"""The registry module provides some simple convenience functions to enable
applications to dynamically register and look-up codec classes."""
import logging
from contextlib import suppress
logger = logging.getLogger("numcodecs")
codec_registry = {}
entries = {}
def run_entrypoints():
import entrypoints
entries.clear()
entries.update(entrypoints.get_group_named("numcodecs.codecs"))
with suppress(ImportError):
run_entrypoints()
[docs]def get_codec(config):
"""Obtain a codec for the given configuration.
Parameters
----------
config : dict-like
Configuration object.
Returns
-------
codec : Codec
Examples
--------
>>> import numcodecs as codecs
>>> codec = codecs.get_codec(dict(id='zlib', level=1))
>>> codec
Zlib(level=1)
"""
config = dict(config)
codec_id = config.pop('id', None)
cls = codec_registry.get(codec_id)
if cls is None:
if codec_id in entries:
logger.debug("Auto loading codec '%s' from entrypoint", codec_id)
cls = entries[codec_id].load()
register_codec(cls, codec_id=codec_id)
if cls:
return cls.from_config(config)
raise ValueError('codec not available: %r' % codec_id)
[docs]def register_codec(cls, codec_id=None):
"""Register a codec class.
Parameters
----------
cls : Codec class
Notes
-----
This function maintains a mapping from codec identifiers to codec
classes. When a codec class is registered, it will replace any class
previously registered under the same codec identifier, if present.
"""
if codec_id is None:
codec_id = cls.codec_id
logger.debug("Registering codec '%s'", codec_id)
codec_registry[codec_id] = cls