Coastline

Registry

The Registry provides a singleton-based mechanism for managing registered configuration classes.

Overview

from coastline import Registry

Singleton Pattern

The Registry uses a singleton pattern to ensure only one registry instance exists:

registry1 = Registry.get_instance()
registry2 = Registry.get_instance()

print(registry1 is registry2)  # True

Methods

get_instance()

Returns the singleton Registry instance.

registry = Registry.get_instance()

register(name, cls)

Registers a configuration class with a given name.

Parameters:

• name (str): The key to register the class under
• cls (type): The class to register

from coastline import Registry, config
from pydantic import BaseModel

registry = Registry.get_instance()

@config
class Database(BaseModel):
    host: str
    port: int

# Or register manually
registry.register("Database", Database)

get(name)

Retrieves a registered class by name.

Parameters:

• name (str): The key of the class to retrieve

Returns:

• The registered class, or None if not found

cls = registry.get("Database")
if cls:
    instance = cls(host="localhost", port=5432)

list()

Lists all registered configuration keys.

Returns:

• list[str]: List of all registered key names

keys = registry.list()
print(keys)  # ['Database', 'Cache', 'Settings']

clear()

Clears all registered configurations.

registry.clear()
print(registry.list())  # []

Usage with @config Decorator

The @config decorator uses the Registry internally:

from coastline import config, Registry

@config
class Database(BaseModel):
    host: str
    port: int

# Equivalent to:
# Registry.get_instance().register("Database", Database)

Programmatic Access

You can use the Registry directly for more control:

from coastline import Registry

registry = Registry.get_instance()

# Register classes manually
class Database(BaseModel):
    host: str
    port: int

registry.register("DB", Database)

# Later, get the class
cls = registry.get("DB")

Testing

The Registry can be cleared between tests:

import pytest
from coastline import Registry

@pytest.fixture(autouse=True)
def clean_registry():
    Registry.get_instance().clear()
    yield
    Registry.get_instance().clear()

Best Practices

1. Use @config decorator for most cases - it handles registration automatically
2. Use Registry directly for dynamic class registration
3. Clear registry in tests to ensure test isolation
4. Use descriptive names to avoid conflicts