Unable to build release via Balena Cloud

[mbh-dev]

Hi,

When trying to deploy this repo via Balena Cloud it fails to build the release and provides the following error:

[Info] Starting build for train-departure-display, user ******
[Info] Dashboard link: https://dashboard.balena-cloud.com/apps/******/devices
[Info] Building on ******
[Info] No suitable previous release for caching, skipping cache pull
[Info] Starting to build main
[Success] Successfully built service main
[Info] Uploading images
[Success] Successfully uploaded images
[Error] Some services failed to build:
[Error] Service: main
[Error] Error: The command '/bin/sh -c pip install --no-cache-dir -r requirements.txt' returned a non-zero code: 1
[Info] Built on ******
[Error] Not deploying release.

---

Step 1/12 : FROM python:3.12-alpine3.22 as builder
---> f4cb366587be
Step 2/12 : RUN apk add --no-cache freetype-dev libjpeg-turbo-dev gcc musl-dev linux-headers
Using cache
---> e823acc177b4
Step 3/12 : WORKDIR /usr/src/app
Using cache
---> d7b312c92caf
Step 4/12 : COPY requirements.txt .
Using cache
---> 1d9b84dcc4fe
Step 5/12 : RUN pip install --no-cache-dir -r requirements.txt
---> Running in 17baf3ed26eb
Collecting luma.oled (from -r requirements.txt (line 1))
Downloading luma_oled-3.15.0-py3-none-any.whl.metadata (27 kB)
Collecting timeloop (from -r requirements.txt (line 2))
Downloading timeloop-1.0.2.tar.gz (2.9 kB)
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'done'
Preparing metadata (pyproject.toml): started
Preparing metadata (pyproject.toml): finished with status 'done'
Collecting requests (from -r requirements.txt (line 3))
Downloading requests-2.34.0-py3-none-any.whl.metadata (4.8 kB)
Collecting xmltodict (from -r requirements.txt (line 4))
Downloading xmltodict-1.0.4-py3-none-any.whl.metadata (14 kB)
Collecting defusedxml (from -r requirements.txt (line 5))
Downloading defusedxml-0.7.1-py2.py3-none-any.whl.metadata (32 kB)
Collecting RPi.GPIO (from -r requirements.txt (line 6))
Downloading RPi.GPIO-0.7.1.tar.gz (29 kB)
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'done'
Preparing metadata (pyproject.toml): started
Preparing metadata (pyproject.toml): finished with status 'done'
Collecting spidev (from -r requirements.txt (line 7))
Downloading spidev-3.8.tar.gz (13 kB)
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'done'
Preparing metadata (pyproject.toml): started
Preparing metadata (pyproject.toml): finished with status 'done'
Collecting cbor2>=5.8.0 (from -r requirements.txt (line 8))
Downloading cbor2-6.0.1.tar.gz (84 kB)
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'done'
Preparing metadata (pyproject.toml): started
Preparing metadata (pyproject.toml): finished with status 'done'
Collecting urllib3>=2.6.3 (from -r requirements.txt (line 9))
Downloading urllib3-2.7.0-py3-none-any.whl.metadata (6.9 kB)
Collecting pillow>=10.3.0 (from -r requirements.txt (line 10))
Downloading pillow-12.2.0.tar.gz (47.0 MB)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 47.0/47.0 MB 51.5 MB/s eta 0:00:00
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'done'
Preparing metadata (pyproject.toml): started
Preparing metadata (pyproject.toml): finished with status 'done'
Collecting luma.core>=2.4.1 (from luma.oled->-r requirements.txt (line 1))
Downloading luma_core-2.5.3-py3-none-any.whl.metadata (30 kB)
Collecting charset_normalizer<4,>=2 (from requests->-r requirements.txt (line 3))
Downloading charset_normalizer-3.4.7-py3-none-any.whl.metadata (40 kB)
Collecting idna<4,>=2.5 (from requests->-r requirements.txt (line 3))
Downloading idna-3.14-py3-none-any.whl.metadata (8.0 kB)
Collecting certifi>=2023.5.7 (from requests->-r requirements.txt (line 3))
Downloading certifi-2026.4.22-py3-none-any.whl.metadata (2.5 kB)
Collecting smbus2 (from luma.core>=2.4.1->luma.oled->-r requirements.txt (line 1))
Downloading smbus2-0.6.1-py2.py3-none-any.whl.metadata (7.1 kB)
Downloading luma_oled-3.15.0-py3-none-any.whl (33 kB)
Downloading requests-2.34.0-py3-none-any.whl (73 kB)
Downloading xmltodict-1.0.4-py3-none-any.whl (13 kB)
Downloading defusedxml-0.7.1-py2.py3-none-any.whl (25 kB)
Downloading urllib3-2.7.0-py3-none-any.whl (131 kB)
Downloading certifi-2026.4.22-py3-none-any.whl (135 kB)
Downloading charset_normalizer-3.4.7-py3-none-any.whl (61 kB)
Downloading idna-3.14-py3-none-any.whl (72 kB)
Downloading luma_core-2.5.3-py3-none-any.whl (72 kB)
Downloading smbus2-0.6.1-py2.py3-none-any.whl (11 kB)
Building wheels for collected packages: timeloop, RPi.GPIO, spidev, cbor2, pillow
Building wheel for timeloop (pyproject.toml): started
Building wheel for timeloop (pyproject.toml): finished with status 'done'
Created wheel for timeloop: filename=timeloop-1.0.2-py3-none-any.whl size=3750 sha256=3f2b40fd690e67ad0013c242bc498b3a0a878feb46dc7c3596738f7ee2517ded
Stored in directory: /tmp/pip-ephem-wheel-cache-_woxr1i0/wheels/8c/08/2e/3ce3e345dcf4ba834f60d1e040ab77ac7fd42f0bd06cde4e37
Building wheel for RPi.GPIO (pyproject.toml): started
Building wheel for RPi.GPIO (pyproject.toml): finished with status 'done'
Created wheel for RPi.GPIO: filename=rpi_gpio-0.7.1-cp312-cp312-linux_armv6l.whl size=68795 sha256=0657bbe5855a7747056c4dff4277069ab7d25faab269d47239cc322a7905714a
Stored in directory: /tmp/pip-ephem-wheel-cache-_woxr1i0/wheels/63/75/4e/19132ca8a2e813e52c9e07f84ff41792d7a8ca70138e53c671
Building wheel for spidev (pyproject.toml): started
Building wheel for spidev (pyproject.toml): finished with status 'done'
Created wheel for spidev: filename=spidev-3.8-cp312-cp312-linux_armv6l.whl size=44552 sha256=b943277ea5f7c9bca371318b41f9464d24a73b9b42c66c7b1e38c0d1d8a6f777
Stored in directory: /tmp/pip-ephem-wheel-cache-_woxr1i0/wheels/52/52/d0/de1ca6c54f08a7ec8c99844a6adff825366800f3e06d78ee05
Building wheel for cbor2 (pyproject.toml): started
Building wheel for cbor2 (pyproject.toml): finished with status 'error'
error: subprocess-exited-with-error
× Building wheel for cbor2 (pyproject.toml) did not run successfully.
│ exit code: 1
╰─> [31 lines of output]
running bdist_wheel
running build
running build_py
creating build/lib.linux-armv6l-cpython-312/cbor2
copying python/cbor2/tool.py -> build/lib.linux-armv6l-cpython-312/cbor2
copying python/cbor2/init.py -> build/lib.linux-armv6l-cpython-312/cbor2
running egg_info
writing python/cbor2.egg-info/PKG-INFO
writing dependency_links to python/cbor2.egg-info/dependency_links.txt
writing entry points to python/cbor2.egg-info/entry_points.txt
writing top-level names to python/cbor2.egg-info/top_level.txt
/tmp/pip-build-env-lqncfval/overlay/lib/python3.12/site-packages/vcs_versioning/overrides.py:609: UserWarning: No GlobalOverrides context is active. Auto-creating one with SETUPTOOLS_SCM prefix for backwards compatibility. Consider using 'with GlobalOverrides.from_env("YOUR_TOOL"):' explicitly.
return get_active_overrides().subprocess_timeout
reading manifest file 'python/cbor2.egg-info/SOURCES.txt'
adding license file 'LICENSE.txt'
writing manifest file 'python/cbor2.egg-info/SOURCES.txt'
copying python/cbor2/init.pyi -> build/lib.linux-armv6l-cpython-312/cbor2
copying python/cbor2/py.typed -> build/lib.linux-armv6l-cpython-312/cbor2
running build_ext
running build_rust
error: can't find Rust compiler
If you are using an outdated pip version, it is possible a prebuilt wheel is available for this package but pip is not able to install from it. Installing from the wheel would avoid the need for a Rust compiler.
To update pip, run:
pip install --upgrade pip
and then retry package installation.
If you did intend to build this package from source, try installing a Rust compiler from your system package manager and ensure it is on the PATH during installation. Alternatively, rustup (available at https://rustup.rs) is the recommended way to download and update the Rust compiler toolchain.
[end of output]
note: This error originates from a subprocess, and is likely not a problem with pip.

ERROR: Failed building wheel for cbor2

Building wheel for pillow (pyproject.toml): started
Building wheel for pillow (pyproject.toml): finished with status 'done'
Created wheel for pillow: filename=pillow-12.2.0-cp312-cp312-linux_armv6l.whl size=1251987 sha256=bb447fa81e7fafcdef40ecdee3c05a84b23e6ba3a6871db889842981c4529cca
Stored in directory: /tmp/pip-ephem-wheel-cache-_woxr1i0/wheels/60/ed/42/3288b3b0bb6129b8d20f254a8bde1fa05c637151e908129619
Successfully built timeloop RPi.GPIO spidev pillow
Failed to build cbor2

[notice] A new release of pip is available: 25.0.1 -> 26.1.1
[notice] To update, run: pip install --upgrade pip

ERROR: Failed to build installable wheels for some pyproject.toml based projects (cbor2)

Removing intermediate container 17baf3ed26eb
The command '/bin/sh -c pip install --no-cache-dir -r requirements.txt' returned a non-zero code: 1

Any help appreciated.
Thanks

[steco]

Hi @mbh-dev , it looks like this is because you are running on a Pi Zero, and the build is picking cbor2 version 6.0.1 which doesn't have a pre-build "wheel" for armv6l after version 5.9.0. cbor2 is pulled in by the luma.core library.

I've created a PR here which pins the version of cbor2 to 5.9.0. I've tested runnlng in local mode but haven't yet tested its deployment via the Balena builders.

Confirmed it works on the Balena build infrastructure for both Raspberry Pi V1 / Zero and Raspberry Pi Zero 2.

From Claude Sonnet 4.6:

The issue is a architecture/platform mismatch with cbor2.

Here's what's happening:
Balena Cloud builds for the target device's architecture, which in their case is armv6l (e.g. a Pi Zero). cbor2 6.0.1 (the 
version pip resolved for them) has a Rust extension that must be compiled from source on armv6l because there's no 
\pre-built wheel for that platform. Their build environment doesn't have a Rust compiler, so it fails.

Your local balena push succeeds because you're building directly on the device (or a close enough environment) where pip 
resolves cbor2 6.1.1, which does have a pre-built musllinux aarch64 wheel — so no Rust compilation is needed. You can see 
this in your build log: it downloads cbor2-6.1.1-cp312-cp312-musllinux_1_2_aarch64.whl directly.

The fix is to pin cbor2 to a version that has a pre-built wheel for their target architecture, or better, to pin it to >=6.1.1 which 
resolved the issue for you. The reporter is likely on a Pi Zero (armv6l) rather than a Pi 3/4/Zero 2 (aarch64), which means 
they may be out of luck with a binary wheel regardless — but the more actionable fix for the repo is to pin cbor2>=6.1.1 in 
requirements.txt, since 6.1.1 introduced the pre-built musllinux wheels that avoid the Rust build step.


You could also suggest that if they're on a Pi Zero (true armv6l), they may need to either add Rust to their Dockerfile build 
stage, or switch to a Pi Zero 2 W (which is aarch64 and would get the binary wheel).