ExZarr.Storage.Registry (ExZarr v1.1.0)

Registry for managing storage backends.

The registry maintains a mapping of backend IDs to backend modules and provides functions for registering, querying, and using storage backends.

Built-in Backends

The following backends are registered by default:

:memory - In-memory storage (fast, non-persistent)
:filesystem - Local filesystem storage
:zip - Zip archive storage

Registering Custom Backends

Via Configuration

Add to config/config.exs:

config :ex_zarr, :custom_storage_backends, [
  MyApp.S3Storage,
  MyApp.DatabaseStorage
]

Programmatically

ExZarr.Storage.Registry.register(MyApp.S3Storage)

At Application Start

defmodule MyApp.Application do
  use Application

  def start(_type, _args) do
    # Register custom storage backends
    ExZarr.Storage.Registry.register(MyApp.S3Storage)

    # ... rest of supervision tree
  end
end

Querying Backends

# Get a backend module
{:ok, module} = ExZarr.Storage.Registry.get(:s3)

# List all registered backend IDs
ids = ExZarr.Storage.Registry.list()

# Get backend information
{:ok, info} = ExZarr.Storage.Registry.info(:s3)

Summary

Types

backend_id()

backend_module()

registry_state()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

get(backend_id)

Gets a storage backend module by ID.

info(backend_id)

Gets information about a storage backend.

list()

Lists all registered backend IDs.

Registers a custom storage backend module.

start_link(opts \\ [])

Starts the storage backend registry.

unregister(backend_id)

Unregisters a storage backend by ID.

Types

backend_id()

@type backend_id() :: atom()

backend_module()

@type backend_module() :: module()

registry_state()

@type registry_state() :: %{
  backends: %{required(backend_id()) => backend_module()},
  built_in: [backend_id()]
}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

get(backend_id)

@spec get(backend_id()) :: {:ok, backend_module()} | {:error, :not_found}

Gets a storage backend module by ID.

Examples

iex> ExZarr.Storage.Registry.get(:filesystem)
{:ok, ExZarr.Storage.Backend.Filesystem}

iex> ExZarr.Storage.Registry.get(:nonexistent)
{:error, :not_found}

Returns

{:ok, module()} - Backend found
{:error, :not_found} - Backend not registered

info(backend_id)

@spec info(backend_id()) :: {:ok, map()} | {:error, :not_found}

Gets information about a storage backend.

Returns backend metadata if the module provides a backend_info/0 callback, otherwise returns basic information.

Examples

iex> ExZarr.Storage.Registry.info(:filesystem)
{:ok, %{
  id: :filesystem,
  module: ExZarr.Storage.Backend.Filesystem,
  description: "Local filesystem storage"
}}

Returns

{:ok, map()} - Backend information
{:error, :not_found} - Backend not registered

list()

@spec list() :: [backend_id()]

Lists all registered backend IDs.

Examples

iex> ExZarr.Storage.Registry.list()
[:memory, :filesystem, :zip, :s3, :database]

register(backend_module, opts \\ [])

@spec register(
  backend_module(),
  keyword()
) :: :ok | {:error, term()}

Registers a custom storage backend module.

The module must implement the Backend behavior.

Options

:force - If true, overwrites existing backend with same ID (default: false)

Examples

iex> ExZarr.Storage.Registry.register(MyApp.S3Storage)
:ok

iex> ExZarr.Storage.Registry.register(MyBackend, force: true)
:ok

Returns

:ok - Backend registered successfully
{:error, :already_registered} - Backend ID already in use (unless force: true)
{:error, :invalid_backend} - Module doesn't implement Backend behavior

start_link(opts \\ [])

@spec start_link(keyword()) :: GenServer.on_start()

Starts the storage backend registry.

This is typically called automatically by the application supervision tree.

unregister(backend_id)

@spec unregister(backend_id()) :: :ok | {:error, term()}

Unregisters a storage backend by ID.

Built-in backends cannot be unregistered.

Examples

iex> ExZarr.Storage.Registry.unregister(:my_backend)
:ok

iex> ExZarr.Storage.Registry.unregister(:filesystem)
{:error, :cannot_unregister_builtin}

Returns

:ok - Backend unregistered successfully
{:error, :not_found} - Backend not registered
{:error, :cannot_unregister_builtin} - Cannot unregister built-in backend