…r (bobvandevijver)

This PR was squashed before being merged into the 4.2-dev branch (closes #27157).

Discussion
----------

[DI] Select specific key from an array resolved env var

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | Discussed in #25643    <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#9734 <!-- required for new features -->

<!--
Write a short README entry for your feature/bugfix here (replace this comment block.)
This will help people understand your PR and can be used as a start of the Doc PR.
Additionally:
 - Bug fixes must be submitted against the lowest branch where they apply
   (lowest branches are regularly merged to upper ones so they get the fixes too).
 - Features and deprecations must be submitted against the master branch.
-->

As discussed in #25643, it would be convenient to have an key processor for environment variables which have been read from for example a JSON file.

The main advantage of this feature lies in specifying a single file for your secrets, that can be directly used in your configuration, without leaking them into your env.

## Example
**.secrets.json**
```json
{
  "database_password": "xxx"
}
```
**.env**
```env
APP_SECRETS=/opt/application/.secrets.json
DATABASE_URL=mysql://myuser:%database_password%@localhost:3306/mydb
```
**services.yaml**
```yaml
parameters:
  database_password: '%env(key:database_password:json:file:APP_SECRETS)%'
```

This example configuration will result in a `database_password` parameter being filled with `xxx`, and due to Doctrine defaults, the database url will be resolved with the correct password.

Commits
-------

42186a2bac [DI] Select specific key from an array resolved env var

…r (bobvandevijver)

This PR was squashed before being merged into the 4.2-dev branch (closes #27157).

Discussion
----------

[DI] Select specific key from an array resolved env var

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | Discussed in #25643    <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#9734 <!-- required for new features -->

<!--
Write a short README entry for your feature/bugfix here (replace this comment block.)
This will help people understand your PR and can be used as a start of the Doc PR.
Additionally:
 - Bug fixes must be submitted against the lowest branch where they apply
   (lowest branches are regularly merged to upper ones so they get the fixes too).
 - Features and deprecations must be submitted against the master branch.
-->

As discussed in #25643, it would be convenient to have an key processor for environment variables which have been read from for example a JSON file.

The main advantage of this feature lies in specifying a single file for your secrets, that can be directly used in your configuration, without leaking them into your env.

## Example
**.secrets.json**
```json
{
  "database_password": "xxx"
}
```
**.env**
```env
APP_SECRETS=/opt/application/.secrets.json
DATABASE_URL=mysql://myuser:%database_password%@localhost:3306/mydb
```
**services.yaml**
```yaml
parameters:
  database_password: '%env(key:database_password:json:file:APP_SECRETS)%'
```

This example configuration will result in a `database_password` parameter being filled with `xxx`, and due to Doctrine defaults, the database url will be resolved with the correct password.

Commits
-------

42186a2 [DI] Select specific key from an array resolved env var

…guiluz)

This PR was merged into the master branch.

Discussion
----------

Added key env processor to docs

Not much more to say, this is documenting the feature added in symfony/symfony#27157.

Fixes #9734.

Commits
-------

9c91cf1 Reworded and added other config formats
1d72bc2 Added key env processor to docs