sws-config 0.1.0

Minimal pythonic config library for deep learning experiments

sws

Minimal, predictable, footgun-free configuration for deep learning experiments.

The remainder of this readme follows the CODE THEN EXPLAIN layout. Install instructions at the end.

Basics

from sws import Config, lazy

# Create the config and populate the fields with defaults
c = Config()
c.lr = 3e-4
c.wd = c.lr * 0.1  # ERROR, c is write-only. Instead, do:
c.wd = lazy(lambda c: c.lr * 0.1)

# Alternative convenience for short configs:
c = Config(lr=3e-4, wd=lazy(lambda c: c.lr * 0.1))

# Finalizing resolves all fields to plain values, and integrates CLI args:
c = c.finalize(argv=sys.argv[1:])
assert c.lr == 3e-4 and c.wd == 3e-5

train_agi(lr=c.lr, wd=c.wd)

Sws clearly separates two phases: config creation, and config use. At creation time, you build a (possibly nested) Config object, with the option to use lazy(...) to make some field's value depend on the values of other fields. Then, you finalize() the config, which resolves all fields (including lazy ones) into plain concrete values. If desired, finalize() also applies overrides from the commandline.

To avoid subtle bugs common in many config libraries I've used before, at creation time, the Config object is write-only; this forces use of lazy references that get correctly resolved later. At use-time (after finalize()), on the other hand, the FinalConfig object is read-only, which again avoids subtle bugs in complex code.

Nesting

TODO: Continue the doc rewrite from here!

Nested writes and reading after finalize

c = sws.Config()
c.model = {"width": 128}
c.model.depth = 4

f = c.finalize()
assert f.model.width == 128 and f.model.depth == 4

CLI-style overrides (left-to-right) and expression access to c

import sys

base = sws.Config(lr=1.0, model={"width": 128}, foo=0, bar=0)
f = base.finalize(sys.argv[1:])  # e.g.: lr=3 foo=c.lr bar=c.model.width

# Or pass an explicit list:
f = base.finalize(["lr", "3", "foo", "c.lr", "bar", "c.model.width"])  # foo=1.0, then lr=3, then bar=3
assert f.foo == 1.0 and f.lr == 3 and f.bar == 3

Containers and lazy inside containers

c = sws.Config(
    a=2,
    t=(1, lazy(lambda c: c.a + 1)),
    s={1, lazy(lambda c: c.a)},
)
f = c.finalize()
assert f.t == (1, 3) and f.s == frozenset({1, 2})

Cycles and errors

import pytest

c = sws.Config(a=lazy(lambda c: c.b), b=lazy(lambda c: c.a))
wic pytest.raises(sws.CycleError):
    c.finalize()

Install

pip install sws-config

Test

python -m pytest

Authors / License

• Authors: see pyproject.toml.
• License: MIT © Lucas Beyer. See LICENSE for details.