Python Node API #54
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Python Node API #54
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The `Send` Trait is required by pyo3 for the python binding
Adding `next` and `send_output` requires an async threadpool as the communication Layer defined by the Middleware Layer returns an async Future stream. I solve this issue by adding a tokio runtime on a separater thread that is connected with two channels. One for sending data and one for receiving data. Those channel are then exposed synchronously to Python. This should not be cause for concern as channel are really fast. Looking at Zenoh Python client, they are heavily using `pyo3-asyncio` implementation of futures to pass Rust futures into Python. This can be a solution as well, but, from previous experiment, I'm concerned about performance on such solution. I have experienced that putting futures from Rust into the `asyncio` queue to be slow. I'm concerned also by mixing `async` and `sync` code in Python, as it might be blocking. This might requires 2 threadpool in Python. This might seem as heavy overhead for some operations.
phil-opp
reviewed
Jul 29, 2022
phil-opp
approved these changes
Aug 5, 2022
16 tasks
Since the merge of PyO3/maturin#605 , we can add features flag when maturin build the python project, removing the need to always enabling `extension-module` flag when building. The `extension-module` flag creates crash when building and testing outside of maturin. Previous fix required to disable default feature flag when building and testing which is not ideal.
messense
reviewed
Aug 6, 2022
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Description of the API
The Python API will consist of two principal methods:
nextandsend_output. Those methods will be connected to atokioruntime through channels.Problem
The Python Node API requires an async threadpool as the communication Layer defined by the Middleware Layer returns an async Future stream.
Solution
I solve this issue by adding a
tokioruntime on a separate thread that is connected with two channels. One for sending data and one for receiving data.Those channels are then exposed synchronously to Python. This should not be cause for concern as channels are really fast.
Alternatives
Looking at Zenoh Python client, they are heavily using
pyo3-asyncioimplementation of futures to pass Rust futures into Python.This can be a solution as well, but, from previous experiments, I'm concerned about the performance of this solution. I have experienced that putting futures from Rust into the
asyncioqueue to be slow.I'm concerned also about mixing
asyncandsynccode in Python, as it might be blocking. This might requires 2 threadpools in Python. This might seem a heavy overhead for some operations.