Load and save configs

Use OmegaConf.create() for a YAML string and OmegaConf.load() for a YAML file. Both return an OmegaConf config:

>>> from omegaconf import OmegaConf
>>> cfg = OmegaConf.create("""
... server:
...   port: 80
... """)
>>> cfg.server.port
80

Save and load YAML

OmegaConf.save(cfg, path) writes YAML, and OmegaConf.load(path) reads it back. Paths, filenames, and file objects are accepted. YAML preserves values but not the Python schema of a structured config. Use OmegaConf.to_yaml(cfg) when you need a YAML string or OmegaConf.to_container(cfg) when another Python API needs ordinary dictionaries and lists.

>>> yaml_text = OmegaConf.to_yaml(cfg)
>>> print(yaml_text, end="")
server:
  port: 80

The same operations accept file objects. Loading YAML does not restore a structured config's dataclass or attrs type:

>>> import io
>>> buffer = io.StringIO()
>>> OmegaConf.save(config=cfg, f=buffer)
>>> restored = OmegaConf.load(io.StringIO(buffer.getvalue()))
>>> restored == cfg
True

Pickle

A Python-only pickle round trip retains more OmegaConf type information, but the file may not work across OmegaConf versions and must come from a trusted source. On Python 3.6, structured configs with complex type hints cannot be pickled.

>>> import pickle
>>> restored = pickle.loads(pickle.dumps(cfg))
>>> restored == cfg
True