Add README

README.md

@@ -1,10 +1,72 @@
 # Extism Python Host SDK
 
-See [https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/](https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/).
+This repo contains the Python package for integrating with the
+[Extism](https://extism.org/) Webassembly framework. Install this library into
+your Python application host to run Extism WebAssembly guest plug-ins.
 
+> **Note**: :warning: This repo is 1.0 alpha version of the Python SDK and is a work in
+> progress. :warning:
+>
+> We'd love any feedback you have on it, but consider using the supported
+> python SDK in
+> [extism/extism](https://github.com/extism/extism/tree/main/python) until we
+> hit 1.0.
+
+```python
+import extism
+import json
+
+manifest = {"wasm": [{"url": "https://github.com/extism/plugins/releases/latest/download/count_vowels.wasm"}]}
+with extism.Plugin(manifest, wasi=True) as plugin:
+    wasm_vowel_count = plugin.call(
+        "count_vowels",
+        "hello world",
+        parse = lambda output: json.loads(bytes(output).decode('utf-8'))
+    )
+print(wasm_vowel_count) # {'count': 3, 'total': 3, 'vowels': 'aeiouAEIOU'}
+```
+
+## Installation
+
+Install this package from [PyPI][pypi]:
+
+```shell
+# using pip
+$ pip install extism==1.0.0rc0 --pre
+
+# using poetry
+$ poetry add extism=^1.0.0rc0 --allow-prereleases
+```
+
+The `extism` package should install an appropriate `extism_sys` dependency
+containing a prebuilt shared object for your system. We support the following
+targets:
+
+- MacOS 11.0+, `arm64`
+- MacOS 10.7+, `x86_64`
+- Manylinux 2.17+, `aarch64`
+- Manylinux 2.17+, `x86_64`
+- MUSL Linux 1.2+, `aarch64`
+- Windows (MSVC), `x86_64`
+
+If you need support for a different platform or architecture, please [let us know][let-us-know]!
+
+[let-us-know]: https://github.com/extism/extism/issues/new?title=Please+support+extism_sys+on+my+platform&labels=python&body=Hey%21+Could+you+support+%24PLATFORM+and%2For+%24ARCH%3F
+
+## Documentation
+
+Check out the docs:
+
+- [Getting Started](https://extism.readthedocs.org/en/latest/)
+- [API docs](https://extism.readthedocs.org/en/latest/)
 
 ## Development
 
+### Local dev
+
+Install [just](https://just.systems). Running `just test` should install all
+other prerequisites.
+
 ### Release workflow
 
 1. Create a semver-formatted git tag (`git tag v1.0.0`).
@@ -16,3 +78,6 @@ See [https://extism.org/docs/integrate-into-your-codebase/python-host-sdk/](http
 6. Wait for [the Release workflow to run](https://github.com/extism/python-sdk/actions/workflows/release.yaml).
 7. Once the release workflow completes, you should be able to `pip install extism==${YOUR_TAG}` from PyPI.
 
+## LICENSE
+
+[BSD-3-Clause](./LICENSE)