Dynamic Adapters

Volundr uses a dynamic adapter pattern for most infrastructure components. Config specifies what class to load and what arguments to pass. No factory functions, no match/case chains.

How It Works

1. Config specifies a fully-qualified class path in the adapter key.
2. Remaining keys under kwargs are passed as **kwargs to the constructor.
3. Some adapters accept injected ports (e.g., StoragePort, CredentialStorePort). These are wired automatically by the application at startup.
4. Sensitive kwargs can come from Kubernetes Secrets via secretKwargs (Helm) or secret_kwargs_env (config.yaml).

Import Mechanism

The container resolves the class at startup:

module_path, class_name = dotted_path.rsplit(".", 1)
module = importlib.import_module(module_path)
cls = getattr(module, class_name)
instance = cls(**kwargs)

No registration step. If the class exists on the Python path, it works.

Writing Your Own Adapter

1. Implement the relevant port interface (e.g., PodManager, CredentialStorePort).
2. Accept your config as constructor kwargs.
3. Use **_extra to ignore injected kwargs you don't need.
4. Set the adapter key in config to your class path.

from volundr.ports.credential_store import CredentialStorePort

class MyCredentialStore(CredentialStorePort):
    def __init__(self, api_url: str, api_key: str, **_extra):
        self._url = api_url
        self._key = api_key

    async def get_credential(self, user_id: str, name: str) -> str | None:
        ...

credentialStore:
  adapter: "mypackage.creds.MyCredentialStore"
  kwargs:
    api_url: "https://secrets.internal"
  secretKwargs:
    api_key:
      secretName: my-creds
      key: api-key

All Adapter-Driven Components

Component	Port	Default Adapter
Pod manager	PodManager	FluxPodManager
Identity	IdentityPort	AllowAllIdentityAdapter
Authorization	AuthorizationPort	AllowAllAuthorizationAdapter
Credential store	CredentialStorePort	MemoryCredentialStore
Secret injection	SecretInjectionPort	InMemorySecretInjectionAdapter
Storage	StoragePort	InMemoryStorageAdapter
Gateway	GatewayPort	InMemoryGatewayAdapter
Resource provider	ResourceProvider	StaticResourceProvider
Session contributors	SessionContributor	(10 default contributors)

Each component page in this section documents the available adapters and their configuration.