The registry system has two layers: RegistryGroup (one per domain) and ModuleRegistry (the global singleton that holds all groups).

RegistryGroup

A RegistryGroup is a named, namespaced store of module_path → config mappings.

DATASETS = RegistryGroup(name="DATASETS", package="atria_datasets")

Registration — a @DATASETS.register("cifar10/standard") decorator: 1. Calls the config's __init__ to get default values. 2. Hashes the config. 3. Stores {"hash": ..., "config": ...} at the path "cifar10/standard" in the in-memory store.

Lookup — DATASETS.load_module_config("cifar10/standard"): 1. Walks the path in the in-memory store (falling back to SQLite if not found). 2. Calls Hydra instantiate on the stored config dict to reconstruct the ModuleConfig. 3. Returns the live config object ready for .build().

Hierarchical paths — paths like "cifar10/standard" or "timm/resnet50/classification" form a tree in the store, allowing listing all variants of a dataset or model family.

Persistence — RegistryGroup.dump() writes the in-memory store to a SQLite database (registry.db) next to the package. On the next process start, RegistryGroup.load() reads from disk. This means the CLI can call load_dataset_config("cifar10/standard") without importing every dataset module.

ModuleRegistry

ModuleRegistry is a process-wide singleton that collects all RegistryGroup instances across Atria packages:

module_registry = ModuleRegistry()
module_registry.add_registry_group("DATASETS", DATASETS)
module_registry.add_registry_group("MODEL_PIPELINES", MODEL_PIPELINES)

Groups are accessible by attribute or by item:

module_registry.DATASETS           # RegistryGroup
module_registry["MODEL_PIPELINES"] # same

Named registry groups in Atria

Comparison to HuggingFace AutoModel

HuggingFace's AutoModel.from_pretrained("bert-base") pattern applies only to models. Atria's registry applies the same lookup-by-name pattern uniformly to every component in the framework — datasets, transforms, metrics, explainers — enabling fully config-driven pipelines where no component is hardcoded.