cube-js/cube · error · minijinja::Error

Python runtime error: {}

Error message

Python runtime error: {}

What it means

Raised when invoking a Python-backed Jinja function but the global Python runtime could not be obtained (py_runtime() failed — interpreter not initialized or the native backend built without Python support). The underlying initialization error follows the colon; the template call never reaches Python code.

Source

Thrown at packages/cubejs-backend-native/src/template/mj_value/python.rs:251

        _state: &mj::State,
        _name: &str,
        _args: &[Value],
    ) -> Result<Value, mj::Error> {
        Err(mj::Error::new(
            minijinja::ErrorKind::InvalidOperation,
            "Unable to call method on Py<Function>",
        ))
    }

    fn call(&self, _state: &mj::State, args: &[Value]) -> Result<Value, mj::Error> {
        let mut arguments = Vec::with_capacity(args.len());

        for arg in args {
            arguments.push(from_minijinja_value(arg)?);
        }

        let py_runtime = py_runtime().map_err(|err| {
            mj::Error::new(
                mj::ErrorKind::EvalBlock,
                format!("Python runtime error: {}", err),
            )
        })?;

        let call_future =
            Python::with_gil(|py| py_runtime.call_async(self.inner.clone_ref(py), arguments));

        let tokio = tokio_runtime().map_err(|err| {
            mj::Error::new(
                mj::ErrorKind::EvalBlock,
                format!("Tokio runtime error: {}", err),
            )
        })?;

        match tokio.block_on(call_future) {
            Ok(r) => Ok(to_minijinja_value(r)),
            Err(err) => Err(mj::Error::new(

View on GitHub (pinned to 7d981676b3)

Solutions

1. Ensure the native backend is built and run with Python support enabled
2. Check earlier logs for the Python runtime initialization failure that caused py_runtime() to error

When it happens

Trigger: Thrown at packages/cubejs-backend-native/src/template/mj_value/python.rs:251 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/a200041e4129d774. Report an issue: GitHub.