castenv 0.1.0

Smart environment loader with robust casting/normalization. Layers: decouple → dotenv → os.environ.

castenv

castenv is a smart environment loader with robust casting/normalization, that uses python-decouple (if installed), python-dotenv with a Fallback to os.environ

current_version = "v0.1.0"

1. python-decouple (if installed)
2. python-dotenv (if installed; auto-discovers .env, .env.local, .env.{env}, .env.{env}.local across cwd+parents)
3. Fallback to os.environ

No per-call config — just castenv.get_env("KEY"), like os.environ.get but smarter.

Quick start

Install

pip install castenv
# Optional extras:
pip install "castenv[dotenv]"
pip install "castenv[decouple]"

Example

import castenv as env

# Optional one-time setup (else: auto cwd+parents):
# env.configure(search_dirs=[BASE_DIR], env_name="prod")

DATABASE_URL = env.get_env("DATABASE_URL", None)
DEBUG = env.env_bool("DEBUG", False)
DEBUG2 = env.get_env("DEBUG2", True)
TIMEOUT_SECS = env.get_env("TIMEOUT", "1m30s")  # -> seconds float (90.0)
TIMEOUT_HOURS = env.get_env("HOURS", "2d1h")  # -> seconds float (176400.0)
CACHE_BYTES = env.get_env("CACHE", "256MB")     # -> bytes int (256000000)
ALLOWED = env.get_env(
    "ALLOWED_HOSTS",
    "localhost,127.0.0.1",
    normalize_kwargs={"parse_lists": True}
)
PORT   = env.get_env("PORT", 8080)     # -> 8080 (int)
OPTS   = env.get_env("OPTS", {"x": 1}) # -> {"x": 1} (dict)
SCALE = env.get_env("SCALE", "50%", normalize_kwargs={"percent_mode": "fraction"})
TAX   = env.get_env("PORT", 15.5)     # -> 15.5 (float)

print("DATABASE_URL:", DATABASE_URL)
print("DEBUG (bool) [env_bool]:", DEBUG)
print("DEBUG2 (bool) [get_env]:", DEBUG2)
print("TIMEOUT (secs):", TIMEOUT_SECS)
print("TIMEOUT_HOURS (secs):", TIMEOUT_HOURS)
print("CACHE (bytes):", CACHE_BYTES)
print("ALLOWED_HOSTS (list):", ALLOWED)
print("PORT (int):", PORT)
print("OPTS (dict):", OPTS)
print("SCALE (float) [0-1]:", SCALE)
print("TAX (float):", TAX)

Normalization highlights

• None via missing/empty/null/none
• Booleans (true/false/on/off/yes/no/1/0)
• Numbers (int/float/sci + 0x/0b/0o)
• Durations (1h30m, 500ms) → seconds (float)
• Sizes (256MB, 1GiB, 512k) → bytes (int)
• JSON ({"a":1} / ["x","y"])
• Lists (a,b,c) with recursive normalization
• Percentages (50%) as string/number/fraction (configurable)
• Env interpolation (URL=${BASE:-http://localhost}/v1)
• ~ expansion

Testing overrides

from pathlib import Path
import castenv as env

with env.using(search_dirs=[Path("tests/envs")], env_name="test"):
    assert env.get_env("SOME_KEY") == "value"

Development

Virtual Environments

python -m venv venv

Mac/Linux

source venv/bin/activate

Windows

venv/scripts/activate

Install Requirements

pip install poetry
poetry install

Install Optional Requirements

poetry install --extras "decouple"
poetry install --extras "dotenv"
poetry install --extras "decouple dotenv"

Test

pytest
coverage run -m pytest
coverage report
coverage html
mypy --html-report mypy_report .
flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics --format=html --htmldir="flake8_report/basic" --exclude=venv
flake8 . --count --exit-zero --max-complexity=11 --max-line-length=127 --statistics --format=html --htmldir="flake8_report/complexity" --exclude=venv

BumpVer

With the CLI command bumpver, you can search for and update version strings in your project files. It has a flexible pattern syntax to support many version schemes (SemVer, CalVer or otherwise). Run BumbVer with:

bumpver update --major --dry
bumpver update --major

bumpver update --minor --dry
bumpver update --minor

bumpver update --patch --dry
bumpver update --patch

Build

poetry build

Publish

poetry publish

License

MIT