from __future__ import annotations
import ast
import base64
import builtins # Explicitly use builtins.set as 'set' will be shadowed by a function
import json
import os
import site
import sys
import threading
import warnings
from collections.abc import Mapping, Sequence
from typing import Any, Literal
import yaml
no_default = "__no_default__"
def _get_paths():
"""Get locations to search for YAML configuration files.
This logic exists as a separate function for testing purposes.
"""
paths = [
os.getenv("DASK_ROOT_CONFIG", "/etc/dask"),
os.path.join(sys.prefix, "etc", "dask"),
*[os.path.join(prefix, "etc", "dask") for prefix in site.PREFIXES],
os.path.join(os.path.expanduser("~"), ".config", "dask"),
]
if "DASK_CONFIG" in os.environ:
paths.append(os.environ["DASK_CONFIG"])
# Remove duplicate paths while preserving ordering
paths = list(reversed(list(dict.fromkeys(reversed(paths)))))
return paths
paths = _get_paths()
if "DASK_CONFIG" in os.environ:
PATH = os.environ["DASK_CONFIG"]
else:
PATH = os.path.join(os.path.expanduser("~"), ".config", "dask")
config: dict = {}
global_config = config # alias
config_lock = threading.Lock()
defaults: list[Mapping] = []
def canonical_name(k: str, config: dict) -> str:
"""Return the canonical name for a key.
Handles user choice of '-' or '_' conventions by standardizing on whichever
version was set first. If a key already exists in either hyphen or
underscore form, the existing version is the canonical name. If neither
version exists the original key is used as is.
"""
try:
if k in config:
return k
except TypeError:
# config is not a mapping, return the same name as provided
return k
altk = k.replace("_", "-") if "_" in k else k.replace("-", "_")
if altk in config:
return altk
return k
[docs]def update(old: dict, new: Mapping, priority: Literal["old", "new"] = "new") -> dict:
"""Update a nested dictionary with values from another
This is like dict.update except that it smoothly merges nested values
This operates in-place and modifies old
Parameters
----------
priority: string {'old', 'new'}
If new (default) then the new dictionary has preference.
Otherwise the old dictionary does.
Examples
--------
>>> a = {'x': 1, 'y': {'a': 2}}
>>> b = {'x': 2, 'y': {'b': 3}}
>>> update(a, b) # doctest: +SKIP
{'x': 2, 'y': {'a': 2, 'b': 3}}
>>> a = {'x': 1, 'y': {'a': 2}}
>>> b = {'x': 2, 'y': {'b': 3}}
>>> update(a, b, priority='old') # doctest: +SKIP
{'x': 1, 'y': {'a': 2, 'b': 3}}
See Also
--------
dask.config.merge
"""
for k, v in new.items():
k = canonical_name(k, old)
if isinstance(v, Mapping):
if k not in old or old[k] is None:
old[k] = {}
update(old[k], v, priority=priority)
else:
if priority == "new" or k not in old:
old[k] = v
return old
[docs]def merge(*dicts: Mapping) -> dict:
"""Update a sequence of nested dictionaries
This prefers the values in the latter dictionaries to those in the former
Examples
--------
>>> a = {'x': 1, 'y': {'a': 2}}
>>> b = {'y': {'b': 3}}
>>> merge(a, b) # doctest: +SKIP
{'x': 1, 'y': {'a': 2, 'b': 3}}
See Also
--------
dask.config.update
"""
result: dict = {}
for d in dicts:
update(result, d)
return result
def _load_config_file(path: str) -> dict | None:
"""A helper for loading a config file from a path, and erroring
appropriately if the file is malformed."""
try:
with open(path) as f:
config = yaml.safe_load(f.read())
except OSError:
# Ignore permission errors
return None
except Exception as exc:
raise ValueError(
f"A dask config file at {path!r} is malformed, original error "
f"message:\n\n{exc}"
) from None
if config is not None and not isinstance(config, dict):
raise ValueError(
f"A dask config file at {path!r} is malformed - config files must have "
f"a dict as the top level object, got a {type(config).__name__} instead"
)
return config
def collect_yaml(paths: Sequence[str] = paths) -> list[dict]:
"""Collect configuration from yaml files
This searches through a list of paths, expands to find all yaml or json
files, and then parses each file.
"""
# Find all paths
file_paths = []
for path in paths:
if os.path.exists(path):
if os.path.isdir(path):
try:
file_paths.extend(
sorted(
os.path.join(path, p)
for p in os.listdir(path)
if os.path.splitext(p)[1].lower()
in (".json", ".yaml", ".yml")
)
)
except OSError:
# Ignore permission errors
pass
else:
file_paths.append(path)
configs = []
# Parse yaml files
for path in file_paths:
config = _load_config_file(path)
if config is not None:
configs.append(config)
return configs
def collect_env(env: Mapping[str, str] | None = None) -> dict:
"""Collect config from environment variables
This grabs environment variables of the form "DASK_FOO__BAR_BAZ=123" and
turns these into config variables of the form ``{"foo": {"bar-baz": 123}}``
It transforms the key and value in the following way:
- Lower-cases the key text
- Treats ``__`` (double-underscore) as nested access
- Calls ``ast.literal_eval`` on the value
Any serialized config passed via ``DASK_INTERNAL_INHERIT_CONFIG`` is also set here.
"""
if env is None:
env = os.environ
if "DASK_INTERNAL_INHERIT_CONFIG" in env:
d = deserialize(env["DASK_INTERNAL_INHERIT_CONFIG"])
else:
d = {}
for name, value in env.items():
if name.startswith("DASK_"):
varname = name[5:].lower().replace("__", ".")
try:
d[varname] = ast.literal_eval(value)
except (SyntaxError, ValueError):
d[varname] = value
result: dict = {}
set(d, config=result)
return result
[docs]def ensure_file(
source: str, destination: str | None = None, comment: bool = True
) -> None:
"""
Copy file to default location if it does not already exist
This tries to move a default configuration file to a default location if
if does not already exist. It also comments out that file by default.
This is to be used by downstream modules (like dask.distributed) that may
have default configuration files that they wish to include in the default
configuration path.
Parameters
----------
source : string, filename
Source configuration file, typically within a source directory.
destination : string, directory
Destination directory. Configurable by ``DASK_CONFIG`` environment
variable, falling back to ~/.config/dask.
comment : bool, True by default
Whether or not to comment out the config file when copying.
"""
if destination is None:
destination = PATH
# destination is a file and already exists, never overwrite
if os.path.isfile(destination):
return
# If destination is not an existing file, interpret as a directory,
# use the source basename as the filename
directory = destination
destination = os.path.join(directory, os.path.basename(source))
try:
if not os.path.exists(destination):
os.makedirs(directory, exist_ok=True)
# Atomically create destination. Parallel testing discovered
# a race condition where a process can be busy creating the
# destination while another process reads an empty config file.
tmp = "%s.tmp.%d" % (destination, os.getpid())
with open(source) as f:
lines = list(f)
if comment:
lines = [
"# " + line if line.strip() and not line.startswith("#") else line
for line in lines
]
with open(tmp, "w") as f:
f.write("".join(lines))
try:
os.rename(tmp, destination)
except OSError:
os.remove(tmp)
except OSError:
pass
[docs]class set:
"""Temporarily set configuration values within a context manager
Parameters
----------
arg : mapping or None, optional
A mapping of configuration key-value pairs to set.
**kwargs :
Additional key-value pairs to set. If ``arg`` is provided, values set
in ``arg`` will be applied before those in ``kwargs``.
Double-underscores (``__``) in keyword arguments will be replaced with
``.``, allowing nested values to be easily set.
Examples
--------
>>> import dask
Set ``'foo.bar'`` in a context, by providing a mapping.
>>> with dask.config.set({'foo.bar': 123}):
... pass
Set ``'foo.bar'`` in a context, by providing a keyword argument.
>>> with dask.config.set(foo__bar=123):
... pass
Set ``'foo.bar'`` globally.
>>> dask.config.set(foo__bar=123) # doctest: +SKIP
See Also
--------
dask.config.get
"""
config: dict
# [(op, path, value), ...]
_record: list[tuple[Literal["insert", "replace"], tuple[str, ...], Any]]
def __init__(
self,
arg: Mapping | None = None,
config: dict = config,
lock: threading.Lock = config_lock,
**kwargs,
):
with lock:
self.config = config
self._record = []
if arg is not None:
for key, value in arg.items():
key = check_deprecations(key)
self._assign(key.split("."), value, config)
if kwargs:
for key, value in kwargs.items():
key = key.replace("__", ".")
key = check_deprecations(key)
self._assign(key.split("."), value, config)
def __enter__(self):
return self.config
def __exit__(self, type, value, traceback):
for op, path, value in reversed(self._record):
d = self.config
if op == "replace":
for key in path[:-1]:
d = d.setdefault(key, {})
d[path[-1]] = value
else: # insert
for key in path[:-1]:
try:
d = d[key]
except KeyError:
break
else:
d.pop(path[-1], None)
def _assign(
self,
keys: Sequence[str],
value: Any,
d: dict,
path: tuple[str, ...] = (),
record: bool = True,
) -> None:
"""Assign value into a nested configuration dictionary
Parameters
----------
keys : Sequence[str]
The nested path of keys to assign the value.
value : object
d : dict
The part of the nested dictionary into which we want to assign the
value
path : tuple[str], optional
The path history up to this point.
record : bool, optional
Whether this operation needs to be recorded to allow for rollback.
"""
key = canonical_name(keys[0], d)
path = path + (key,)
if len(keys) == 1:
if record:
if key in d:
self._record.append(("replace", path, d[key]))
else:
self._record.append(("insert", path, None))
d[key] = value
else:
if key not in d:
if record:
self._record.append(("insert", path, None))
d[key] = {}
# No need to record subsequent operations after an insert
record = False
self._assign(keys[1:], value, d[key], path, record=record)
[docs]def collect(paths: list[str] = paths, env: Mapping[str, str] | None = None) -> dict:
"""
Collect configuration from paths and environment variables
Parameters
----------
paths : list[str]
A list of paths to search for yaml config files
env : Mapping[str, str]
The system environment variables
Returns
-------
config: dict
See Also
--------
dask.config.refresh: collect configuration and update into primary config
"""
if env is None:
env = os.environ
configs = collect_yaml(paths=paths)
configs.append(collect_env(env=env))
return merge(*configs)
[docs]def refresh(
config: dict = config, defaults: list[Mapping] = defaults, **kwargs
) -> None:
"""
Update configuration by re-reading yaml files and env variables
This mutates the global dask.config.config, or the config parameter if
passed in.
This goes through the following stages:
1. Clearing out all old configuration
2. Updating from the stored defaults from downstream libraries
(see update_defaults)
3. Updating from yaml files and environment variables
Note that some functionality only checks configuration once at startup and
may not change behavior, even if configuration changes. It is recommended
to restart your python process if convenient to ensure that new
configuration changes take place.
See Also
--------
dask.config.collect: for parameters
dask.config.update_defaults
"""
config.clear()
for d in defaults:
update(config, d, priority="old")
update(config, collect(**kwargs))
[docs]def get(
key: str,
default: Any = no_default,
config: dict = config,
override_with: Any | None = None,
) -> Any:
"""
Get elements from global config
If ``override_with`` is not None this value will be passed straight back.
Useful for getting kwarg defaults from Dask config.
Use '.' for nested access
Examples
--------
>>> from dask import config
>>> config.get('foo') # doctest: +SKIP
{'x': 1, 'y': 2}
>>> config.get('foo.x') # doctest: +SKIP
1
>>> config.get('foo.x.y', default=123) # doctest: +SKIP
123
>>> config.get('foo.y', override_with=None) # doctest: +SKIP
2
>>> config.get('foo.y', override_with=3) # doctest: +SKIP
3
See Also
--------
dask.config.set
"""
if override_with is not None:
return override_with
keys = key.split(".")
result = config
for k in keys:
k = canonical_name(k, result)
try:
result = result[k]
except (TypeError, IndexError, KeyError):
if default is not no_default:
return default
else:
raise
return result
def rename(aliases: Mapping, config: dict = config) -> None:
"""Rename old keys to new keys
This helps migrate older configuration versions over time
"""
old = []
new = {}
for o, n in aliases.items():
value = get(o, None, config=config)
if value is not None:
old.append(o)
new[n] = value
for k in old:
del config[canonical_name(k, config)] # TODO: support nested keys
set(new, config=config)
def update_defaults(
new: Mapping, config: dict = config, defaults: list[Mapping] = defaults
) -> None:
"""Add a new set of defaults to the configuration
It does two things:
1. Add the defaults to a global collection to be used by refresh later
2. Updates the global config with the new configuration
prioritizing older values over newer ones
"""
defaults.append(new)
update(config, new, priority="old")
[docs]def expand_environment_variables(config: Any) -> Any:
"""Expand environment variables in a nested config dictionary
This function will recursively search through any nested dictionaries
and/or lists.
Parameters
----------
config : dict, iterable, or str
Input object to search for environment variables
Returns
-------
config : same type as input
Examples
--------
>>> expand_environment_variables({'x': [1, 2, '$USER']}) # doctest: +SKIP
{'x': [1, 2, 'my-username']}
"""
if isinstance(config, Mapping):
return {k: expand_environment_variables(v) for k, v in config.items()}
elif isinstance(config, str):
return os.path.expandvars(config)
elif isinstance(config, (list, tuple, builtins.set)):
return type(config)(expand_environment_variables(v) for v in config)
else:
return config
deprecations = {
"fuse_ave_width": "optimization.fuse.ave-width",
"fuse_max_height": "optimization.fuse.max-height",
"fuse_max_width": "optimization.fuse.max-width",
"fuse_subgraphs": "optimization.fuse.subgraphs",
"fuse_rename_keys": "optimization.fuse.rename-keys",
"fuse_max_depth_new_edges": "optimization.fuse.max-depth-new-edges",
# See https://github.com/dask/distributed/pull/4916
"ucx.cuda_copy": "distributed.ucx.cuda_copy",
"ucx.tcp": "distributed.ucx.tcp",
"ucx.nvlink": "distributed.ucx.nvlink",
"ucx.infiniband": "distributed.ucx.infiniband",
"ucx.rdmacm": "distributed.ucx.rdmacm",
"ucx.net-devices": "distributed.ucx.net-devices",
"ucx.reuse-endpoints": "distributed.ucx.reuse-endpoints",
"rmm.pool-size": "distributed.rmm.pool-size",
"shuffle": "dataframe.shuffle.algorithm",
"dataframe.shuffle.algorithm": "dataframe.shuffle.method",
"dataframe.shuffle-compression": "dataframe.shuffle.compression",
}
def check_deprecations(key: str, deprecations: dict = deprecations) -> str:
"""Check if the provided value has been renamed or removed
Parameters
----------
key : str
The configuration key to check
deprecations : Dict[str, str]
The mapping of aliases
Examples
--------
>>> deprecations = {"old_key": "new_key", "invalid": None}
>>> check_deprecations("old_key", deprecations=deprecations) # doctest: +SKIP
UserWarning: Configuration key "old_key" has been deprecated. Please use "new_key" instead.
>>> check_deprecations("invalid", deprecations=deprecations)
Traceback (most recent call last):
...
ValueError: Configuration value "invalid" has been removed
>>> check_deprecations("another_key", deprecations=deprecations)
'another_key'
Returns
-------
new: str
The proper key, whether the original (if no deprecation) or the aliased
value
"""
if key in deprecations:
new = deprecations[key]
if new:
warnings.warn(
'Configuration key "{}" has been deprecated. '
'Please use "{}" instead'.format(key, new)
)
return new
else:
raise ValueError(f'Configuration value "{key}" has been removed')
else:
return key
def serialize(data: Any) -> str:
"""Serialize config data into a string.
Typically used to pass config via the ``DASK_INTERNAL_INHERIT_CONFIG`` environment variable.
Parameters
----------
data: json-serializable object
The data to serialize
Returns
-------
serialized_data: str
The serialized data as a string
"""
return base64.urlsafe_b64encode(json.dumps(data).encode()).decode()
def deserialize(data: str) -> Any:
"""De-serialize config data into the original object.
Typically when receiving config via the ``DASK_INTERNAL_INHERIT_CONFIG`` environment variable.
Parameters
----------
data: str
String serialized by :func:`dask.config.serialize`
Returns
-------
deserialized_data: obj
The de-serialized data
"""
return json.loads(base64.urlsafe_b64decode(data.encode()).decode())
def _initialize() -> None:
fn = os.path.join(os.path.dirname(__file__), "dask.yaml")
with open(fn) as f:
_defaults = yaml.safe_load(f)
update_defaults(_defaults)
refresh()
_initialize()