GoKawiilRunning Python code in a sandbox with MicroPython and WASM
I’ve been experimenting with different approaches to running code in a sandbox for several years now, but my latest attempt feels like it might finally have all of the characteristics I’ve been looking for. I’ve released it as an alpha package called micropython-wasm, and I’m using it for a code execution sandbox plugin for Datasette Agent called datasette-agent-micropython.
Why do I want a sandbox?
My key open source projects—Datasette, LLM, even sqlite-utils—all support plugins.
I absolutely love plugins as a mechanism for extending software. A carefully designed plugin system reduces the risk involved in trying new things to almost nothing—even the wildest ideas won’t leave a lasting influence on the core application itself. My software can grow a new feature overnight and I don’t even have to review a pull request!
There’s one major drawback: my plugin systems all use Python and Pluggy, and plugin code executes with full privileges within my applications. A buggy or malicious plugin could break everything or leak private data.
I’d love to be able to run plugin-style code in an environment where it is unable to read unapproved files, connect to a network, or generally operate in a way that’s risky or harmful to the rest of the application or the user’s computer.
My interest covers more than just plugins. For Datasette in particular there are many features I’d like to support where arbitrary code execution would be useful. I’ve already experimented with this for Datasette Enrichments, where code can be used to transform values stored in a table. I’d love to build a mechanism where you can run code on a schedule that fetches JSON from an approved location, runs a tiny bit of code to reformat it into a list of dictionaries, then inserts those as rows in a SQLite database table.
What I want from a sandbox
My goal is to execute code safely within my own Python applications. Here’s what I need:
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