How to cross-compile simple tauri 2 project on x86-64 linux to armv7 linux with docker?

[qarmin]

I have some simple tauri 2 projects, that I want to cross-compile, to be able to run them on armv7 device, to check if it works, but I only found some outdated topics for tauri 1

#4528
https://v1.tauri.app/v1/guides/building/linux/#cross-compiling-tauri-applications-for-arm-based-devices

I have such dockerfile

FROM debian:bookworm-slim
ARG DEBIAN_FRONTEND=noninteractive

RUN apt update && \
    apt install -y \
        gnupg2 \
        ca-certificates \
        g++-arm-linux-gnueabihf \
        libc6-dev-armhf-cross \
        build-essential \
        pkg-config \
        curl \
        wget \
        file \
        python3 \
        python3-markdown \
        python3-mako

RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --target armv7-unknown-linux-gnueabihf
RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && apt-get update && apt-get install --assume-yes --no-install-recommends nodejs

RUN dpkg --add-architecture armhf
RUN apt update
RUN apt install libwebkit2gtk-4.1-dev:armhf \
      curl:armhf \
      wget:armhf \
      file:armhf \
      libxdo-dev:armhf \
      libssl-dev:armhf \
      libayatana-appindicator3-dev:armhf \
      librsvg2-dev:armhf \
      python3:armhf \
      build-essential:armhf \
      libsoup-3.0-dev:armhf

ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=arm-linux-gnueabihf-gcc \
    CC_armv7_unknown_linux_gnueabihf=arm-linux-gnueabihf-gcc \
    CXX_armv7_unknown_linux_gnueabihf=arm-linux-gnueabihf-g++ \
    BINDGEN_EXTRA_CLANG_ARGS_armv7_unknown_linux_gnueabihf="--sysroot=/usr/arm-linux-gnueabihf" \
    PKG_CONFIG_PATH="/usr/lib/arm-linux-gnueabihf/pkgconfig/" \
    PKG_CONFIG_ALLOW_CROSS=1 \
    PATH="/root/.cargo/bin:$PATH"
WORKDIR /app

# docker run  -it -v /home/rafal/test/tauri-app:/app -w /app armt /bin/bash
# cd src-tauri
# cargo build --target armv7-unknown-linux-gnueabihf

but due problem with dependencies, this shows such error

0.118 Reading package lists...                                                                                                                                                                                                                                                                                        
0.778 Building dependency tree...
0.956 Reading state information...
1.109 Some packages could not be installed. This may mean that you have
1.109 requested an impossible situation or if you are using the unstable
1.109 distribution that some required packages have not yet been created
1.109 or been moved out of Incoming.
1.109 The following information may help to resolve the situation:
1.109 
1.109 The following packages have unmet dependencies:
1.170  build-essential:armhf : Depends: make:armhf
1.170  dpkg-dev : Depends: binutils but it is not installable
1.170             Recommends: build-essential but it is not installable
1.171  gobject-introspection:armhf : Depends: python3-mako:armhf but it is not installable
1.171                                Depends: python3-markdown:armhf but it is not installable
1.176 E: Unable to correct problems, you have held broken packages.
------
Dockerfile:27
--------------------
  26 |     RUN apt update
  27 | >>> RUN apt install libwebkit2gtk-4.1-dev:armhf \
  28 | >>>       curl:armhf \
  29 | >>>       wget:armhf \
  30 | >>>       file:armhf \
  31 | >>>       libxdo-dev:armhf \
  32 | >>>       libssl-dev:armhf \
  33 | >>>       libayatana-appindicator3-dev:armhf \
  34 | >>>       librsvg2-dev:armhf \
  35 | >>>       python3:armhf \
  36 | >>>       build-essential:armhf \
  37 | >>>       libsoup-3.0-dev:armhf
  38 |     
--------------------

Looks that problematic is python3-mako:armhf package and I cannot install it via apt install python3-mako:armhf but I can via apt install python3-mako:all or apt install python3-mako, but this not fixes compilation problems

https://packages.debian.org/bookworm/python3-mako - is not available directly for armhf, but only for all

Is there any official docs, how to cross-compile tauri app to arm?

[FabianLars]

Is there any official docs, how to cross-compile tauri app to arm?

well, you linked the guide for it. afaik it still works, at least if you're okay with only a .deb and .rpm since the appimage tooling still doesn't support cross compilation.

here's the pr for the v2 port of that guide btw tauri-apps/tauri-docs#2981 - it's essentially the same with updated package versions.

[qarmin]

But this is very similar to what my Dockerfile does — and it still doesn’t work.
Ubuntu has issues with missing armhf packages, while Debian struggles with installing Python dependencies.

The problem I have with these kinds of tutorials is that they can be difficult to follow.
A Dockerfile, on the other hand, provides exact steps that I can follow easily — and it’s simple to check whether it still works and I think, that similar(working) dockerfile should be also included in docs.

[FabianLars]

Ubuntu has issues with missing armhf package

Which packages?

Debian struggles with installing Python dependencies.

Nobody i talked to so far about this had to install python stuff iirc so a docker image probably wouldn't have helped you here. If you only added those in response to some earlier error, please take another look at the docs you linked. It specifically only asks for the arm version of webkitgtk (appindicator is likely required too and we forgot about it). The rest of tauri's dependencies (the build tools) shouldn't require an arm version.

[qarmin]

FROM debian:bookworm-slim
ARG DEBIAN_FRONTEND=noninteractive

RUN apt update && \
    apt install -y \
        gnupg2 \
        ca-certificates \
        g++-arm-linux-gnueabihf \
        libc6-dev-armhf-cross \
        build-essential \
        pkg-config \
        curl \
        wget \
        file \
        python3 \
        python3-markdown \
        python3-mako

RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --target armv7-unknown-linux-gnueabihf
RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && apt-get update && apt-get install --assume-yes --no-install-recommends nodejs

RUN dpkg --add-architecture armhf
RUN apt update
RUN apt install libwebkit2gtk-4.1-dev:armhf

errors with

0.707 The following packages have unmet dependencies:
0.739  gobject-introspection:armhf : Depends: python3:armhf (< 3.12) but it is not going to be installed
0.739                                Depends: python3:armhf (>= 3.11~) but it is not going to be installed
0.739                                Depends: build-essential:armhf but it is not going to be installed
0.739                                Depends: python3-mako:armhf but it is not installable
0.739                                Depends: python3-markdown:armhf but it is not installable
0.745 E: Unable to correct problems, you have held broken packages.
------
WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
Dockerfile:24
--------------------
  22 |     RUN dpkg --add-architecture armhf
  23 |     RUN apt update
  24 | >>> RUN apt install libwebkit2gtk-4.1-dev:armhf

On ubuntu 22.04

FROM ubuntu:22.04
ARG DEBIAN_FRONTEND=noninteractive

RUN apt update && \
    apt install -y \
        gnupg2 \
        ca-certificates \
        g++-arm-linux-gnueabihf \
        libc6-dev-armhf-cross \
        build-essential \
        pkg-config \
        curl \
        wget \
        file \
        python3 \
        python3-markdown \
        python3-mako

RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --target armv7-unknown-linux-gnueabihf
RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && apt-get update && apt-get install --assume-yes --no-install-recommends nodejs

RUN dpkg --add-architecture armhf

RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy main restricted' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-updates main restricted' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy universe' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-updates universe' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy multiverse' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-updates multiverse' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-backports main restricted universe multiverse' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-security main restricted' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-security universe' >> /etc/apt/sources.list
RUN echo 'deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports jammy-security multiverse' >> /etc/apt/sources.list

RUN apt update
RUN apt install libwebkit2gtk-4.1-dev:armhf

fails with this message

5.946 Get:50 http://ports.ubuntu.com/ubuntu-ports jammy-security/multiverse arm64 Packages [26.5 kB]
5.947 Get:51 http://ports.ubuntu.com/ubuntu-ports jammy-security/universe arm64 Packages [1213 kB]
6.090 Fetched 58.2 MB in 6s (9729 kB/s)
6.090 Reading package lists...
7.210 E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy/restricted/binary-armhf/Packages  404  Not Found [IP: 91.189.91.81 80]
7.210 E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/jammy-security/multiverse/binary-armhf/Packages  404  Not Found [IP: 91.189.91.82 80]
7.210 E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy-updates/universe/binary-armhf/Packages  404  Not Found [IP: 91.189.91.81 80]
7.210 E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy-backports/main/binary-armhf/Packages  404  Not Found [IP: 91.189.91.81 80]
7.210 E: Some index files failed to download. They have been ignored, or old ones used instead.
------
WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
Dockerfile:36
--------------------
  34 |     
  35 |     
  36 | >>> RUN apt update
  37 |     RUN apt install libwebkit2gtk-4.1-dev:armhf
  38 |     

[FabianLars]

hmm okay the debian one is wild. i've seen a few mentions about all packages causing problems for use cases like ours but not many workarounds.

For the Ubuntu one i think you're missing this part from the guide:

Then, to prevent issues with the main packages, you have to add the correct main architecture to all other lines the file contained beforehand. For standard 64-bit systems you need to add [arch=amd64], the full file on Ubuntu 22.04 then looks similar to this:

[Stepisk]

Well, I managed to successfully build an application under armv7 based on an Ubuntu image. The main problem with loading sources was using the new .sources format, instead of .list. The new format has an optional Architectures parameter, which is not set by default. So adding new sources in the old format under a different architecture causes a conflict where the underlying package sources try to look for armhf packages.
I have attached a Dockerfile with which I was able to successfully build the Tauri application

FROM ubuntu:plucky

# Update package lists and install necessary tools and dependencies
RUN apt update && \
    apt install -y \
    build-essential \
    ca-certificates \
    curl \
    file \
    g++-arm-linux-gnueabihf \
    git \
    gnupg2 \
    libbz2-dev \
    libc6-dev-armhf-cross \
    pkg-config \
    python3 \
    python3-mako \
    python3-markdown \
    wget && \
    apt clean

# Install Rust with the ARMv7 target
RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --target armv7-unknown-linux-gnueabihf

# Install Node.js and pnpm
RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
    apt update && apt install -y --no-install-recommends nodejs && \
    apt clean && \
    npm install -g pnpm

# Add ARM architecture support
RUN dpkg --add-architecture armhf

# Copy custom APT sources configuration for Ubuntu and ARM packages
COPY <<EOF /etc/apt/sources.list.d/ubuntu.sources
Types: deb
URIs: http://archive.ubuntu.com/ubuntu/
Suites: plucky plucky-updates plucky-backports
Components: main universe restricted multiverse
Architectures: amd64
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

## Ubuntu security updates. Aside from URIs and Suites,
## this should mirror your choices in the previous section.
Types: deb
URIs: http://security.ubuntu.com/ubuntu/
Suites: plucky-security
Components: main universe restricted multiverse
Architectures: amd64
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

# Modernized from /etc/apt/sources.list
Types: deb
URIs: http://ports.ubuntu.com/ubuntu-ports/
Suites: plucky plucky-updates plucky-backports plucky-security
Components: main universe restricted multiverse
Architectures: armhf
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
EOF

# Install ARM-specific SSL and WebKit development libraries
RUN apt update && \
    apt install -y libssl-dev:armhf libwebkit2gtk-4.1-dev:armhf && \
    apt clean

# Set environment variables for cross-compilation
ENV PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabihf/pkgconfig:/usr/share/pkgconfig \
    PKG_CONFIG_ALLOW_CROSS=1 \
    PKG_CONFIG_SYSROOT_DIR=/usr/arm-linux-gnueabihf \
    PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 \
    CARGO_TARGET_ARMV7_UNKNOWN_LINUX_GNUEABIHF_LINKER=/usr/bin/arm-linux-gnueabihf-gcc

WORKDIR /app

# Comment: Instructions for running the container and building the Tauri app
# docker run  -it -v /home/<user>/projects/tauri-app:/app -w /app armt /bin/bash
# pnpm install
# pnpm tauri build --target armv7-unknown-linux-gnueabihf --bundles deb