Hello Symfony ;),

I'm working on a Symfony project that is hosted on Platform.sh and uses Redis as a service.
During local development, I am able to use the REDIS_URL environment variable in my Symfony configuration as follows:

framework:
  cache:
    app: cache.adapter.redis_tag_aware
    system: cache.adapter.redis
    default_redis_provider: '%env(REDIS_URL)%'

However, when I deploy this setup on Platform.sh, I encounter an error stating that the REDIS_URL environment variable cannot be found. As I understand it, this environment variable isn't provided directly by Platform.sh but needs to be extracted from the PLATFORM_RELATIONSHIPS base64-encoded JSON variable.

The interesting part is that when the application is running, everything works fine and the REDIS_URL is correctly set. The issue appears during the build phase when the symfony-build script is run as part of the build hook in my .platform.app.yaml file:

hooks:
  build: |
    set -x -e
    curl -fs https://get.symfony.com/cloud/configurator | bash
    NODE_VERSION=18 symfony-build

The symfony-build script seems to clear the cache during the build phase, which requires access to Redis. However, at this stage, the REDIS_URL variable isn't available yet, causing the build to fail.

I'm wondering if there's a way to prevent the symfony-build script from attempting to clear the cache during the build phase, or if there's a recommended way to handle such a scenario. Alternatively, if this behavior is considered a bug, I wanted to bring it to your attention.

Any advice or guidance on this matter would be greatly appreciated.

Thank you in advance for your help and time.

Best regards,
Michael