Force removal of Pyo3 Object to avoid memory leak

This commit fix the memory leak happening in the dora API operator. This
is seemingly due to pyo3 leaking memory on object created in Rust.
Using standard `drop` did not drop the memory on the `PyBytes` included in
the `PyDict`.

See: PyO3/pyo3#1801

Fixes #163

binaries/runtime/src/operator/python.rs

@@ -12,10 +12,10 @@ use dora_operator_api_python::metadata_to_pydict;
 use dora_operator_api_types::DoraStatus;
 use eyre::{bail, eyre, Context};
 use pyo3::{
-    pyclass,
+    ffi, pyclass,
     types::IntoPyDict,
     types::{PyBytes, PyDict},
-    Py, Python,
+    AsPyPointer, Py, Python,
 };
 use std::{
     borrow::Cow,
@@ -139,14 +139,21 @@ pub fn spawn(
 
             let status_enum = Python::with_gil(|py| {
                 let input_dict = PyDict::new(py);
+                let bytes = PyBytes::new(py, &input.data());
 
                 input_dict.set_item("id", input.id.as_str())?;
-                input_dict.set_item("data", PyBytes::new(py, &input.data()))?;
+                input_dict.set_item("data", bytes)?;
                 input_dict.set_item("metadata", metadata_to_pydict(input.metadata(), py))?;
 
-                operator
+                let status_enum = operator
                     .call_method1(py, "on_input", (input_dict, send_output.clone()))
-                    .map_err(traceback)
+                    .map_err(traceback);
+
+                unsafe {
+                    ffi::Py_DECREF(bytes.as_ptr());
+                    ffi::Py_DECREF(input_dict.as_ptr());
+                }
+                status_enum
             })?;
             let status_val = Python::with_gil(|py| status_enum.getattr(py, "value"))
                 .wrap_err("on_input must have enum return value")?;