Fastly Compute Python SDK

Experimental Python SDK for Fastly Compute services.

Features

• Multiple Framework Support: Examples with Bottle, Flask, and more
• WIT Bindings: Auto-generated Python bindings from Fastly's WIT files
• WSGI Compatibility: Host any WSGI-compatible web framework
• Testing Framework: Comprehensive viceroy-based integration testing
• Type Safety: Full type hints and IDE support

Quick Start

Build and Run

make serve                    # Serve default example (Bottle)
make serve EXAMPLE=flask-app  # Serve Flask example

Visit http://127.0.0.1:7676/hello/world or http://127.0.0.1:7676/info

Available Examples

make list-examples           # List all examples
make build-all              # Build all examples

Testing

make test                   # Run integration tests

Development

Build Tool Development

The fastly-compute-py build tool is written in Rust. By default, the Makefile uses cargo run (DEV_MODE=1), which means:

• No installation needed - the tool runs directly via cargo
• Always up-to-date - changes to Rust code are automatically picked up
• Fast incremental builds - cargo handles recompilation efficiently

Simply edit the Rust code in crates/fastly-compute-py/ and run make - that's it!

Alternative: Using the Python Entry Point

To test the installed fastly-compute-py command (how end users will invoke it):

make DEV_MODE=0   # Uses `uv run fastly-compute-py` instead of `cargo run`

Code Quality

make format         # Format code (Python + Rust)
make lint           # Run linter (Python + Rust)
make lint-fix       # Auto-fix linting issues (Python + Rust)

Building Examples

make build/my-app.wasm      # Build specific example
make clean                  # Clean all build artifacts

Status

Currently demonstrates:

• Building pure Python into WebAssembly components
• Creating Python bindings from Fastly's WIT files
• Hosting web frameworks by adapting Fastly's API to WSGI
• Comprehensive testing with viceroy integration

Caveats

• Any native Python modules need to be compiled against WASI. Few are at the moment. However, Joel has done some, and the changes needed aren't extensive.

Contributing

See CONTRIBUTING.md.