"""
Define a class to hold configurations.
Borrows and merges stuff from YACS, fvcore, and detectron2
https://github.com/rbgirshick/yacs
https://github.com/facebookresearch/fvcore/
https://github.com/facebookresearch/detectron2/
"""
import copy
import importlib.util
import io
import logging
import os
from typing import Optional
import yaml
from ast import literal_eval
# File exts for yaml
_YAML_EXTS = {"", ".yml", ".yaml"}
# File exts for python
_PY_EXTS = {".py"}
# CfgNodes can only contain a limited set of valid types
_VALID_TYPES = {tuple, list, str, int, float, bool}
# Valid file object types
_FILE_TYPES = (io.IOBase,)
# Logger
logger = logging.getLogger(__name__)
[docs]class CfgNode(dict):
r"""CfgNode is a `node` in the configuration `tree`. It's a simple wrapper around a `dict` and supports access to
`attributes` via `keys`.
"""
IMMUTABLE = "__immutable__"
DEPRECATED_KEYS = "__deprecated_keys__"
RENAMED_KEYS = "__renamed_keys__"
NEW_ALLOWED = "__new_allowed__"
def __init__(
self,
init_dict: Optional[dict] = None,
key_list: Optional[list] = None,
new_allowed: Optional[bool] = False,
):
r"""
Args:
init_dict (dict): A dictionary to initialize the `CfgNode`.
key_list (list[str]): A list of names that index this `CfgNode` from the root. Currently, only used for
logging.
new_allowed (bool): Whether adding a new key is allowed when merging with other `CfgNode` objects.
"""
# Recursively convert nested dictionaries in `init_dict` to config tree.
init_dict = {} if init_dict is None else init_dict
key_list = [] if key_list is None else key_list
init_dict = self._create_config_tree_from_dict(init_dict, key_list)
super(CfgNode, self).__init__(init_dict)
# Control the immutability of the `CfgNode`.
self.__dict__[CfgNode.IMMUTABLE] = False
# Support for deprecated options.
# If you choose to remove support for an option in code, but don't want to change all of the config files
# (to allow for deprecated config files to run), you can add the full config key as a string to this set.
self.__dict__[CfgNode.DEPRECATED_KEYS] = set()
# Support for renamed options.
# If you rename an option, record the mapping from the old name to the new name in this dictionary. Optionally,
# if the type also changed, you can make this value a tuple that specifies two things: the renamed key, and the
# instructions to edit the config file.
self.__dict__[CfgNode.RENAMED_KEYS] = {
# 'EXAMPLE.OLD.KEY': 'EXAMPLE.NEW.KEY', # Dummy example
# 'EXAMPLE.OLD.KEY': ( # A more complex example
# 'EXAMPLE.NEW.KEY',
# "Also convert to a tuple, eg. 'foo' -> ('foo', ) or "
# + "'foo.bar' -> ('foo', 'bar')"
# ),
}
# Allow new attributes after initialization.
self.__dict__[CfgNode.NEW_ALLOWED] = new_allowed
@classmethod
def _create_config_tree_from_dict(cls, init_dict: dict, key_list: list):
r"""Create a configuration tree using the input dict. Any dict-like objects inside `init_dict` will be treated
as new `CfgNode` objects.
Args:
init_dict (dict): Input dictionary, to create config tree from.
key_list (list): A list of names that index this `CfgNode` from the root. Currently only used for logging.
"""
d = copy.deepcopy(init_dict)
for k, v in d.items():
if isinstance(v, dict):
# Convert dictionary to CfgNode
d[k] = cls(v, key_list=key_list + [k])
else:
# Check for valid leaf type or nested CfgNode
_assert_with_logging(
_valid_type(v, allow_cfg_node=False),
"Key {} with value {} is not a valid type; valid types: {}".format(
".".join(key_list + [k]), type(v), _VALID_TYPES
),
)
return d
def __getattr__(self, name: str):
if name in self:
return self[name]
else:
raise AttributeError(name)
def __setattr__(self, name: str, value):
if self.is_frozen():
raise AttributeError(
"Attempted to set {} to {}, but CfgNode is immutable".format(
name, value
)
)
_assert_with_logging(
name not in self.__dict__,
"Invalid attempt to modify internal CfgNode state: {}".format(name),
)
_assert_with_logging(
_valid_type(value, allow_cfg_node=True),
"Invalid type {} for key {}; valid types = {}".format(
type(value), name, _VALID_TYPES
),
)
self[name] = value
def __str__(self):
def _indent(s_, num_spaces):
s = s_.split("\n")
if len(s) == 1:
return s_
first = s.pop(0)
s = [(num_spaces * " ") + line for line in s]
s = "\n".join(s)
s = first + "\n" + s
return s
r = ""
s = []
for k, v in sorted(self.items()):
separator = "\n" if isinstance(v, CfgNode) else " "
attr_str = "{}:{}{}".format(str(k), separator, str(v))
attr_str = _indent(attr_str, 2)
s.append(attr_str)
r += "\n".join(s)
return r
def __repr__(self):
return "{}({})".format(self.__class__.__name__, super(CfgNode, self).__repr__())
[docs] def dump(self, **kwargs):
r"""Dump CfgNode to a string."""
def _convert_to_dict(cfg_node, key_list):
if not isinstance(cfg_node, CfgNode):
_assert_with_logging(
_valid_type(cfg_node),
"Key {} with value {} is not a valid type; valid types: {}".format(
".".join(key_list), type(cfg_node), _VALID_TYPES
),
)
return cfg_node
else:
cfg_dict = dict(cfg_node)
for k, v in cfg_dict.items():
cfg_dict[k] = _convert_to_dict(v, key_list + [k])
return cfg_dict
self_as_dict = _convert_to_dict(self, [])
return yaml.safe_dump(self_as_dict, **kwargs)
[docs] def merge_from_file(self, cfg_filename: str):
r"""Load a yaml config file and merge it with this CfgNode.
Args:
cfg_filename (str): Config file path.
"""
with open(cfg_filename, "r") as f:
cfg = self.load_cfg(f)
self.merge_from_other_cfg(cfg)
[docs] def merge_from_other_cfg(self, cfg_other):
r"""Merge `cfg_other` into the current `CfgNode`.
Args:
cfg_other
"""
_merge_a_into_b(cfg_other, self, self, [])
[docs] def merge_from_list(self, cfg_list: list):
r"""Merge config (keys, values) in a list (eg. from commandline) into this `CfgNode`.
Eg. `cfg_list = ['FOO.BAR', 0.5]`.
"""
_assert_with_logging(
len(cfg_list) % 2 == 0,
"Override list has odd lengths: {}; it must be a list of pairs".format(
cfg_list
),
)
root = self
for full_key, v in zip(cfg_list[0::2], cfg_list[1::2]):
if root.key_is_deprecated(full_key):
continue
if root.key_is_renamed(full_key):
root.raise_key_rename_error(full_key)
key_list = full_key.split(".")
d = self
for subkey in key_list[:-1]:
_assert_with_logging(
subkey in d, "Non-existent key: {}".format(full_key)
)
d = d[subkey]
subkey = key_list[-1]
_assert_with_logging(subkey in d, "Non-existent key: {}".format(full_key))
value = self._decode_cfg_value(v)
value = _check_and_coerce_cfg_value_type(value, d[subkey], subkey, full_key)
d[subkey] = value
[docs] def freeze(self):
r"""Make this `CfgNode` and all of its children immutable. """
self._immutable(True)
[docs] def defrost(self):
r"""Make this `CfgNode` and all of its children mutable. """
self._immutable(False)
[docs] def is_frozen(self):
r"""Return mutability. """
return self.__dict__[CfgNode.IMMUTABLE]
def _immutable(self, is_immutable: bool):
r"""Set mutability and recursively apply to all nested `CfgNode` objects.
Args:
is_immutable (bool): Whether or not the `CfgNode` and its children are immutable.
"""
self.__dict__[CfgNode.IMMUTABLE] = is_immutable
# Recursively propagate state to all children.
for v in self.__dict__.values():
if isinstance(v, CfgNode):
v._immutable(is_immutable)
for v in self.values():
if isinstance(v, CfgNode):
v._immutable(is_immutable)
[docs] def clone(self):
r"""Recursively copy this `CfgNode`. """
return copy.deepcopy(self)
[docs] def register_deprecated_key(self, key: str):
r"""Register key (eg. `FOO.BAR`) a deprecated option. When merging deprecated keys, a warning is generated and
the key is ignored.
"""
_assert_with_logging(
key not in self.__dict__[CfgNode.DEPRECATED_KEYS],
"key {} is already registered as a deprecated key".format(key),
)
self.__dict__[CfgNode.DEPRECATED_KEYS].add(key)
[docs] def register_renamed_key(
self, old_name: str, new_name: str, message: Optional[str] = None
):
r"""Register a key as having been renamed from `old_name` to `new_name`. When merging a renamed key, an
exception is thrown alerting the user to the fact that the key has been renamed.
"""
_assert_with_logging(
old_name not in self.__dict__[CfgNode.RENAMED_KEYS],
"key {} is already registered as a renamed cfg key".format(old_name),
)
value = new_name
if message:
value = (new_name, message)
self.__dict__[CfgNode.RENAMED_KEYS][old_name] = value
[docs] def key_is_deprecated(self, full_key: str):
r"""Test if a key is deprecated. """
if full_key in self.__dict__[CfgNode.DEPRECATED_KEYS]:
logger.warning("deprecated config key (ignoring): {}".format(full_key))
return True
return False
[docs] def key_is_renamed(self, full_key: str):
r"""Test if a key is renamed. """
return full_key in self.__dict__[CfgNode.RENAMED_KEYS]
def raise_key_rename_error(self, full_key: str):
new_key = self.__dict__[CfgNode.RENAMED_KEYS][full_key]
if isinstance(new_key, tuple):
msg = " Note: " + new_key[1]
new_key = new_key[0]
else:
msg = ""
raise KeyError(
"Key {} was renamed to {}; please update your config.{}".format(
full_key, new_key, msg
)
)
def is_new_allowed(self):
return self.__dict__[CfgNode.NEW_ALLOWED]
[docs] @classmethod
def load_cfg(cls, cfg_file_obj_or_str):
r"""Load a configuration into the `CfgNode`.
Args:
cfg_file_obj_or_str (str or cfg compatible object): Supports loading from:
- A file object backed by a YAML file.
- A file object backed by a Python source file that exports an sttribute "cfg" (dict or `CfgNode`).
- A string that can be parsed as valid YAML.
"""
_assert_with_logging(
isinstance(cfg_file_obj_or_str, _FILE_TYPES + (str,)),
"Expected first argument to be of type {} or {}, but got {}".format(
_FILE_TYPES, str, type(cfg_file_obj_or_str)
),
)
if isinstance(cfg_file_obj_or_str, str):
return cls._load_cfg_from_yaml_str(cfg_file_obj_or_str)
elif isinstance(cfg_file_obj_or_str, _FILE_TYPES):
return cls._load_cfg_from_file(cfg_file_obj_or_str)
else:
raise NotImplementedError("Impossible to reach here (unless there's a bug)")
@classmethod
def _load_cfg_from_file(cls, file_obj):
r"""Load a config from a YAML file or a Python source file. """
_, file_ext = os.path.splitext(file_obj.name)
if file_ext in _YAML_EXTS:
return cls._load_cfg_from_yaml_str(file_obj.read())
elif file_ext in _PY_EXTS:
return cls._load_cfg_py_source(file_obj.name)
else:
raise Exception(
"Attempt to load from an unsupported filetype {}; only {} supported".format(
file_ext, _YAML_EXTS.union(_PY_EXTS)
)
)
@classmethod
def _load_cfg_from_yaml_str(cls, str_obj):
r"""Load a config from a YAML string encoding. """
cfg_as_dict = yaml.safe_load(str_obj)
return cls(cfg_as_dict)
@classmethod
def _load_cfg_py_source(cls, filename):
r"""Load a config from a Python source file. """
module = _load_module_from_file("yacs.config.override", filename)
_assert_with_logging(
hasattr(module, "cfg"),
"Python module from file {} must export a 'cfg' attribute".format(filename),
)
VALID_ATTR_TYPES = {dict, CfgNode}
_assert_with_logging(
type(module.cfg) in VALID_ATTR_TYPES,
"Import module 'cfg' attribute must be in {} but is {}".format(
VALID_ATTR_TYPES, type(module.cfg)
),
)
return cls(module.cfg)
@classmethod
def _decode_cfg_value(cls, value):
r"""Decodes a raw config value (eg. from a yaml config file or commandline argument) into a Python object.
If `value` is a dict, it will be interpreted as a new `CfgNode`.
If `value` is a str, it will be evaluated as a literal.
Otherwise, it is returned as is.
"""
# Configs parsed from raw yaml will contain dictionary keys that need to be converted to `CfgNode` objects.
if isinstance(value, dict):
return cls(value)
# All remaining processing is only applied to strings.
if not isinstance(value, str):
return value
# Try to interpret `value` as a: string, number, tuple, list, dict, bool, or None
try:
value = literal_eval(value)
# The following two excepts allow `value` to pass through it when it represents a string.
# The type of `value` is always a string (before calling `literal_eval`), but sometimes it *represents* a
# string and other times a data structure, like a list. In the case that `value` represents a str, what we
# got back from the yaml parser is `foo` *without quotes* (so, not `"foo"`). `literal_eval` is ok with `"foo"`,
# but will raise a `ValueError` if given `foo`. In other cases, like paths (`val = 'foo/bar'`) `literal_eval`
# will raise a `SyntaxError`.
except ValueError:
pass
except SyntaxError:
pass
return value
# Keep this function in global scope, for backward compataibility.
load_cfg = CfgNode.load_cfg
def _valid_type(value, allow_cfg_node: Optional[bool] = False):
return (type(value) in _VALID_TYPES) or (
allow_cfg_node and isinstance(value, CfgNode)
)
def _merge_a_into_b(a: CfgNode, b: CfgNode, root: CfgNode, key_list: list):
r"""Merge `CfgNode` `a` into `CfgNode` `b`, clobbering the options in `b` wherever they are also specified in `a`."""
_assert_with_logging(
isinstance(a, CfgNode),
"`a` (cur type {}) must be an instance of {}".format(type(a), CfgNode),
)
_assert_with_logging(
isinstance(b, CfgNode),
"`b` (cur type {}) must be an instance of {}".format(type(b), CfgNode),
)
for k, v_ in a.items():
full_key = ".".join(key_list + [k])
v = copy.deepcopy(v_)
v = b._decode_cfg_value(v)
if k in b:
v = _check_and_coerce_cfg_value_type(v, b[k], k, full_key)
# Recursively merge dicts.
if isinstance(v, CfgNode):
try:
_merge_a_into_b(v, b[k], root, key_list + [k])
except BaseException:
raise
else:
b[k] = v
elif b.is_new_allowed():
b[k] = v
else:
if root.key_is_deprecated(full_key):
continue
elif root.key_is_renamed(full_key):
root.raise_key_rename_error(full_key)
else:
raise KeyError("Non-existent config key: {}".format(full_key))
def _check_and_coerce_cfg_value_type(replacement, original, key, full_key):
r"""Checks that `replacement`, which is intended to replace `original` is of the right type. The type is correct if
it matches exactly or is one of a few cases in which the type can easily be coerced.
"""
original_type = type(original)
replacement_type = type(replacement)
if replacement_type == original_type:
return replacement
# If replacement and original types match, cast replacement from `from_type` to `to_type`.
def _conditional_cast(from_type, to_type):
if replacement_type == from_type and original_type == to_type:
return True, to_type(replacement)
else:
return False, None
# Conditional casts.
# list <-> tuple
casts = [(tuple, list), (list, tuple)]
for (from_type, to_type) in casts:
converted, converted_value = _conditional_cast(from_type, to_type)
if converted:
return converted_value
raise ValueError(
"Type mismatch ({} vs. {} with values ({} vs. {}) for config key: {}".format(
original_type, replacement_type, original, replacement, full_key
)
)
def _assert_with_logging(cond, msg):
if not cond:
logger.debug(msg)
assert cond, msg
def _load_module_from_file(name, filename):
spec = importlib.util.spec_from_file_location(name, filename)
module = importlib.util.module_from_spec(spec)
spec.loader.exec_module(module)
return module