Source code for hyperpyyaml.core

"""This library gathers utilities for hyperpyyaml loading

 * Peter Plantinga 2020
 * Aku Rouhe 2020

import re
import ast
import yaml
import copy
import pydoc
import os.path
import inspect
import functools
import collections
import ruamel.yaml
import operator as op
from io import StringIO

# NOTE: Empty dict as default parameter is fine here since overrides are never
# modified
[docs]def load_hyperpyyaml( yaml_stream, overrides=None, overrides_must_match=True, ): r'''This function implements the HyperPyYAML syntax The purpose for this syntax is a compact, structured hyperparameter and function definition. This function implements a few extensions to the yaml syntax, listed below. **PyYAML complex tag shortcuts** Part of our clean structured hyperparameter interface is being able to specify python objects easily and cleanly. This is possible with native YAML using the following syntax: .. code-block:: yaml alignment_saver: !!python/object/new:speechbrain.data_io.TensorSaver kwargs: {save_dir: results/asr/ali} However, due to the extensive use within speechbrain yaml files, we have added a shortcut for this that has the following syntax: .. code-block:: yaml alignment_saver: !new:speechbrain.data_io.TensorSaver save_dir: results/asr/ali In this example, the alignment_saver will be an instance of the ``TensorSaver`` class, with ``'exp/asr/ali'`` passed to the ``__init__()`` method as a keyword argument. This is equivalent to: .. code-block:: python import speechbrain.data_io.data_io alignment_saver = speechbrain.data_io.TensorSaver( save_dir='exp/asr/ali' ) We have also implemented a few more shortcuts::: !!python/name: => !name: !!python/module: => !module: !!python/object/apply: => !apply: **References and copies** Allows internal references to any node in the file. Any node with tag ``!ref`` will create an object reference to the yaml object at the ``<key.subkey>`` location within the yaml itself, following reference chains. .. code-block:: yaml output_folder: results/asr alignment_saver: !new:speechbrain.data_io.TensorSaver save_dir: !ref <output_folder> Strings values are handled specially: references are substituted but the rest of the string is left in place, allowing filepaths to be easily extended: .. code-block:: yaml output_folder: results/asr alignment_saver: !new:speechbrain.data_io.TensorSaver save_dir: !ref <output_folder>/ali # results/asr/ali A more complex example for demonstration purposes: .. code-block:: yaml key1: {a: !new:object {arg1: 1}} key2: !ref <key1[a]> Here, ``key2`` will contain a reference to the ``a`` object, so changing ``a.arg1`` will also change ``key2.arg1``. If you need a deep copy of the object instead of a shallow reference, you can use a similar syntax with the tag ``!copy``. For example: .. code-block:: yaml key1: {a: !new:object {arg1: 1}} key2: !copy <key1[a]> These will also implement very basic arithmetic, so: .. code-block:: yaml key1: 1 key2: !ref <key1> + 3 # this is 4 **Tuples** One last minor enhancement is an implicit tuple resolver. Passing a string value of ``(3, 4)`` will be given a tag of ``!tuple`` which is then interpreted as a tuple. Arguments --------- yaml_stream : stream A file-like object or string from which to read. overrides : mapping or str A set of overrides for the values read from the stream. As yaml implements a nested structure, so can the overrides. See `speechbrain.utils.data_utils.recursive_update` overrides_must_match : bool Whether an error will be thrown when an override does not match a corresponding key in the yaml_stream. return_dict : bool Whether to return a dictionary rather than the default namespace. Returns ------- hparams : dict Reflects the structure of ``yaml_stream``. Example ------- >>> yaml_string = """ ... a: 3 ... thing: !new:collections.Counter ... b: !ref <a> ... """ >>> params = load_hyperpyyaml(yaml_string) >>> params["thing"] Counter({'b': 3}) ''' yaml_stream = resolve_references( yaml_stream, overrides, overrides_must_match ) # Parse flat tuples (no nesting of lists, dicts) yaml.Loader.add_constructor(tag="!tuple", constructor=_make_tuple) tuple_pattern = re.compile(r"^\(.*\)$") yaml.Loader.add_implicit_resolver("!tuple", tuple_pattern, first="(") # Parse shortcuts to `new`, `name`, and `module` yaml.Loader.add_multi_constructor("!new:", _construct_object) yaml.Loader.add_multi_constructor("!name:", _construct_name) yaml.Loader.add_multi_constructor("!module:", _construct_module) yaml.Loader.add_multi_constructor("!apply:", _apply_function) # NOTE: Here we apply a somewhat dirty trick. # We change the yaml object construction to be deep=True by default. # # Sometimes in e.g. !apply: calls which would get passed a dictionary # by reference, the dict got passed empty. # This is to do with pyyaml constructors for e.g. mappings and their # behaviour with the default deep=False # See for example # # In our tests nothing seems to break after changing the default. # But if later weird things start happening in YAML loading, # see this. yaml.constructor.BaseConstructor.construct_object.__defaults__ = ( True, ) # deep=True hparams = yaml.load(yaml_stream, Loader=yaml.Loader) # Change back to normal default: yaml.constructor.BaseConstructor.construct_object.__defaults__ = ( False, ) # deep=False # Remove items that start with "__" removal_keys = [k for k in hparams.keys() if k.startswith("__")] for key in removal_keys: del hparams[key] return hparams
[docs]class RefTag: """Class for dumping !ref tags to yaml Arguments --------- ref_str : str String including yaml keys in `<key>` notation Example ------- See ``dump_hyperpyyaml`` """ yaml_tag = "!ref" def __init__(self, ref_str): self.ref_str = ref_str
[docs] @classmethod def to_yaml(cls, representer, node): return representer.represent_scalar(cls.yaml_tag, node.ref_str)
[docs]class Placeholder: """Class for dumping !PLACEHOLDER tags to yaml Example ------- See ``dump_hyperpyyaml`` """ yaml_tag = "!PLACEHOLDER"
[docs] @classmethod def to_yaml(cls, representer, node): return representer.represent_scalar(cls.yaml_tag, "")
[docs]def dump_hyperpyyaml(yaml_tree, output_stream, *args, **kwargs): r"""Dump yaml including placeholder and reference tags. Arguments --------- yaml_tree : dict An object to dump output_stream : stream A file stream for putting the yaml *args, **kwargs Arguments to forward to ruamel.yaml.YAML().dump() Example ------- >>> to_yaml = {'a': Placeholder(), 'b': RefTag('<a>')} >>> stringio = StringIO() >>> dump_hyperpyyaml(to_yaml, stringio) >>> stringio.getvalue() 'a: !PLACEHOLDER\nb: !ref <a>\n' """ ruamel_yaml = ruamel.yaml.YAML() ruamel_yaml.representer.add_representer(RefTag, RefTag.to_yaml) ruamel_yaml.representer.add_representer(Placeholder, Placeholder.to_yaml) ruamel_yaml.dump(yaml_tree, output_stream, *args, **kwargs)
[docs]def resolve_references(yaml_stream, overrides=None, overrides_must_match=False): r'''Resolves inter-document references, a component of HyperPyYAML. Arguments --------- yaml_stream : stream A file-like object or string with the contents of a yaml file written with the HyperPyYAML syntax. overrides : mapping or str Replacement values, either in a yaml-formatted string or a dict. overrides_must_match : bool Whether an error will be thrown when an override does not match a corresponding key in the yaml_stream. This is the opposite default from ``load_hyperpyyaml`` because ``resolve_references`` doesn't need to be as strict by default. Returns ------- stream A yaml-formatted stream with all references and overrides resolved. Example ------- >>> yaml_string = """ ... constants: ... a: 3 ... b: !ref <constants[a]> ... """ >>> overrides = {'constants': {'a': 4}} >>> resolve_references(yaml_string, overrides).getvalue() 'constants:\n a: 4\n b: 4\n' ''' # find imported yaml location relative to main yaml file file_path = None if hasattr(yaml_stream, "name"): file_path = os.path.dirname(os.path.realpath( # Load once to store references and apply overrides # using ruamel.yaml to preserve the tags ruamel_yaml = ruamel.yaml.YAML() preview = ruamel_yaml.load(yaml_stream) if overrides is not None and overrides != "": if isinstance(overrides, str): overrides = ruamel_yaml.load(overrides) recursive_update(preview, overrides, must_match=overrides_must_match) _walk_tree_and_resolve("root", preview, preview, overrides, file_path) # Dump back to string so we can load with bells and whistles yaml_stream = StringIO() ruamel_yaml.dump(preview, yaml_stream) return yaml_stream
def _walk_tree_and_resolve(key, current_node, tree, overrides, file_path): """A recursive function for resolving ``!ref`` and ``!copy`` tags. Loads additional yaml files if ``!include:`` tags are used. Also throws an error if ``!PLACEHOLDER`` tags are encountered. Arguments --------- key : str The fully-qualified path to current node. current_node : node A node in the yaml tree loaded with ruamel.yaml. tree : node The base node in the yaml tree loaded with ruamel.yaml. overrides : dict A set of overrides to pass to any ``!includes:`` files. file_path : str The location of the directory storing the main yaml file Returns ------- yaml.Node A yaml tree with all references resolved. """ # Walk sequence and resolve if isinstance(current_node, list): for i, sub_node in enumerate(current_node): sub_key = i if key == "root" else f"{key}[{i}]" current_node[i] = _walk_tree_and_resolve( sub_key, sub_node, tree, overrides, file_path ) # Walk mapping and resolve. elif isinstance(current_node, dict): for k, sub_node in current_node.items(): sub_key = k if key == "root" else f"{key}[{k}]" current_node[k] = _walk_tree_and_resolve( sub_key, sub_node, tree, overrides, file_path ) # Base case, handle tags if hasattr(current_node, "tag"): tag_value = current_node.tag.value or "" # Placeholders should have been replaced before now if tag_value == "!PLACEHOLDER": raise ValueError(f"'{key}' is a !PLACEHOLDER and must be replaced.") # Resolve references to other nodes elif tag_value in ["!ref", "!copy"]: copy_mode = tag_value == "!copy" current_node = recursive_resolve( reference=current_node.value, reference_list=[], full_tree=tree, copy_mode=copy_mode, ) # Include external yaml files elif tag_value.startswith("!include:"): filename = tag_value[len("!include:") :] # Update overrides with child keys if isinstance(current_node, dict): if overrides: recursive_update(overrides, current_node) else: overrides = dict(current_node) if file_path is not None: filename = os.path.join(file_path, filename) with open(filename) as f: included_yaml = resolve_references(f, overrides) # Append resolved yaml to current node ruamel_yaml = ruamel.yaml.YAML() current_node = ruamel_yaml.load(included_yaml) # Return node after all resolution is done. return current_node def _make_tuple(loader, node): """Parse scalar node as a list, convert to tuple""" tuple_string = loader.construct_scalar(node) list_string = "[" + tuple_string[1:-1] + "]" parsed_list = yaml.load(list_string, Loader=yaml.Loader) return tuple(parsed_list) def _load_node(loader, node): if isinstance(node, yaml.MappingNode): kwargs = loader.construct_mapping(node, deep=True) return [], kwargs elif isinstance(node, yaml.SequenceNode): args = loader.construct_sequence(node, deep=True) return args, {} return [], {} def _construct_object(loader, callable_string, node): callable_ = pydoc.locate(callable_string) if callable_ is None: raise ImportError("There is no such class as %s" % callable_string) if not inspect.isclass(callable_): raise ValueError( f"!new:{callable_string} should be a class, but is {callable_}" ) try: args, kwargs = _load_node(loader, node) return callable_(*args, **kwargs) except TypeError as e: err_msg = "Invalid argument to class %s" % callable_string e.args = (err_msg, *e.args) raise def _construct_name(loader, callable_string, node): name = pydoc.locate(callable_string) if name is None: raise ImportError("There is no such entity as %s" % callable_string) if not (inspect.isclass(name) or inspect.isroutine(name)): args, kwargs = _load_node(loader, node) if args or kwargs: raise ValueError( f"!name:{callable_string} should be class or function, " f"if you specify args or kwargs. Instead it is {name}" ) return name try: args, kwargs = _load_node(loader, node) return functools.partial(name, *args, **kwargs) except TypeError as e: err_msg = "Invalid argument to callable %s" % callable_string e.args = (err_msg, *e.args) raise def _construct_module(loader, module_name, node): module = pydoc.locate(module_name) if module is None: raise ImportError("There is no such module as %s" % module_name) args, kwargs = _load_node(loader, node) if args != [] or kwargs != {}: raise ValueError("Cannot pass args to module") if not inspect.ismodule(module): raise ValueError( f"!module:{module_name} should be module, but is {module}" ) return module def _apply_function(loader, callable_string, node): callable_ = pydoc.locate(callable_string) if callable_ is None: raise ImportError("There is no such callable as %s" % callable_string) if not inspect.isroutine(callable_): raise ValueError( f"!apply:{callable_string} should be a callable, but is {callable_}" ) try: args, kwargs = _load_node(loader, node) return callable_(*args, **kwargs) except TypeError as e: err_msg = "Invalid argument to callable %s" % callable_string e.args = (err_msg, *e.args) raise
[docs]def deref(ref, full_tree, copy_mode=False): """Find the value referred to by a reference in dot-notation Arguments --------- ref : str The location of the requested value, e.g. 'constants.param' full_tree : dict The dictionary to use for finding values copy_mode : bool Whether to copy the node before dereferencing. Returns ------- node The node in the full_tree dictionary referenced by ``ref``. Example ------- >>> deref('constants[a][b]', {'constants': {'a': {'b': 'c'}}}) 'c' """ # Collect the attribute reference attr = None if "." in ref: ref, attr = ref.split(".", maxsplit=1) # Follow references in dot notation branch = full_tree for part in ref.split("["): part = part.strip("]") if part not in branch: raise ValueError('The reference "%s" is not valid' % ref) branch = branch[part] # Copy node if requested if copy_mode: return copy.deepcopy(branch) # To refer to an attribute, we add this special node if attr is not None: node = ruamel.yaml.comments.CommentedSeq() node += [branch, attr] node.yaml_set_tag("!apply:getattr") return node return branch
[docs]def recursive_resolve(reference, reference_list, full_tree, copy_mode=False): """Resolve a reference to a value, following chained references Arguments --------- reference : str a string containing '<x[y]>' in it where x[y] refers to a scalar node in the file. reference_list : list list of prior references in the chain, in order to catch circular references. full_tree : dict the dictionary in which to find all references and their values. copy_mode : bool Whether to perform a deep copy of the referenced node, rather than a shallow reference to the same object. Returns ------- scalar The dereferenced value, with possible string interpolation and arithmetic parsing. Example ------- >>> tree = {'a': 3, 'b': 'x', 'c': '<a>', 'd': '<c>/<c>', 'e': '<b>/<b>'} >>> recursive_resolve('<d>', [], tree) 1.0 >>> recursive_resolve('<e>', [], tree) 'x/x' """ # Non-greedy operator won't work here, because the fullmatch will # still match if the first and last things happen to be references reference_finder = re.compile(r"<[^>]*>") # Base case, no <key> present if not isinstance(reference, str) or not return reference if len(reference_list) > 1 and reference in reference_list[1:]: raise ValueError("Circular reference detected: ", reference_list) # First check for a full match. These replacements preserve type. if reference_finder.fullmatch(reference): value = deref(reference.strip("<>"), full_tree, copy_mode) reference_list += [reference] return recursive_resolve(value, reference_list, full_tree, copy_mode) # Make sure reference list gets updated to prevent cycles matches = reference_finder.findall(reference) reference_list += [match[0] for match in matches] # Do replacements within the string (interpolation) def replace_fn(x, tree=full_tree, copy_mode=copy_mode): return str(deref(x[0].strip("<>"), full_tree=tree, copy_mode=copy_mode)) sub = reference_finder.sub(replace_fn, reference) reference = recursive_resolve(sub, reference_list, full_tree, copy_mode) # Finally check for arithmetic operations. return parse_arithmetic(reference)
[docs]def parse_arithmetic(reference_string): """Parses simple arithmetic operations in references Adapted from Arguments --------- reference_string : str A string with references and possible arithmetic operations. Returns ------- str Result of parsing and applying the arithmetic. Example ------- >>> parse_arithmetic('2 * 6') 12 """ try: return _ast_eval(ast.parse(reference_string, mode="eval").body) except (TypeError, SyntaxError, KeyError): return reference_string
def _ast_eval(node): ops = { ast.Add: op.add, ast.Sub: op.sub, ast.Mult: op.mul, ast.Div: op.truediv, ast.FloorDiv: op.floordiv, ast.Pow: op.pow, ast.Mod: op.mod, } if isinstance(node, ast.Num): # <number> return node.n elif isinstance(node, ast.BinOp): # <left> <operator> <right> return ops[type(node.op)](_ast_eval(node.left), _ast_eval(node.right)) elif isinstance(node, ast.UnaryOp): # <operator> <operand> e.g., -1 return ops[type(node.op)](_ast_eval(node.operand)) else: raise TypeError(node)
[docs]def recursive_update(d, u, must_match=False): """Similar function to `dict.update`, but for a nested `dict`. From: If you have to a nested mapping structure, for example: {"a": 1, "b": {"c": 2}} Say you want to update the above structure with: {"b": {"d": 3}} This function will produce: {"a": 1, "b": {"c": 2, "d": 3}} Instead of: {"a": 1, "b": {"d": 3}} Arguments --------- d : dict mapping to be updated u : dict mapping to update with must_match : bool Whether to throw an error if the key in `u` does not exist in `d`. Example ------- >>> d = {'a': 1, 'b': {'c': 2}} >>> recursive_update(d, {'b': {'d': 3}}) >>> d {'a': 1, 'b': {'c': 2, 'd': 3}} """ # TODO: Consider cases where u has branch off k, but d does not. # e.g. d = {"a":1}, u = {"a": {"b": 2 }} for k, v in u.items(): if isinstance(v, and k in d: recursive_update(d.get(k, {}), v) elif must_match and k not in d: raise KeyError( f"Override '{k}' not found in: {[key for key in d.keys()]}" ) else: d[k] = v