Examples demonstrating the WebAssembly Component Model using rules_wasm_component with Bazel.

• Bazel 7.0+
• Wasmtime (for running components)
• For YOLO: Wasmtime compiled with ONNX backend support

# Build all examples
bazel build //...

# Build specific example
bazel build //rust:hello_rust
bazel build //rust:yolo_inference_release

# Hello world
wasmtime bazel-bin/rust/hello_rust.runfiles/_main/rust/hello_rust_host.wasm

# Calculator
wasmtime bazel-bin/rust/calculator.runfiles/_main/rust/calculator_host.wasm 8 + 8

# DateTime
wasmtime bazel-bin/rust/datetime.runfiles/_main/rust/datetime_host.wasm

Requires ONNX model (see models/README.md):

# Download model
curl -L -o models/yolov8n.onnx \
  https://github.com/ultralytics/assets/releases/download/v0.0.0/yolov8n.onnx
mkdir -p models/yolov8n && ln -sf ../yolov8n.onnx models/yolov8n/model.onnx

# Run detection
wasmtime run --dir . -S cli -S nn -S nn-graph=onnx::./models/yolov8n \
  bazel-out/darwin_arm64-fastbuild-ST-*/bin/rust/yolo_inference_wasm_lib_release_wasm_base.wasm \
  ./bus.jpg

.
├── c/                    # C hello world component
├── cpp/                  # C++ hello world component
├── rust/                 # Rust components
│   ├── src/
│   │   ├── main.rs           # hello_rust
│   │   ├── calculator.rs     # calculator
│   │   ├── datetime.rs       # datetime
│   │   └── yolo_inference.rs # YOLO detection logic
│   └── wit/yolo.wit
├── rust_p3/              # Rust P3 async components + composed CLI
│   ├── src/
│   │   ├── text_processor.rs  # text analysis & transformation
│   │   ├── concurrent.rs      # math computations (fib, prime, collatz)
│   │   └── cli_runner.rs      # CLI runner (imports P3 interfaces)
│   └── wit/
│       ├── text_processor.wit
│       ├── concurrent.wit
│       └── cli_runner.wit     # imports P3 + WASI CLI interfaces
├── models/               # ONNX models (download separately)
├── MODULE.bazel
└── BUILD.bazel

Export custom interfaces that can be composed with other components:

interface greeter {
    greet: func() -> string;
}

world hello-c {
    export greeter;
}

Export wasi:cli/run for direct execution with Wasmtime.

• CI (ci.yml): Builds all components on Linux and macOS, runs Rust CLI tests
• Release (release.yml): Creates signed releases with provenance attestation

The rust_p3/ directory demonstrates WASI Preview 3 async components. Setting wasi_version = "p3" on a rust_wasm_component_bindgen target passes --async to wit-bindgen, making all exported trait methods async fn. This enables cooperative concurrency within the Component Model.

Exports two async interfaces:

• analyzer — analyze() returns stats (word count, unique words, avg length), word_frequencies() returns sorted frequency table, search_positions() finds pattern occurrences
• transformer — transform() for case/reverse/title-case, caesar_cipher() for shift ciphers, replace_all() for substitution

Exports async mathematical functions designed for concurrent dispatch:

• fibonacci(n), factorial(n), is_prime(n), collatz_steps(n)
• compute_batch(numbers) — runs fibonacci, prime check, and collatz on every input

A CLI runner component composed with the P3 libraries via wac_plug. Demonstrates the full component model workflow: build library components, build a CLI runner that imports their interfaces, compose with wac into a single runnable binary.

# Build the composed CLI
bazel build //rust_p3:p3_cli

# Run (requires wasmtime with component-model-async support)
wasmtime run -W component-model-async=y bazel-bin/rust_p3/p3_cli.wasm analyze "the quick brown fox"
wasmtime run -W component-model-async=y bazel-bin/rust_p3/p3_cli.wasm fibonacci 10
wasmtime run -W component-model-async=y bazel-bin/rust_p3/p3_cli.wasm transform uppercase "hello world"
wasmtime run -W component-model-async=y bazel-bin/rust_p3/p3_cli.wasm batch 5 10 15

See rust_p3/src/text_processor.rs and rust_p3/src/concurrent.rs for the async implementation pattern using #[cfg(target_arch)] gates.

Apache-2.0