// NOTE: Other pyo3 python libraries have had issues with using tokio

// behind a forking app-server like `gunicorn`

// If we run into that problem, in the future we can look to `delta-rs`

// which adds a check in that disallows calls from a forked process

// https://github.com/delta-io/delta-rs/blob/87010461cfe01563d91a4b9cd6fa468e2ad5f283/python/src/utils.rs#L10-L31

static RUNTIME: OnceLock<TokioRuntime> = OnceLock::new();

RUNTIME.get_or_init(|| TokioRuntime(tokio::runtime::Runtime::new().unwrap()))

static IS_IPYTHON_ENV: OnceLock<bool> = OnceLock::new();

IS_IPYTHON_ENV.get_or_init(|| {

py.import("IPython")

.and_then(|ipython| ipython.call_method0("get_ipython"))

.map(|ipython| !ipython.is_none())

.unwrap_or(false)

})

F: Future + Send,

F::Output: Send,

let runtime: &Runtime = &get_tokio_runtime().0;

const INTERVAL_CHECK_SIGNALS: Duration = Duration::from_millis(1_000);

py.allow_threads(|| {

runtime.block_on(async {

tokio::pin!(fut);

loop {

tokio::select! {

res = &mut fut => break Ok(res),

_ = sleep(INTERVAL_CHECK_SIGNALS) => {

Python::with_gil(|py| py.check_signals())?;

}

}

}

})

})

Ok(match value {

"immutable" => Volatility::Immutable,

"stable" => Volatility::Stable,

"volatile" => Volatility::Volatile,

value => {

return Err(PyDataFusionError::Common(format!(

"Unsupported volatility type: `{value}`, supported \

)))

}

})

let capsule_name = capsule.name()?;

if capsule_name.is_none() {

return Err(PyValueError::new_err(format!(

"Expected {name} PyCapsule to have name set."

)));

}

let capsule_name = capsule_name.unwrap().to_str()?;

if capsule_name != name {

return Err(PyValueError::new_err(format!(

"Expected name '{name}' in PyCapsule, instead got '{capsule_name}'"

)));

}

Ok(())

obj: &Bound<PyAny>,

) -> PyResult<Option<Arc<dyn TableProvider>>> {

if obj.hasattr("__datafusion_table_provider__")? {

let capsule = obj.getattr("__datafusion_table_provider__")?.call0()?;

let capsule = capsule.downcast::<PyCapsule>().map_err(py_datafusion_err)?;

validate_pycapsule(capsule, "datafusion_table_provider")?;

let provider = unsafe { capsule.reference::<FFI_TableProvider>() };

let provider: ForeignTableProvider = provider.into();

Ok(Some(Arc::new(provider)))

} else {

Ok(None)

}

// convert Python object to PyScalarValue to ScalarValue

let pa = py.import("pyarrow")?;

// Convert Python object to PyArrow scalar

let scalar = pa.call_method1("scalar", (obj,))?;

// Convert PyArrow scalar to PyScalarValue

let py_scalar = PyScalarValue::extract_bound(scalar.as_ref())

.map_err(|e| PyValueError::new_err(format!("Failed to extract PyScalarValue: {e}")))?;

// Convert PyScalarValue to ScalarValue

Ok(py_scalar.into())