Import Strategy

grelmicro follows the Django/SQLAlchemy pattern: core API is re-exported from package __init__.py, backends are imported from their submodules.

Principle

Import from	Contains
Package (grelmicro.sync)	Primitives, protocols, errors, types (what every user needs)
Submodule (grelmicro.sync.redis)	Backend implementations (infrastructure-specific code)

Rationale

No unnecessary imports. Importing a primitive does not pull in backend client libraries. Users only pay for the backend they choose.

Explicit dependencies. A submodule import like from grelmicro.sync.redis import RedisSyncBackend makes the infrastructure dependency visible at the import site. Grepping for the submodule path finds every file that needs that backend.

Ecosystem convention. Django databases, SQLAlchemy dialects, and Celery brokers all follow this pattern. Backends are selected once in configuration, not scattered across business logic.