ecentria/dynamic-parameters-bundle

Runtime retrieval of parameters from environment variables for Symfony

DynamicParametersBundle

Inspired by incenteev/dynamic-parameters-bundle and %env()% parameters in Symfony 3.2., _(*1)

This bundle provides a way to read parameters from environment variables at runtime in Symfony 2.7 (and up) the same way as in Symfony 3.2 (some limitations apply)., _(*2)

, _(*3)

Installation

Installation is a 2 step process:, _(*4)

1. Download Ecentria fork of IncenteevDynamicParametersBundle
2. Enable the bundle

Step 1: Install bundle with composer

Run the following composer require command:, _(*5)

$ composer require ecentria/dynamic-parameters-bundle

Step 2: Enable the bundle

Finally, enable the bundle in the kernel:, _(*6)

// app/AppKernel.php

public function registerBundles()
{
    $bundles = array(
        // ...
        new Incenteev\DynamicParametersBundle\IncenteevDynamicParametersBundle(),
    );
}

Usage

It's highly recommended to use %env()% parameters only as a value for regular parameter:, _(*7)

# app/config/parameters.yml
parameters:
    database_host: %env(DATABASE_HOST)%

and then database_host can be used in following scenarios:, _(*8)

parameters:
    # can be concatenated with strings/parameters
    dsn: mysql:host=%database_host%;dbname=testdb

    # can be used in array
    hosts:
        - localhost
        - %database_host%

# can be used in config
doctrine:
    dbal:
        connections:
            default:
                host: %database_host%

# can be used as service argument
services:
    foo:
        class: stdClass
        arguments:
            - %database_host%

Using %env(DATABASE_HOST)% directly (instead of %database_host%) has several disadvantages:, _(*9)

1. Environment variable name DATABASE_HOST is duplicated whenever dynamic parameter is used
2. This use case is not covered with tests as much as recommended one (yet), something might not work as expected

Retrieving parameters at runtime

The bundle takes care of service arguments, but changing the behavior of $container->getParameter() is not possible. However, it exposes a service to get parameters taking the environment variables into account., _(*10)

$this->get('incenteev_dynamic_parameters.retriever')->get('database_host');

Default values for dynamic parameters

There are two options, _(*11)

(Recommended) Option 1: Using .env file (see vlucas/phpdotenv)

# .env file in project root
DATABASE_HOST="localhost"

This option is forward compatible with Symfony 3.2., _(*12)

Option 2: Using %default_env()% parameters

parameters:
    database_host: %env(DATABASE_HOST)%
    default_env(DATABASE_HOST): localhost

This option is not forward compatible with Symfony 3.2, where default values are defined as follows:, _(*13)

parameters:
    database_host: %env(DATABASE_HOST)%
    env(DATABASE_HOST): localhost # doesn't work before Symfony 3.2

Limitations

• Getting a parameter from the container directly at runtime will not use the environment variable
• Uppercase names should be used for environment variables