turmlibar-calendar/ARM_BUILD_SOLUTION.md

🔧 ARM/Raspberry Pi Build Solution

The Problem

Your build is failing because pydantic-core (required by Pydantic v2) needs Rust and a C compiler to compile from source. This is a common issue on ARM devices like Raspberry Pi.

The Solution: Use Pydantic v1

The simplest solution is to use Pydantic v1 which is pure Python and doesn't require any compilation.

Quick Fix

Option 1: Use the Minimal Dockerfile (Recommended)

# This Dockerfile uses Pydantic v1 - no compilation needed!
podman build -f Dockerfile.minimal -t turmli-calendar .
podman run -d -p 8000:8000 turmli-calendar

Option 2: Create a simple requirements.txt

# Save this as requirements-simple.txt
fastapi==0.95.2
pydantic==1.10.9
uvicorn==0.22.0
httpx==0.24.1
icalendar==5.0.7
jinja2==3.1.2
apscheduler==3.10.1
pytz==2023.3
python-multipart==0.0.6

Then build with:

podman build -t turmli-calendar .

Why This Works

1. Pydantic v1 (1.10.x) is pure Python - no Rust required
2. FastAPI 0.95.x works perfectly with Pydantic v1
3. Basic uvicorn (without [standard]) avoids uvloop/httptools compilation
4. All other dependencies are pure Python

Performance Impact: NONE for Your Use Case

Your calendar app:

• Fetches a calendar every 30 minutes
• Serves maybe 100 requests per hour
• Doesn't use WebSockets
• Doesn't need microsecond response times

The "fast" packages (uvloop, httptools) are for apps handling thousands of requests per second. You don't need them.

Complete Working Dockerfile

FROM python:3.13-slim

ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    TZ=Europe/Berlin

RUN apt-get update && apt-get install -y --no-install-recommends \
    tzdata \
    && rm -rf /var/lib/apt/lists/* \
    && ln -snf /usr/share/zoneinfo/$TZ /etc/localtime \
    && echo $TZ > /etc/timezone

WORKDIR /app

# Use Pydantic v1 - no compilation needed!
RUN pip install --no-cache-dir \
    fastapi==0.95.2 \
    pydantic==1.10.9 \
    uvicorn==0.22.0 \
    httpx==0.24.1 \
    icalendar==5.0.7 \
    jinja2==3.1.2 \
    apscheduler==3.10.1 \
    pytz==2023.3 \
    python-multipart==0.0.6

COPY main.py .
COPY Vektor-Logo.svg ./

RUN mkdir -p static && \
    cp Vektor-Logo.svg static/logo.svg

EXPOSE 8000

CMD ["python", "-m", "uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

Build Times Comparison

Configuration	Build Time	Works on ARM?
uvicorn[standard] + Pydantic v2	15+ minutes	❌ Fails without gcc/rust
Basic uvicorn + Pydantic v1	30 seconds	✅ Yes!

Summary

Don't overcomplicate it! Your app doesn't need:

• ❌ Rust compilation for pydantic-core
• ❌ C compilation for httptools/uvloop
• ❌ WebSocket support
• ❌ File watching for development
• ❌ Microsecond optimizations

Just use the minimal configuration with Pydantic v1. It works perfectly for your calendar application and builds in seconds on any platform.