musl toolchain misses rust build toolchain

[nikeee]

See nodejs/docker-node#2486

This leads to the official docker image not having Temporal on musl/alpine. Temporal is just skipped if the build environment doesn't have rustc/cargo in its path.

[MikeMcC399]

PR #228 resolved this issue for amd64

[MikeMcC399]

Node.js 26.0.0 released with the announcement:

Temporal API

The Temporal API is now enabled by default in Node.js 26. Temporal is a modern date/time API for JavaScript
that provides a more robust and feature-rich alternative to the legacy Date object.

linux-arm64-musl should follow the default for Node.js >=26 and also support the Temporal API.

The merged PR #228 addressed:

• recipes/musl/Dockerfile for amd64

It did not address:

• recipes/arm64-musl for arm64

Suggestion

Add rustc & cargo according to Building Node.js with Temporal support also to:

• recipes/arm64-musl for arm64

Related

• Pull Alpine/aarch64 tarball from unofficial builds as we do for Alpine/x64 docker-node#2475
• Temporal API not available in Alpine v26 images docker-node#2486
• feat: Node.js Alpine arm64 Unofficial Builds docker-node#2476
• Add rustc toolchain to alpine images docker-node#2488

cc: @sxa @nschonni

[sxa]

It did not address: recipes/arm64-musl for arm64

Noting that nodejs/docker-node#2488 (mentioned in the related section in the previous comment) would be a solution for this.

[MikeMcC399]

It did not address: recipes/arm64-musl for arm64

Noting that nodejs/docker-node#2488 (mentioned in the related section in the previous comment) would be a solution for this.

That is only true for the docker-node consumer, not for other independent consumers of linux-arm64-musl. For docker-node I think we need to come to a consensus about which method is preferred and then work together on getting this implemented:

• Add rustc toolchain to alpine images docker-node#2488 adds rustc / cargo into the Dockerfile and then cross-compiles for arm64
• feat: Node.js Alpine arm64 Unofficial Builds docker-node#2476 pulls linux-arm64-musl and builds without cross-compiling using separate GitHub Actions Ubuntu runners for amd64 and arm64

That discussion is better suited for the https://github.com/nodejs/docker-node repo though, so I'll duplicate it there.

[awbx]

PR for the arm64 side: #234

[MikeMcC399]

For the downstream nodejs/docker-node repo, builds of node:alpine images for Node.js 26 now have Temporal support. nodejs/docker-node#2488 added a Rust toolchain to the Alpine Dockerfiles in that repo.

The current setup in nodejs/docker-node does not need any further changes in unofficial-builds.

Possibly, other consumers of builds from this repo may benefit from building with a Rust toolchain, however the recipes don't allow for differences in Node.js versions, so if a Rust toolchain is added it would also be applied to Node.js <=24 versions that are incompatible with Temporal, since they don't meet the minimum V8 requirements for Temporal.

[sxa]

if a Rust toolchain is added it would also be applied to Node.js <=24 versions that are incompatible with Temporal, since they don't meet the minimum V8 requirements for Temporal.

That's not a problem - we don't use separate build containers for each node version so it just wouldn't get used pre-node26.

[MikeMcC399]

That's not a problem - we don't use separate build containers for each node version so it just wouldn't get used pre-node26.

I only meant that it's an extra overhead when it's not used. Sorry I wasn't very clear in what I wrote!

alpine:3.23 is 13MB uncompressed locally
apk add rustc cargo takes it up to 883MB

Incremental it may only be ~400MiB

OK: 304 MiB in 95 packages
/ # apk add rust cargo
(1/5) Installing libxml2 (2.13.9-r0)
(2/5) Installing llvm20-libs (20.1.8-r0)
(3/5) Installing scudo-malloc (20.1.8-r0)
(4/5) Installing rust (1.87.0-r1)
(5/5) Installing cargo (1.87.0-r1)
Executing busybox-1.37.0-r20.trigger
OK: 698 MiB in 100 packages

[nikeee]

I only meant that it's an extra overhead when it's not used

(disregard this comment if you were not talking about the Dockerfiles in docker-node):
In docker-node, rust and cargo are installed as a virtual package in apk add --no-cache --virtual .build-deps-full, alongside the gcc toolchain.
The entire build happens in one RUN command and runs apk del .build-deps-full to remove all build tools in the same step. So the final image size isn't impacted at all by adding rust and cargo. The only thing thats different is that the image build takes a couple of seconds longer due to the installation of rust/cargo. But they don't remain in the final image.

[MikeMcC399]

The needs of node Docker Alpine builds in https://github.com/nodejs/docker-node are currently already met (see nodejs/docker-node > Dockerfile-alpine.template):

• node Docker Alpine Linux/amd64 builds uses https://unofficial-builds.nodejs.org/download/release/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64-musl.tar.xz which is built with rust & cargo installed:

unofficial-builds/recipes/musl/Dockerfile

Lines 1 to 25 in 2708d03

	FROM alpine:3.22
	ARG GID=1000
	ARG UID=1000
	RUN addgroup -g $GID node \
	&& adduser -u $UID -G node -s /bin/sh -D node
	RUN apk add --no-cache \
	libstdc++ \
	&& apk add --no-cache --virtual .build-deps \
	bash \
	binutils-gold \
	curl \
	g++ \
	gcc \
	gnupg \
	libgcc \
	linux-headers \
	make \
	python3 \
	ccache \
	xz \
	rust \
	cargo

• node Docker Alpine Linux/arm64 builds do not rely on https://unofficial-builds.nodejs.org and instead build from source with rust & cargo installed, as shown in nodejs/docker-node > Dockerfile-alpine.template:

---

Future node Docker Alpine Linux/amd64 image builds would transition to using musl builds published to https://nodejs.org/download/release/ if the approved PR nodejs/node#63737 to promote Alpine/x64 to Tier 2 is merged. Preparation for this is an open action item (see also Build WG minutes https://hackmd.io/@openjs-nodejs/BJNLz8jfGg 2026-07-02).

In that case node Docker Alpine image builds would no longer depend on https://unofficial-builds.nodejs.org.