Rust Plugin System Playground

This repository is a course-like workspace for exploring runtime-loadable plugins in Rust across multiple host surfaces:

• CLI
• TUI
• Desktop GUI with egui/eframe
• Desktop GUI with Iced
• Desktop GUI with Dioxus Desktop
• Web-facing host
• Service/API host

It compares three plugin architecture tracks:

1. Native dynamic libraries for direct runtime loading
2. ABI-stable native plugins for more durable contracts
3. WASM sandboxed plugins for stronger isolation and portability

The goal is not just to show code that works, but to make the trade-offs clear enough that the repository can be used as a public learning resource and a practical snippet zoo.

Repository map

• crates/ - shared contracts, loaders, runtimes, SDKs, and host support crates
• hosts/ - host applications that load plugins at runtime
• plugins/ - example plugin implementations across difficulty levels
• examples/ - packaging, distribution, and bundle layout assets for local release workflows
• docs/ - course material, reference docs, comparisons, and tutorials

Current focus

The current implementation slice establishes:

• a Cargo workspace
• a shared JSON-based plugin protocol
• a native runtime-loading path
• multiple host apps that consume the same plugin model
• a documentation backbone for the broader course experience
• a practical native plugin catalog that now includes:
  • foundation examples: hello-world, logger, formatter, transformer, command-pack, ui-panel
  • Phase 2 examples: config-provider, filesystem-tools, data-pipeline, metrics-observer, service-hooks, tui-tools
• a Phase 3 host comparison pass with richer host surfaces built on shared host-core helpers such as default_payload_text() and supports_host()

Rich host surfaces at a glance

Phase 3 turns the host apps into a real comparison set instead of a binary list:

• host-tui - keyboard-first terminal host with separate plugin panes, action panes, inline payload editing, templates, and output review
• host-egui - inspector/dashboard host for browsing manifest metadata, action templates, payload editing, and output panels
• host-iced - explicit state/update desktop host where plugin selection, action selection, template loading, and invocation are part of the app flow
• host-dioxus-desktop - reactive desktop action studio with plugin/action selection, payload editing, invocation, and output panels; the crate uses an explicit [[bin]] target with autobins = false
• host-web - browser-facing catalog with manifest badges, action browser, payload composer, and result cards for human-guided comparison
• host-service - automation-first HTTP API with discovery, examples, detail endpoints, and POST /plugins/{plugin_id}/actions/{action_id}/invoke as the canonical invoke path

If you want the guided comparison, start with docs/hosts/host-matrix.md and docs/hosts/surface-comparison.md.

Host × Architecture Matrix

Host	Native JSON	ABI-Stable	WASM	UI Type
host-cli	✅	✅	✅	Terminal
host-tui	✅	—	—	Terminal (Ratatui)
host-egui	✅	—	—	Desktop (egui)
host-iced	✅	—	—	Desktop (Iced)
host-dioxus-desktop	✅	—	—	Desktop (Dioxus)
host-web	✅	—	—	Browser (Axum SSR)
host-service	✅	—	—	API (Axum JSON)

Only host-cli loads all three plugin tracks directly. The other hosts use host-core::Playground, which loads native JSON plugins via plugin-loader.

Plugin Catalog

Plugin	Architecture	Skill Level	Actions
hello-world	Native JSON	Basic	1
logger	Native JSON	Basic	1
formatter	Native JSON	Basic	1
transformer	Native JSON	Intermediate	1
command-pack	Native JSON	Intermediate	1
ui-panel	Native JSON	Intermediate	1
config-provider	Native JSON	Intermediate	3
filesystem-tools	Native JSON	Intermediate	3
data-pipeline	Native JSON	Intermediate	3
metrics-observer	Native JSON	Intermediate	2
service-hooks	Native JSON	Intermediate	2
tui-tools	Native JSON	Intermediate	2
abi-stable-greeter	ABI-Stable	Advanced	2
abi-stable-command-pack	ABI-Stable	Advanced	1
wasm-sandboxed	WASM	Advanced	3
web-widget	WASM	Advanced	3

Quickstart

cargo build --workspace
cargo run -p host-cli -- list
cargo run -p host-cli -- run hello-world greet '{"name":"Rustacean"}'
cargo run -p host-cli -- run config-provider merge-layers '{"defaults":{"service":{"port":8080}},"environment":{"service":{"port":8081}},"overrides":{"service":{"host":"127.0.0.1"}}}'
cargo run -p host-cli -- run data-pipeline summarize-field '{"records":[{"duration":12.5},{"duration":7.5}],"field":"duration"}'
cargo run -p host-cli -- run abi-stable-greeter greet '{"name":"Rustacean"}'
cargo run -p host-cli -- run abi-stable-greeter plan-upgrade '{"from_host":"0.1.0","to_host":"0.2.0","consumer":"host-cli"}'
cargo run -p host-cli -- inspect service-hooks
cargo run -p host-cli -- run service-hooks preview-delivery '{"service":"billing","event":"deploy.succeeded","attempt":2}'
cargo run -p host-cli -- run wasm-sandboxed run-demo '{"note":"sandbox"}'
cargo run -p host-cli -- run web-widget render-widget '{"theme":"dark","variant":"incident"}'

Then compare richer hosts:

cargo run -p host-tui
cargo run -p host-egui
cargo run -p host-iced
cargo run -p host-dioxus-desktop
cargo run -p host-web      # http://127.0.0.1:4000
cargo run -p host-service  # http://127.0.0.1:5000

Start in docs/overview/index.md, then follow:

• docs/getting-started/quickstart.md
• docs/hosts/host-matrix.md
• docs/hosts/surface-comparison.md
• docs/plugins/native-json-catalog.md
• docs/snippets/cli-recipes.md

Publish new versions

Make sure that the token from Kellnr is available in the environment as CARGO_REGISTRIES_DZWEI_REGISTRY_TOKEN.

export CARGO_REGISTRIES_DZWEI_REGISTRY_TOKEN=yourtokentokellnr
LEVEL=$(./scripts/detect-release-level.sh)
cargo release "$LEVEL" --execute --no-publish
./scripts/publish-shared-crates.sh

License

This project is licensed under MIT.