How to set up IronFlow¶

If you only need the prefect_compat library, start with Installation — pip install ironflow-prefect-compat or uv pip install ironflow-prefect-compat from PyPI when a wheel matches your platform.

This page consolidates the repository / source path: Python environment, Rust rust-engine build, and the environment variables the shim respects. For a minimal end-to-end check after setup, see Quick start (demo flow).

1. Get the code¶

Pick a release tag for stability, or use main for the latest development state.

git clone https://github.com/PPPSDavid/rust-based-prefect.git
cd rust-based-prefect
git checkout v0.1.1   # optional: replace with current tag

2. Python environment¶

Conda (recommended; matches maintainers’ stack)

mamba env create -f environment.yml    # or: conda env create -f environment.yml
conda activate ironflow-dev

venv + pip (no conda)

python -m venv .venv
# Windows: .venv\Scripts\activate
# macOS/Linux: source .venv/bin/activate
python -m pip install -r requirements-ci.txt

Use Python 3.11+ (environment.yml may pin 3.12).

3. Build the Rust engine¶

From the repository root:

cargo build --manifest-path rust-engine/Cargo.toml

For release builds:

cargo build --release --manifest-path rust-engine/Cargo.toml

4. Environment variables¶

Variable	Purpose
`IRONFLOW_RUST_LIB`	Path to the built `ironflow_engine` shared library if it is not under `rust-engine/target/` (for example custom output directory). If unset, the shim searches default `cargo` output paths. Without a native library, some code paths use Python fallbacks where implemented—the intended stack is always build the `cdylib`.
`IRONFLOW_HISTORY_PATH`	When set to a file path, flow history can be appended as JSONL for inspection and tooling (see the repository README for defaults and behavior).
`PYTHONPATH`	Set to `python-shim/src` at the repo root so `import prefect_compat` works without an editable install (used in Quick start).

Task-runner–related optional variables (IRONFLOW_TASK_RUNNER, IRONFLOW_TASK_RUNNER_THREAD_POOL_MAX_WORKERS, IRONFLOW_TASK_RUNNER_PROCESS_POOL_MAX_WORKERS) are described in Runners.

5. Verify¶

Run the Quick start (demo flow) (python python-shim/examples/flow_ironflow.py with PYTHONPATH set).
Optionally run tests from the repo root:

python -m pytest python-shim/tests static-planner/tests benchmarks/tests
cargo test --manifest-path rust-engine/Cargo.toml

6. Install only `prefect_compat` in another project (narrow path)¶

Preferred path when available: pip install ironflow-prefect-compat (production PyPI) or use the TestPyPI index pair documented in Installation.

You can also pip install from Git:

python -m pip install "git+https://github.com/PPPSDavid/rust-based-prefect.git@v0.1.1#subdirectory=python-shim"

That package does not ship rust-engine; build the native library separately and set IRONFLOW_RUST_LIB, or accept Python fallbacks. See also Installation for the same material with slightly different emphasis.