Source code for mmengine.registry.registry
# Copyright (c) OpenMMLab. All rights reserved.
import inspect
import logging
import sys
from collections.abc import Callable
from contextlib import contextmanager
from importlib import import_module
from typing import Any, Dict, Generator, List, Optional, Tuple, Type, Union
from mmengine.config.utils import PKG2PROJECT
from mmengine.utils import is_seq_of
from .default_scope import DefaultScope
[docs]class Registry:
"""A registry to map strings to classes or functions.
Registered object could be built from registry. Meanwhile, registered
functions could be called from registry.
Args:
name (str): Registry name.
build_func (callable, optional): A function to construct instance
from Registry. :func:`build_from_cfg` is used if neither ``parent``
or ``build_func`` is specified. If ``parent`` is specified and
``build_func`` is not given, ``build_func`` will be inherited
from ``parent``. Defaults to None.
parent (:obj:`Registry`, optional): Parent registry. The class
registered in children registry could be built from parent.
Defaults to None.
scope (str, optional): The scope of registry. It is the key to search
for children registry. If not specified, scope will be the name of
the package where class is defined, e.g. mmdet, mmcls, mmseg.
Defaults to None.
Examples:
>>> # define a registry
>>> MODELS = Registry('models')
>>> # registry the `ResNet` to `MODELS`
>>> @MODELS.register_module()
>>> class ResNet:
>>> pass
>>> # build model from `MODELS`
>>> resnet = MODELS.build(dict(type='ResNet'))
>>> @MODELS.register_module()
>>> def resnet50():
>>> pass
>>> resnet = MODELS.build(dict(type='resnet50'))
>>> # hierarchical registry
>>> DETECTORS = Registry('detectors', parent=MODELS, scope='det')
>>> @DETECTORS.register_module()
>>> class FasterRCNN:
>>> pass
>>> fasterrcnn = DETECTORS.build(dict(type='FasterRCNN'))
More advanced usages can be found at
https://mmengine.readthedocs.io/en/latest/tutorials/registry.html.
"""
def __init__(self,
name: str,
build_func: Optional[Callable] = None,
parent: Optional['Registry'] = None,
scope: Optional[str] = None):
from .build_functions import build_from_cfg
self._name = name
self._module_dict: Dict[str, Type] = dict()
self._children: Dict[str, 'Registry'] = dict()
if scope is not None:
assert isinstance(scope, str)
self._scope = scope
else:
self._scope = self.infer_scope()
# See https://mypy.readthedocs.io/en/stable/common_issues.html#
# variables-vs-type-aliases for the use
self.parent: Optional['Registry']
if parent is not None:
assert isinstance(parent, Registry)
parent._add_child(self)
self.parent = parent
else:
self.parent = None
# self.build_func will be set with the following priority:
# 1. build_func
# 2. parent.build_func
# 3. build_from_cfg
self.build_func: Callable
if build_func is None:
if self.parent is not None:
self.build_func = self.parent.build_func
else:
self.build_func = build_from_cfg
else:
self.build_func = build_func
def __len__(self):
return len(self._module_dict)
def __contains__(self, key):
return self.get(key) is not None
def __repr__(self):
format_str = self.__class__.__name__ + \
f'(name={self._name}, ' \
f'items={self._module_dict})'
return format_str
[docs] @staticmethod
def infer_scope() -> str:
"""Infer the scope of registry.
The name of the package where registry is defined will be returned.
Returns:
str: The inferred scope name.
Examples:
>>> # in mmdet/models/backbone/resnet.py
>>> MODELS = Registry('models')
>>> @MODELS.register_module()
>>> class ResNet:
>>> pass
>>> # The scope of ``ResNet`` will be ``mmdet``.
"""
# `sys._getframe` returns the frame object that many calls below the
# top of the stack. The call stack for `infer_scope` can be listed as
# follow:
# frame-0: `infer_scope` itself
# frame-1: `__init__` of `Registry` which calls the `infer_scope`
# frame-2: Where the `Registry(...)` is called
filename = inspect.getmodule(sys._getframe(2)).__name__ # type: ignore
split_filename = filename.split('.')
return split_filename[0]
[docs] @staticmethod
def split_scope_key(key: str) -> Tuple[Optional[str], str]:
"""Split scope and key.
The first scope will be split from key.
Return:
tuple[str | None, str]: The former element is the first scope of
the key, which can be ``None``. The latter is the remaining key.
Examples:
>>> Registry.split_scope_key('mmdet.ResNet')
'mmdet', 'ResNet'
>>> Registry.split_scope_key('ResNet')
None, 'ResNet'
"""
split_index = key.find('.')
if split_index != -1:
return key[:split_index], key[split_index + 1:]
else:
return None, key
@property
def name(self):
return self._name
@property
def scope(self):
return self._scope
@property
def module_dict(self):
return self._module_dict
@property
def children(self):
return self._children
@property
def root(self):
return self._get_root_registry()
[docs] @contextmanager
def switch_scope_and_registry(self, scope: str) -> Generator:
"""Temporarily switch default scope to the target scope, and get the
corresponding registry.
If the registry of the corresponding scope exists, yield the
registry, otherwise yield the current itself.
Args:
scope (str): The target scope.
Examples:
>>> from mmengine.registry import Registry, DefaultScope, MODELS
>>> import time
>>> # External Registry
>>> MMDET_MODELS = Registry('mmdet_model', scope='mmdet',
>>> parent=MODELS)
>>> MMCLS_MODELS = Registry('mmcls_model', scope='mmcls',
>>> parent=MODELS)
>>> # Local Registry
>>> CUSTOM_MODELS = Registry('custom_model', scope='custom',
>>> parent=MODELS)
>>>
>>> # Initiate DefaultScope
>>> DefaultScope.get_instance(f'scope_{time.time()}',
>>> scope_name='custom')
>>> # Check default scope
>>> DefaultScope.get_current_instance().scope_name
custom
>>> # Switch to mmcls scope and get `MMCLS_MODELS` registry.
>>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as registry:
>>> DefaultScope.get_current_instance().scope_name
mmcls
>>> registry.scope
mmcls
>>> # Nested switch scope
>>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmdet') as mmdet_registry:
>>> DefaultScope.get_current_instance().scope_name
mmdet
>>> mmdet_registry.scope
mmdet
>>> with CUSTOM_MODELS.switch_scope_and_registry(scope='mmcls') as mmcls_registry:
>>> DefaultScope.get_current_instance().scope_name
mmcls
>>> mmcls_registry.scope
mmcls
>>>
>>> # Check switch back to original scope.
>>> DefaultScope.get_current_instance().scope_name
custom
""" # noqa: E501
from ..logging import print_log
# Switch to the given scope temporarily. If the corresponding registry
# can be found in root registry, return the registry under the scope,
# otherwise return the registry itself.
with DefaultScope.overwrite_default_scope(scope):
# Get the global default scope
default_scope = DefaultScope.get_current_instance()
# Get registry by scope
if default_scope is not None:
scope_name = default_scope.scope_name
if scope_name in PKG2PROJECT:
try:
module = import_module(f'{scope_name}.utils')
module.register_all_modules() # type: ignore
except ImportError as e:
raise e
root = self._get_root_registry()
registry = root._search_child(scope_name)
if registry is None:
# if `default_scope` can not be found, fallback to argument
# `registry`
print_log(
f'Failed to search registry with scope "{scope_name}" '
f'in the "{root.name}" registry tree. '
f'As a workaround, the current "{self.name}" registry '
f'in "{self.scope}" is used to build instance. This '
'may cause unexpected failure when running the built '
f'modules. Please check whether "{scope_name}" is a '
'correct scope, or whether the registry is '
'initialized.',
logger='current',
level=logging.WARNING)
registry = self
# If there is no built default scope, just return current registry.
else:
registry = self
yield registry
def _get_root_registry(self) -> 'Registry':
"""Return the root registry."""
root = self
while root.parent is not None:
root = root.parent
return root
[docs] def get(self, key: str) -> Optional[Type]:
"""Get the registry record.
The method will first parse :attr:`key` and check whether it contains
a scope name. The logic to search for :attr:`key`:
- ``key`` does not contain a scope name, i.e., it is purely a module
name like "ResNet": :meth:`get` will search for ``ResNet`` from the
current registry to its parent or ancestors until finding it.
- ``key`` contains a scope name and it is equal to the scope of the
current registry (e.g., "mmcls"), e.g., "mmcls.ResNet": :meth:`get`
will only search for ``ResNet`` in the current registry.
- ``key`` contains a scope name and it is not equal to the scope of
the current registry (e.g., "mmdet"), e.g., "mmcls.FCNet": If the
scope exists in its children, :meth:`get` will get "FCNet" from
them. If not, :meth:`get` will first get the root registry and root
registry call its own :meth:`get` method.
Args:
key (str): Name of the registered item, e.g., the class name in
string format.
Returns:
Type or None: Return the corresponding class if ``key`` exists,
otherwise return None.
Examples:
>>> # define a registry
>>> MODELS = Registry('models')
>>> # register `ResNet` to `MODELS`
>>> @MODELS.register_module()
>>> class ResNet:
>>> pass
>>> resnet_cls = MODELS.get('ResNet')
>>> # hierarchical registry
>>> DETECTORS = Registry('detector', parent=MODELS, scope='det')
>>> # `ResNet` does not exist in `DETECTORS` but `get` method
>>> # will try to search from its parenet or ancestors
>>> resnet_cls = DETECTORS.get('ResNet')
>>> CLASSIFIER = Registry('classifier', parent=MODELS, scope='cls')
>>> @CLASSIFIER.register_module()
>>> class MobileNet:
>>> pass
>>> # `get` from its sibling registries
>>> mobilenet_cls = DETECTORS.get('cls.MobileNet')
"""
# Avoid circular import
from ..logging import print_log
scope, real_key = self.split_scope_key(key)
obj_cls = None
registry_name = self.name
scope_name = self.scope
if scope is None or scope == self._scope:
# get from self
if real_key in self._module_dict:
obj_cls = self._module_dict[real_key]
elif scope is None:
# try to get the target from its parent or ancestors
parent = self.parent
while parent is not None:
if real_key in parent._module_dict:
obj_cls = parent._module_dict[real_key]
registry_name = parent.name
scope_name = parent.scope
break
parent = parent.parent
else:
# get from self._children
if scope in self._children:
obj_cls = self._children[scope].get(real_key)
registry_name = self._children[scope].name
scope_name = scope
else:
root = self._get_root_registry()
if scope != root._scope and scope not in root._children:
# If not skip directly, `root.get(key)` will recursively
# call itself until RecursionError is thrown.
pass
else:
obj_cls = root.get(key)
if obj_cls is not None:
print_log(
f'Get class `{obj_cls.__name__}` from "{registry_name}"'
f' registry in "{scope_name}"',
logger='current',
level=logging.DEBUG)
return obj_cls
def _search_child(self, scope: str) -> Optional['Registry']:
"""Depth-first search for the corresponding registry in its children.
Note that the method only search for the corresponding registry from
the current registry. Therefore, if we want to search from the root
registry, :meth:`_get_root_registry` should be called to get the
root registry first.
Args:
scope (str): The scope name used for searching for its
corresponding registry.
Returns:
Registry or None: Return the corresponding registry if ``scope``
exists, otherwise return None.
"""
if self._scope == scope:
return self
for child in self._children.values():
registry = child._search_child(scope)
if registry is not None:
return registry
return None
[docs] def build(self, cfg: dict, *args, **kwargs) -> Any:
"""Build an instance.
Build an instance by calling :attr:`build_func`.
Args:
cfg (dict): Config dict needs to be built.
Returns:
Any: The constructed object.
Examples:
>>> from mmengine import Registry
>>> MODELS = Registry('models')
>>> @MODELS.register_module()
>>> class ResNet:
>>> def __init__(self, depth, stages=4):
>>> self.depth = depth
>>> self.stages = stages
>>> cfg = dict(type='ResNet', depth=50)
>>> model = MODELS.build(cfg)
"""
return self.build_func(cfg, *args, **kwargs, registry=self)
def _add_child(self, registry: 'Registry') -> None:
"""Add a child for a registry.
Args:
registry (:obj:`Registry`): The ``registry`` will be added as a
child of the ``self``.
"""
assert isinstance(registry, Registry)
assert registry.scope is not None
assert registry.scope not in self.children, \
f'scope {registry.scope} exists in {self.name} registry'
self.children[registry.scope] = registry
def _register_module(self,
module: Type,
module_name: Optional[Union[str, List[str]]] = None,
force: bool = False) -> None:
"""Register a module.
Args:
module (type): Module class or function to be registered.
module_name (str or list of str, optional): The module name to be
registered. If not specified, the class name will be used.
Defaults to None.
force (bool): Whether to override an existing class with the same
name. Defaults to False.
"""
if not inspect.isclass(module) and not inspect.isfunction(module):
raise TypeError('module must be a class or a function, '
f'but got {type(module)}')
if module_name is None:
module_name = module.__name__
if isinstance(module_name, str):
module_name = [module_name]
for name in module_name:
if not force and name in self._module_dict:
existed_module = self.module_dict[name]
raise KeyError(f'{name} is already registered in {self.name} '
f'at {existed_module.__module__}')
self._module_dict[name] = module
[docs] def register_module(
self,
name: Optional[Union[str, List[str]]] = None,
force: bool = False,
module: Optional[Type] = None) -> Union[type, Callable]:
"""Register a module.
A record will be added to ``self._module_dict``, whose key is the class
name or the specified name, and value is the class itself.
It can be used as a decorator or a normal function.
Args:
name (str or list of str, optional): The module name to be
registered. If not specified, the class name will be used.
force (bool): Whether to override an existing class with the same
name. Default to False.
module (type, optional): Module class or function to be registered.
Defaults to None.
Examples:
>>> backbones = Registry('backbone')
>>> # as a decorator
>>> @backbones.register_module()
>>> class ResNet:
>>> pass
>>> backbones = Registry('backbone')
>>> @backbones.register_module(name='mnet')
>>> class MobileNet:
>>> pass
>>> # as a normal function
>>> class ResNet:
>>> pass
>>> backbones.register_module(module=ResNet)
"""
if not isinstance(force, bool):
raise TypeError(f'force must be a boolean, but got {type(force)}')
# raise the error ahead of time
if not (name is None or isinstance(name, str) or is_seq_of(name, str)):
raise TypeError(
'name must be None, an instance of str, or a sequence of str, '
f'but got {type(name)}')
# use it as a normal method: x.register_module(module=SomeClass)
if module is not None:
self._register_module(module=module, module_name=name, force=force)
return module
# use it as a decorator: @x.register_module()
def _register(module):
self._register_module(module=module, module_name=name, force=force)
return module
return _register