Kallichore Builds

This repository hosts builds of Kallichore, Positron's Jupyter kernel supervisor.

What is Kallichore?

Kallichore is a high-performance, headless Jupyter kernel supervisor written in Rust.

It is used by the Positron IDE to provide durable Jupyter kernel sessions, especially in Posit Workbench. It takes care of much of the minutiae of Jupyter kernel management (ZeroMQ, process interop, lifecycle supervision, etc.) and exposes a high-level API that Positron uses to control kernel sessions and to send and receive Jupyter messages.

Kallichore is a companion to Posit's Amalthea and Ark projects. Like Amalthea, it is a Jupyter-adjacent project named after one of Jupiter's moons. Kallichore is also one of the Muses.

Here's how Kallichore functions in the larger Positron ecosystem for e.g. an R session:

graph TD
p[Positron] -- Positron API --> r[R Language Pack]
r -- Positron API --> p
r --> kp[Kallichore Plugin] 
kp --> r
kp -- Kallichore API --> k[Kallichore]
k -- Kallichore API --> kp
k -- Jupyter over ZeroMQ --> rk[R Kernel]
rk -- Jupyter over ZeroMQ --> k
kp -- Jupyter over WebSocket --> k
rk -- LSP over TCP --> r

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What are these builds?

These are binary release builds of kcserver, the Kallichore server, for all major operating systems.

What are they for?

These builds are bundled as part of Positron, and are made available here for easy access when building Positron.

Is Kallichore open source?

No. Its binaries are licensed for use in Positron, but its source code is not public.

Related Projects

Jupyter Server REST API

Jupyter Kernel Gateway

ARK, an R kernel