Build container from schema

[torotil]

I’ve discovered this project while looking for Python dependency injection solutions. So far it seems to be the most promising one.

One thing I’m looking for is to specify dependencies in a serializable format. Something that could be read or written to easily to a YAML file. Is this possilbe with this package? If not: What would be the most likely way to implement it?

[rmk135]

Hi @torotil , take a look at https://python-dependency-injector.ets-labs.org/providers/configuration.html#loading-from-a-yaml-file

[torotil]

Hi @torotil , take a look at https://python-dependency-injector.ets-labs.org/providers/configuration.html#loading-from-a-yaml-file

Thanks. Seems I have put the question in a misleading way. What I meant with “container config” is the specs of how to instantiate services (providers), not some config values. Is there a way to put those into YAML as well?

[rmk135]

Got it. There is no way to do it out of the box. Take a look at DynamicContainer example here: https://python-dependency-injector.ets-labs.org/containers/dynamic.html

[rmk135]

@torotil I thought about your question and don't see anything that prevents adding this feature in the framework. I'll convert this into into a feature. Let me know if you'd like to participate as early adopter.

[mysticfall]

I also have the same requirements as desribed by the issue and I'd be more than happy to be able to test the feature as an early adopter when it becomes available.

By the way, I also considered using DynamicContainer but I decided against it once I learned that it does not support wiring like its declarative counterpart.

I think it'd be ideal if there's a way to construct a container from Configuration, and possibly support doing so in a cascading manner (e.g. constructing a container from a given value of a Configuration, then allow the new container to construct its child containers in the same manner from a chosen subtree of its parent configuration tree, and so on).

[rmk135]

@mysticfall , got it, sounds good. The feature is in the backlog. Will begin working on it as done with earlier backlog items.

[rmk135]

Started working on this feature. Here is a sample schema for single container example:

version: "1"

providers:
  config:
    provider: Configuration

  logging:
    provider: Resource
    provides: logging.config.fileConfig
    kwargs:
      fname: ./example/logging.ini

  database_client:
    provider: Singleton
    provides: sqlite3.connect
    args:
      - config.database.dsn

  s3_client:
    provider: Singleton
    provides: boto3.client
    kwargs:
      service_name: s3
      aws_access_key_id: config.aws.access_key_id
      aws_secret_access_key: config.aws.secret_access_key

  user_service:
    provider: Factory
    provides: example.services.UserService
    kwargs:
      db: database_client

  auth_service:
    provider: Factory
    provides: example.services.AuthService
    kwargs:
      db: database_client
      token_ttl: config.auth.token_ttl.as_int()

  photo_service:
    provider: Factory
    provides: example.services.PhotoService
    kwargs:
      db: database_client
      s3: s3_client

Appreciate you feedback @torotil @mysticfall

[torotil]

Awesome, thanks! I’ll try to look into it soon.