Metadata-Version: 2.1
Name: typenv
Version: 0.1.4
Summary: Typed environment variable parsing for Python
Home-page: https://github.com/hukkinj1/typenv
License: MIT
Keywords: environment,variables,typed,configuration
Author: hukkinj1
Author-email: hukkinj1@users.noreply.github.com
Requires-Python: >=3.6,<4.0
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Natural Language :: English
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Typing :: Typed
Requires-Dist: python-dotenv (>=0.10.3,<0.14.0)
Project-URL: Changelog, https://github.com/hukkinj1/typenv/blob/master/CHANGELOG.md
Project-URL: Repository, https://github.com/hukkinj1/typenv
Description-Content-Type: text/markdown

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# typenv

<!--- Don't edit the version line below manually. Let bump2version do it for you. -->
> Version 0.1.4

> Typed environment variable parsing for Python

## Background
Typenv does environment variable parsing with an API almost identical to the excellent [environs](https://github.com/sloria/environs). There are a few reasons why typenv might be preferred:
- Type annotated typecast functions: type checkers are able to understand types of parsed environment variables.
- More flexible prefix manipulation of environment variable names.
- Validation of environment variable names.
- Optional automatic uppercasing of environment variable names.
- Ability to generate a .env.example that shows expected types of environment variables.
- Less dependencies. No [marshmallow](https://github.com/marshmallow-code/marshmallow) required.

## Installing
Installing from PyPI repository (https://pypi.org/project/typenv):
```bash
pip install typenv
```

## Usage

### Basics
Set environment variables:
```bash
export NAME='Harry Potter'
export AGE=14
export IS_WIZARD=true
export PATRONUM_SUCCESS_RATE=0.92
export BANK_BALANCE=134599.01
export LUCKY_NUMBERS=7,3,11
export EXTRA_DETAILS='{"friends": ["Hermione", "Ron"]}'
```

Parse the values in Python:
```python
from typenv import Env

env = Env()

NAME = env.str("NAME")  # => "Harry Potter"
AGE = env.int("AGE")  # => 14
IS_WIZARD = env.bool("IS_WIZARD")  # => True
PATRONUM_SUCCESS_RATE = env.float("PATRONUM_SUCCESS_RATE")  # => 0.92
BANK_BALANCE = env.decimal("BANK_BALANCE")  # => decimal.Decimal("134599.01")
LUCKY_NUMBERS = env.list("LUCKY_NUMBERS", subcast=int)  # => [7, 3, 11]
EXTRA_DETAILS = env.json("EXTRA_DETAILS")  # => {"friends": ["Hermione", "Ron"]}

# Optional settings must have a default value
IS_DEATH_EATER = env.bool("IS_DEATH_EATER", default=False)  # => False
```

### Supported types
The types supported by typenv are:
* `env.str`
* `env.int`
* `env.bool`
* `env.float`
* `env.decimal`
* `env.json`
* `env.list`
    * Takes a subcast argument for casting list items to one of `str`, `int` , `bool`, `float` or `decimal.Decimal`

### Default values
Normally, if an environment variable is not found, typenv raises an exception. If a default value is provided, however, that will be returned instead of raising.
```python
from typenv import Env

env = Env()

BOOL = env.bool("NON_EXISTING_NAME", default=False)  # => False
LIST = env.list("NON_EXISTING_NAME", default=["a", "b"])  # => ["a", "b"]
OPTIONAL_INT = env.int("NON_EXISTING_NAME", default=None)  # => None
```

### Name prefixes
TODO: document here

### Name character set
Typenv validates environment variable names. By default, the set of allowed characters includes upper case ASCII letters, digits and the underscore (`_`).

The set of allowed characters can be configured:
```python
from typenv import Env

env = Env(allowed_chars="ABCDEFGHIJKLMNOPQRSTUVWXYZ")
```

### Name uppercasing
```bash
export UPPER_CASE_NAME=true
```
```python
from typenv import Env

# Environment variable names in type cast methods will automatically be upper
# cased when `upper=True` is set here.
env = Env(upper=True)

NAME = env.bool("upper_casE_Name")
```

### Validation
```bash
export NAME='Harry Potter'
export AGE=14
```
```python
from typenv import Env

env = Env()

# A single validator function
NAME = env.str("NAME", validate=lambda n: n.startswith("Harry"))

# A validator function can signal error by raising an exception
def is_positive(num):
    if num <= 0:
        raise Exception("Number is not positive")

# A validator function can alternatively return `False` to signal an error
def is_less_than_thousand(num):
    if num >= 1000:
        return False
    return True

# Multiple validator functions can be passed as an iterable of callables
AGE = env.int("AGE", validate=(is_positive, is_less_than_thousand))
```

### Reading from a `.env` file
TODO: document here

### Dumping parsed values
TODO: document here

## Acknowledgments
The public API of this library is almost an exact copy of [environs](https://github.com/sloria/environs), which is based on [envparse](https://github.com/rconradharris/envparse) and [django-environ](https://github.com/joke2k/django-environ). Credit for the interface goes to the authors of those libraries.

