse(envVarName, default)

env.getOrElseAll(object)

var logger = console;
var env = require('common-env')();

// AMQP_LOGIN=plop AMQP_CONNECT=true AMQP_EXCHANGES[0]_NAME=new_exchange node test.js
var config = env.getOrElseAll({
  amqp: {
    login: 'guest',
    password: 'guest',
    host: 'localhost',
    port: 5672,
    connect: false,
    exchanges:[{
      name: 'first_exchange'
    },{
      name: 'second_exchange'
    }]
  },

  FULL_UPPER_CASE: {
    PORT: 8080
  },

  MICROSTATS: {
    HASHKEY: 'B:mx:global'
  }
});

t.strictEqual(config.amqp.login, 'plop'); // converted from env
t.strictEqual(config.amqp.port, 5672);
t.strictEqual(config.amqp.connect, true); // converted from env
t.strictEqual(config.amqp.exchanges[0].name, 'new_exchange'); // extracted from env
t.strictEqual(config.FULL_UPPER_CASE.PORT, 8080);

env.on('env:fallback', f(key, $default))

env.on('env:found', f(key, value, $default))

// let set NODE_ENV was set to "production"

var config = env
      .on('env:found', function (fullKeyName, value) {
        console.log('[env] %s was defined, using: %s', fullKeyName, String(value));
        doneAfterTwoCall();
      })
      .on('env:fallback', function (fullKeyName, $default) {
        console.log('[env] %s was not defined, using default: %s', fullKeyName, String($default));
        doneAfterTwoCall();
      })
      .getOrElseAll({
        node: {
          env: 'production'
        },
        a: {
          b: 'ok'
        }
      });

// Will print

// [env] NODE_ENV was defined, using: production
// [env] A_B was not defined, using default: ok

Specifying multiple aliases

It's sometimes useful to be able to specify aliases, for instance Clever-cloud or Heroku expose their own environment variable names while your application's internal code may not want to rely on them. You may not want to depend on your hosting provider conventions.

Common-env adds a layer of indirection enabling you to specify environment aliases that won't impact your codebase.

Usage

var config = env.getOrElseAll({
  amqp: {
    login: {
      $default: 'guest',
      $aliases: ['ADDON_RABBITMQ_LOGIN', 'LOCAL_RABBITMQ_LOGIN']
    },
    password: 'guest',
    host: 'localhost',
    port: 5672
  }
});

t.strictEqual(config.amqp.login, 'plop'); // converted from env

How common-env resolves config.amqp.login

  • Common-env will first read ADDON_RABBITMQ_LOGIN environment variable, if it exists, its value will be used.
  • If not common-env will read LOCAL_RABBITMQ_LOGIN, if it exists, its value will be used.
  • If not common-env will read AMQP_LOGIN, if it exists, its value will be used.
  • If not common-env will fallback on $default value.

How to retrieve old common-env logging behaviour

Common-env 1.x.x-2.x.x was displaying logs, here is how to retrieve the same behaviour in 3.x.x.

var logger = console;
var config = require('common-env/withLogger')(logger).getOrElseAll({
  amqp: {
    login: {
      $default: 'guest',
      $aliases: ['ADDON_RABBITMQ_LOGIN', 'LOCAL_RABBITMQ_LOGIN']
    },
    password: 'guest',
    host: 'localhost',
    port: 5672
  }
});

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