🔌 Reactor

Reactor provides two sibling packages in one repository, with no python/typescript subpackage folders:

• datalayer_reactor (PyPI distribution, imported as reactor): FastAPI + pluggy plugin reactor for modular and SaaS-style extensibility.
• @datalayer/reactor (TypeScript): Extension runtime with a framework-agnostic core and separate React integration.

Why Reactor

This project targets a full extension reactor, not only hook callbacks:

• Platform architecture with lifecycle phases and dependency graph
• Plugin marketplace metadata and discovery primitives
• Third-party ecosystem support through explicit manifest contracts
• Dynamic feature loading and runtime enable/disable
• Modular app concerns: interdependencies, lifecycle management, compatibility checks
• SaaS extensibility primitives: tenant-specific plugin activation, sandboxed execution, versioned compatibility

Repository Layout

• src/: TypeScript package source for @datalayer/reactor
• reactor/: Python package source
• examples/frontend/: frontend-only React + Primer UI demo
• examples/frontend-backend/: combined React + Python demo

TypeScript Package: @datalayer/reactor

Design

The TypeScript runtime implements:

• defineExtension and configExtension
• dependencies, peerDependencies, conflictsWith
• ordered phases: init -> build -> register -> afterRegistration
• runtime lifecycle control: start, stop, enable, disable
• signal primitives for reactive extension outputs:
  • signal, computed, effect, batch, untracked
  • namedSignals, watchedSignal

Core vs React split

• Core runtime exports from @datalayer/reactor
• React bindings export from @datalayer/reactor/react

React bindings include:

• useReactor: register the reactor in the zustand store and manage its lifecycle
• ReactorSlot: render plugin-provided components by named slot
• useReactorPlatform: reactor access for runtime toggles

Build

npm install
npm run build

Minimal TypeScript usage

import { buildReactorFromExtensions, defineExtension } from '@datalayer/reactor';

const DemoExtension = defineExtension({
	name: '@demo/core',
	build() {
		return { message: 'hello' };
	},
});

const reactor = buildReactorFromExtensions([DemoExtension]);
reactor.start();

Python Package: datalayer_reactor

Capabilities

• Pluggy-powered plugin registration (register_plugin)
• Compatibility and dependency checks via PluginManifest
• Runtime enable/disable globally and by tenant
• Marketplace publication/listing (PluginMarketplace)
• Sandboxed execution option for plugin calls
• FastAPI control plane with plugin/tenant endpoints

Install and run

python -m venv .venv
source .venv/bin/activate
pip install -e .
python -m reactor

API app endpoints

• GET /plugins
• POST /plugins/{plugin_name}/toggle
• POST /tenants/plugins/{plugin_name}/toggle
• GET /tenants/{tenant_id}/features
• GET /tenants/{tenant_id}/routes
• GET /marketplace

Minimal Python usage

from reactor import PluginManifest, PluginCompatibility, PluginPlatform

reactor = PluginPlatform()
reactor.register_plugin(
		PluginManifest(
				name="greeting-plugin",
				version="1.0.0",
				compatibility=PluginCompatibility(api_version="v1"),
		),
		plugin_impl=object(),
)