feat: support subPath for library

[ilazycat]

It will be handy if we can set subPath in library config so we don't have to create and manage separate pv for library/machine-learning-models/postgre/redis.

It allows us to do something like this:

image:
  tag: v1.113.0

immich:
  metrics:
    enabled: false
  persistence:
    library:
      existingClaim: immich
      subPath: data

machine-learning:
  persistence:
    cache:
      enabled: true
      type: null # Have to set this to null otherwise emptyDir will be used.
      path: /cache
      existingClaim: immich
      subPath: ml-model-cache

postgresql:
  enabled: true
  primary:
    persistence:
      existingClaim: immich
      subPath: postgresql

redis:
  enabled: true
  auth:
    enabled: false
  master:
    persistence:
      existingClaim: immich
      subPath: redis

[bo0tzz]

Thanks for the PR! Putting multiple not-quite-related things into the same PVC feels like an antipattern to me, so I'd rather not add a specific option for that. However, if you want to contribute a change that makes it possible to set any of the upstream values in the library persistence block in a generic way, that would be welcome.

[ilazycat]

@bo0tzz I think you are right. I updated the code, using toYaml function to make it possible to set any of the values under persistence.library.

[ilazycat]

After some quick testing I found it possible to use hostPath as library.

  persistence:
    library:
      existingClaim: immich
      type: hostPath
      hostPath: /data/
      subPath: immich

However existingClaim is still required since there's some checking done in templates/checks.yaml

[bo0tzz]

Intuitively the toYaml approach doesn't feel correct to me, but I'm not familiar enough with helm to suggest anything better 🤔

[ilazycat]

Actually I've tried several other methods. They are either not working or didn't get along well with bjw-s' common chart library, not giving the desired output. toYaml is the best working method in my test. Yet I'm not a helm expert as well so I'll let you decide.