etdl-target-python

The Python developer API for ETDL. Generates a Python @dataclass/ABC/orchestration-function surface from a validated .etdl document, bound to the compiled Rust ETDL runtime via the standard library's ctypes — no third-party package, no compiled Python extension module required. This crate is pure Rust: it never re-implements branch/SLA accounting, retry backoff, or ECEL evaluation in Python — every one of those calls through to etdl-runtime-ffi, the same implementation the Rust target itself uses.

Building this crate never needs Python

etdl-target-python only emits Python source text — it's a plain Rust library used by etdl-cli (etdl compile --target python) or directly via its PythonCodeGenerator. Python 3.9+ is needed only to run the generated code, and a built etdl-runtime-ffi is needed only for anything that touches BranchMonitor/RetryPolicy/Condition.

What it generates

etdl/runtime/
    native.py           # ctypes CDLL bindings to libetdl_runtime_ffi
    branch_monitor.py    # thin facade — delegates to the native runtime
    retry_policy.py       # thin facade — native attempt/backoff loop via a CFUNCTYPE callback
    condition.py           # thin facade — native regex/set-membership evaluation (stdlib json for marshaling)
    errors.py
    publisher.py            # developer-implemented ABC (consequence: send)
<package>/
    messages.py               # one @dataclass per referenced AsyncAPI message
    <tree>_handlers.py          # generated ABC — implement this, don't edit it
    workflow.py                   # generated orchestration + fault-tree probability constants

The etdl/runtime/*.py and workflow.py/*_handlers.py files are regenerated on every compile and marked DO NOT EDIT DIRECTLY. Your own code subclasses the generated handler ABC and Publisher in separate, hand-written modules that are never touched by regeneration.

Usage

etdl compile order-fulfillment.etdl --target python --out-dir ./generated
cargo build -p etdl-runtime-ffi --release   # the native runtime the generated code binds to

ETDL_RUNTIME_LIBRARY=/path/to/libetdl_runtime_ffi.so \
  python3 -c "import your_package.main; your_package.main.main()"

Verified, not just generated

This crate's own test suite runs hand-authored handler/publisher implementations against generated output, executed by a real python3 against a real, compiled etdl-runtime-ffi — including the native retry callback (ctypes transparently reacquires the GIL for the C-to-Python call, the standard documented pattern) and RE2 regex evaluation through etdl_core::condition::matches. See tests/python_runtime_integration.rs.

Full architecture: docs/architecture/targets.md.

License

Apache-2.0