Build ONNX Runtime for Web

There are 2 steps to build ONNX Runtime Web:

• build ONNX Runtime for WebAssembly
  • or skip and download a pre-built artifacts
• build onnxruntime-web (NPM package)

Contents

• Build ONNX Runtime for WebAssembly
• Build onnxruntime-web (NPM package)

Build ONNX Runtime for WebAssembly

Prerequisites

• Checkout the source tree:

  git clone --recursive https://github.com/Microsoft/onnxruntime
  cd onnxruntime
  

• Install cmake-3.18 or higher.

• Install Node.js (14.0+)

  • (Optional) Use nvm (Windows / Mac/Linux) to install Node.js
• Python (2.7 or 3.6+): https://www.python.org/downloads/
  • python should be added to the PATH environment variable

Build Instructions

in <ORT_ROOT>/, run one of the following commands to build WebAssembly:

# In windows, use 'build' to replace './build.sh'

# The following command build debug.
./build.sh --build_wasm

# The following command build debug with debug info.
./build.sh --build_wasm --skip_tests --enable_wasm_debug_info

# The following command build release.
./build.sh --config Release --build_wasm --skip_tests --disable_wasm_exception_catching --disable_rtti

ONNX Runtime WebAssembly can be built with or without multi-thread/SIMD support, specified by appending the following flags.

To get all build artifacts of ONNX Runtime WebAssembly, it needs 4 times of build with the combinations of ON/OFF of the 2 flags. A full list of build artifacts are as below:

Minimal Build Support

ONNX Runtime WebAssembly can be built with flag --minimal_build. This will generate smaller artifacts and also have a less runtime memory usage. An ORT format model is required. A detailed instruction will come soon. See also ORT format Conversion.

FAQ

Q: unittest fails on Release build.

A: unittest requires C++ exceptions to work properly. However, for performance concern, we disabled exception catching in emscripten. So please specify --skip_tests in Release build.

Q: unittest fails on Debug build with debug info.

A: building with debug info will generate very huge artifacts (>1GB for unittest) and failed to load in Node.js. So please specify --skip_tests in build with debug info.

Build onnxruntime-web (NPM package)

Prerequisites

• Install Node.js (14.0+)

  • (Optional) Use nvm (Windows/Mac/Linux) to install Node.js

• Chrome or Edge browser for running tests.

Build Instructions

1. Install NPM packages

   1. in <ORT_ROOT>/js/, run npm ci.
   2. in <ORT_ROOT>/js/common/, run npm ci.
   3. in <ORT_ROOT>/js/web/, run npm ci.

2. Prepare ONNX Runtime WebAssembly artifacts.

   You can either use the prebuilt artifacts or build it by yourself.

   • Setup by script.

     In <ORT_ROOT>/js/web/, run npm run pull:wasm to pull WebAssembly artifacts for latest master branch from CI pipeline.

   • Download artifacts from pipeline manually.

     you can download prebuilt WebAssembly artifacts from Windows WebAssembly CI Pipeline. Select a build, download artifact “Release_wasm” and unzip. See instructions below to put files into destination folders.

   • Build WebAssembly artifacts.

     1. Build ONNX Runtime WebAssembly

        Follow instructions above for building ONNX Runtime WebAssembly.

     2. Copy following files from build output folder to <ORT_ROOT>/js/web/dist/ (create the folder if it does not exist):

        • ort-wasm.wasm
        • ort-wasm-threaded.wasm (build with flag ‘–enable_wasm_threads’)
        • ort-wasm-simd.wasm (build with flag ‘–enable_wasm_simd’)
        • ort-wasm-simd-threaded.wasm (build with flags ‘–enable_wasm_threads –enable_wasm_simd’)

     3. Copy following files from build output folder to <ORT_ROOT>/js/web/lib/wasm/binding/:

        • ort-wasm.js
        • ort-wasm-threaded.js (build with flag ‘–enable_wasm_threads’)
        • ort-wasm-threaded.worker.js (build with flag ‘–enable_wasm_threads’)

3. Use following command in folder <ORT_ROOT>/js/web to build:

   npm run build