Zenoh Plugin Project for Unity

This is experimental Zenoh Plugin for Unity. This plugin utilizes zenoh-c with csbindgen generated binding code.

Zenoh version: 1.9.0

Architecture: 3-layer wrapper design

This plugin provides three layers of abstraction. Users typically write code against the HighLevel layer.

Layer	Namespace	Role
Plugins	ZenohNative (P/Invoke)	csbindgen auto-generated native bindings. Not hand-edited.
Bindings	Zenoh.Bindings (ZOwned* / ZLoaned* / Z*Options)	Memory-safe 1:1 C# projection of zenoh-c. Preserves native ownership semantics (Owned/Loaned/Take). Returns ZResult, never throws.
HighLevel	Zenoh.HighLevel (Session / Publisher / Subscriber / Queryable / …)	Ergonomic API for end-users. Exceptions on failure (ZenohException), byte[]/string payloads, POCO option classes. Hides the Owned/Loaned/Take machinery.

Covered use cases (HighLevel)

• Session: Open / Close
• Pub/Sub: Publisher (Put / PutZeroCopy), Subscriber (callback-based)
• Query/Reply: Queryable (Reply / ReplyErr / ReplyDel), Session.Get (with CancellationToken support)
• Key Expression: Parse / TryParse
• Config: Default / FromJsonString / FromFile

Features not yet covered by HighLevel (e.g. Querier, Liveliness, SharedMemory) are also not yet implemented in the Bindings layer. They will be added as needed.

AI-assisted code generation

Each layer has a generation rules document that defines naming conventions, ownership patterns, error handling, and file layout:

• Runtime/Bindings/00_bindings-generation-rules.md — rules for projecting ZenohNative.g.cs into Bindings classes
• Runtime/HighLevel/00_highlevel_wrapper_generation_rules.md — rules for wrapping Bindings types into the HighLevel API

These rule documents are designed so that an AI coding assistant can generate new wrappers mechanically. Given a rule document and a target Bindings type, the assistant can produce a conformant HighLevel wrapper with the correct ownership handling, Dispose patterns, and API shape. Implementation plans (e.g. Specs/query-reply-highlevel-plan.md) reference these rules and serve as input for AI-driven implementation.

Platforms

Confirmed on Unity 2022.3.x

Build target platform:

• windows x86-64
• MacOS Apple Silicon
• Android arm64
• iOS (experimental)

Note for Android

• set Player Settings as follows.
  • enable IL2CPP scripting backend and select arm64 architecture.
  • set internet access as Required

How to install this package

Input this url to the Package Manager's 'Add package from Git URL...' menu.

https://github.com/mhama/zenoh-unity-plugin.git?path=Assets/ZenohPackage

About samples

Sample scenes are located under Assets/ZenohSampleScenes/.

HighLevel API samples (HighLevelWrapperTests/)

• SimplePubSubHighLevelTest — Publish/Subscribe using the HighLevel API
• QueryableReplyHighLevelTest — Queryable (server side) that replies to queries
• QueryGetHighLevelTest — Session.Get (client side) that sends queries and receives replies
• CameraPubSubHighLevelSample — Camera image Pub/Sub using the HighLevel API

Bindings API samples (BindingTests/)

• QueryableReplyBindingTest / QueryGetBindingTest — Query/Reply using the Bindings layer directly

Legacy wrapper samples (LegacyWrapperTests/)

• SimplePubSubTest — Pub/Sub using legacy wrappers (not recommended for new code)
• CameraPublisherTest / CameraReceiverTest — Camera image Pub/Sub using legacy wrappers

How to make DLL / ZenohNative.g.cs for each platforms

binding code can be generated with a branch of zenoh-c-cs project. This project is a fork of zenoh-c with capability to output csharp binding code using csbindgen.

clone repo

git clone https://github.com/mhama/zenoh-c-cs
git checkout 20260511-csbindgen-1.9.0

For MacOS (Apple Silicon) (non-cross-compiling)

This is the case for building on MacOS (for MacOS).

# remove./build folder if exist
mkdir -p ./build && cd ./build
cmake -DZENOHC_BUILD_WITH_UNSTABLE_API=true -DZENOHC_BUILD_WITH_SHARED_MEMORY=true ..  -GNinja
cmake --build . --config Release

use target/release/libzenohc.dylib, target/ZenohNative.g.cs

For Windows (cross-compiling on Mac OS)

prepare

brew install mingw-w64
rustup target add x86_64-pc-windows-gnu

build

# remove./build folder if exist
mkdir -p ./build && cd ./build
cmake -DCMAKE_TOOLCHAIN_FILE="../ci/toolchains/TC-x86_64-pc-windows-gnu.cmake" -DZENOHC_BUILD_WITH_SHARED_MEMORY=ON -DZENOHC_BUILD_WITH_UNSTABLE_API=ON ..
cmake --build . --config Release

use target/x86_64-pc-windows-gnu/release/zenohc.dll, target/ZenohNative.g.cs

For Android arm64 (cross-compiling on Mac OS)

prepare install Android SDK and NDK.

rustup target add aarch64-linux-android

modify ci/toolchains/TC-aarch64-linux-android.cmake

set(CMAKE_ANDROID_NDK /PATH/TO/ANDROID/NDK) # fix path

build

# remove./build folder if exist
mkdir -p ./build && cd ./build
cmake -DCMAKE_TOOLCHAIN_FILE="../ci/toolchains/TC-aarch64-linux-android.cmake" -DZENOHC_BUILD_WITH_UNSTABLE_API=ON ..
cmake --build . --config Release

(Notice that shared memory apis are not supported on Android platform.)

use target/aarch64-linux-android/release/libzenohc.so, target/ZenohNative.g.cs

if there's error on building ring or get failed to find tool "aarch64-linux-android-clang"

I experienced an error here at building ring package. Here's the log:

warning: ring@0.17.13: Compiler family detection failed due to error: ToolNotFound: failed to find tool "aarch64-linux-android-clang": No such file or directory (os error 2)
warning: ring@0.17.13: Compiler family detection failed due to error: ToolNotFound: failed to find tool "aarch64-linux-android-clang": No such file or directory (os error 2)
error: failed to run custom build command for ring v0.17.13

Or if you get this error

error occurred in cc-rs: failed to find tool "aarch64-linux-android-clang": No such file or directory (os error 2)

Here's the workaround:

android_ndk=/YOUR-NDK-PATH/toolchains/llvm/prebuilt/darwin-x86_64/bin
export CC_aarch64_linux_android=$android_ndk/aarch64-linux-android21-clang
export AR_aarch64_linux_android=$android_ndk/llvm-ar
export CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER=$android_ndk/aarch64-linux-android21-clang

Then build again.

For iOS (cross-compiling on Mac OS) (experimental)

prepare

rustup target add aarch64-apple-ios

build

cargo build --release --no-default-features --features=transport_tcp,transport_tls,unstable --target=aarch64-apple-ios

use target/aarch64-apple-ios/release/libzenohc.a, target/ZenohNative.g.cs