Contributed by
Nicolas Grekas
in #23901.
Symfony 4 will promote and leverage environment variables to configure some parts of the applications. In Symfony 3.4 we're working hard to make that fully possible. The last big hurdle was that environment variables are always transformed into strings. That's a big problem when using PHP 7.1 type-hints:
1 2 3 4 | public function connect(string hostname, int port)
{
// ...
}
|
If the value of the port
argument is obtained through an env var, the
application won't work because the argument will be a string instead of the
expected integer:
1 2 | parameters:
app.connection.port: '%env(DATABASE_PORT)%'
|
In Symfony 3.4 we improved the processing of environment variables to support type casting. When referencing an env var, you can now set the type you want its value converted to:
1 2 3 | parameters:
# roughly equivalent to "(int) getenv('DATABASE_PORT')"
app.connection.port: '%env(int:DATABASE_PORT)%'
|
We included support for the usual bool:
, int:
, float:
and
string:
casting. But we didn't stop there! We also added some utilities to
perform the most common operations related to env vars (and you can combine
them all).
The resolve:
operator replaces container parameter names by their values:
1 2 3 4 | parameters:
project_dir: '/foo/bar'
env(DB): 'sqlite://%%project_dir%%/var/data.db'
db_dsn: '%env(resolve:DB)%'
|
The file:
operator gets the contents of the given file and the json:
operator decodes the given contents into a PHP array, so you can combine them
to get the secrets stored in some file:
1 2 3 | parameters:
env(SECRETS_FILE): '/etc/secure/example.com/secrets.json'
app.secrets: '%env(json:file:SECRETS_FILE)%'
|
The base64:
operator decodes the given base64 content and const:
allows
you to refer to any PHP constant:
1 2 3 4 5 6 | parameters:
env(SOME_VALUE): 'NWE3OWExYzg2NmVmZWY5Y2ExODAwZjk3MWQ2ODlmM2U='
app.some_value: '%env(base64:SOME_VALUE)%'
env(NUM_ITEMS): 'App\\Entity\\BlogPost::NUM_ITEMS'
app.num_items: '%env(constant:NUM_ITEMS)%'
|
Last but not least, you can define your own operators to manipulate the
content of the environment variables before using them. To do so, define a
service implementing the new EnvProviderInterface
and tag it with
container.env_provider
.
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