Garmin Daily Report: Step 3 – Dockerize for Raspberry Pi

Overview

Containerize the Garmin report scripts so they run cleanly on a Raspberry Pi 2 without installing Python, pip, or any dependencies on the host. The container spins up, runs the script, and exits — no resources wasted.

Prerequisites

Raspberry Pi with Docker and Docker Compose installed
The garminconnector repository cloned on the Pi
config.py with Garmin credentials on the Pi

Step 1: Dockerfile

The Dockerfile uses python:3.11-slim as the base image with only the garth dependency:

FROM python:3.11-slim

WORKDIR /app

# Install dependencies
RUN pip install --no-cache-dir "garth>=0.5.17,<0.6.0"

# Copy project files
COPY garminconnect/ ./garminconnect/
COPY custom_scripts/ ./custom_scripts/

# Default script (override with any script at runtime)
CMD ["python3", "custom_scripts/daily_report.py"]

Key design decisions:

python:3.11-slim — Small image, has everything needed
Only garth dependency — The garminconnect library is copied directly
CMD sets the default script, but can be overridden at runtime

Step 2: Docker Compose

services:
  garmin-report:
    build: .
    volumes:
      - ./config.py:/app/config.py:ro
      - garth-tokens:/root/.garth
    environment:
      - TZ=Australia/Sydney

volumes:
  garth-tokens:

Key details:

config.py is mounted read-only (:ro) — credentials stay on the host, not baked into the image
garth-tokens is a named volume — OAuth tokens persist between container runs
TZ=Australia/Sydney — Ensures correct timezone for report dates

Step 3: Build & Test on the Pi

SSH into the Pi and run:

cd ~/garminconnector
git pull
docker compose build

Create config.py if it doesn’t exist:

cp config.example.py config.py
nano config.py
# Fill in your Garmin email and password

Test the daily report:

docker compose run --rm garmin-report

Success: You should see the full daily health report output in your terminal.

Running Different Scripts

The Docker image contains all scripts from custom_scripts/. Override the default command to run any of them:

# Daily report (default)
docker compose run --rm garmin-report

# Weekly report
docker compose run --rm garmin-report python3 custom_scripts/weekly_report.py

# Trainer report
docker compose run --rm garmin-report python3 custom_scripts/trainer_report.py

# Heart rate analysis
docker compose run --rm garmin-report python3 custom_scripts/heart_rate_analysis.py

One Docker image, any script.

How It Works

docker compose run --rm garmin-report
         │
         ▼
┌─────────────────────┐
│  Spin up container  │
│  python:3.11-slim   │
├─────────────────────┤
│  Mount config.py    │  ← credentials from host
│  Mount garth-tokens │  ← persisted OAuth tokens
├─────────────────────┤
│  Run daily_report   │  ← fetches Garmin API data
│  Print output       │  ← captured by caller
├─────────────────────┤
│  Container exits    │
│  --rm removes it    │  ← clean, no leftover containers
└─────────────────────┘

Updating

When you update scripts on your Mac and push to git:

# On the Pi
cd ~/garminconnector
git pull
docker compose build

The image rebuilds with the latest scripts.