doc: document approach for building wasm in deps · nodejs/node@6e7e9a1
@@ -145,6 +145,48 @@ can be added as a non-externalizable dependency. In this case
145145simply add the path to the JavaScript file in the `deps_files`
146146list in the `node.gyp` file.
147147148+## Common approach for dependencies with WASM components
149+150+WASM components within dependencies are most often built
151+outside of the regular Node.js `make build` step. They also
152+require different tools.
153+154+It is important that the tools and their versions used to build
155+WASM components shipped within Node.js are well documented and
156+be available if needed to rebuild/update older Node.js versions.
157+158+In order to minimize the different number of tools and versions
159+used to build WASM components and to document and ensure future
160+availability, the project builds and maintains a common
161+[wasm-builder](https://github.com/nodejs/wasm-builder) container
162+that should be use to build WASM components in Node.js
163+dependencies.
164+165+The container provides a durable copy of the versions of the tools
166+used for a specific build which are under the control of the Node.js
167+project. In addition, the tools and verions are documented through metadata
168+within the container in the `/home/node/metadata directory`.
169+170+The available tools can be found by looking at the current version of the
171+[Dockerfile](https://github.com/nodejs/wasm-builder/blob/main/container-build-info/Dockerfile)
172+used to create the container.
173+174+If additional WASM tool are needed beyond those available in the
175+container, additions should be PR'd into the wasm-builder container.
176+177+Examples of using the container include:
178+179+* [build/wasm.js](https://github.com/nodejs/undici/blob/main/build/wasm.js) from undici
180+* [tools/build-wasm.js](https://github.com/nodejs/amaro/blob/main/tools/build-wasm.js) from amaro
181+182+In addition to using the container to build WASM components, the goal is also
183+for the WASM components and final files that are shipped with Node.js to be
184+built by the [dep-updaters](https://github.com/nodejs/node/tree/main/tools/dep_updaters)
185+that are run on a regular basis and that they use only the files available in the Node.js
186+repo for the dependency. For example, being able to rebuild the WASM and files that
187+we ship in Node.js using only the files in
188+[../deps/undici](https://github.com/nodejs/node/tree/main/deps/undici).
189+148190## Updating dependencies
149191150192Most dependencies are automatically updated by