Debug: Python script works locally but fails in CI/CD

Python code works on local machine but fails in CI/CD pipeline with import errors, path issues, or missing dependencies.

Common causes of local vs CI differences:

1. Python version mismatch:

# Check CI Python version:
python3 --version
# Match locally: pyenv install 3.11.7 && pyenv local 3.11.7
# In CI config: specify exact version

1. Missing system dependencies:

# Packages with C extensions need system libs
# Add to CI: apt-get install libpq-dev (for psycopg2)
# Or use: pip install psycopg2-binary

1. Different OS (macOS local, Linux CI):

# Path separators: os.path vs pathlib
# Case sensitivity: macOS is case-insensitive!
# from utils import MyClass # Works on macOS even if file is Utils.py

1. Working directory differs:

# Don't use relative paths from script location
# Use: Path(__file__).parent / 'data' / 'config.json'

1. Environment variables missing:

# List what CI provides: env | sort
# Set in CI config or .env file

1. Timezone differences:

# CI might be UTC, local might be different
# Always use UTC internally: datetime.now(timezone.utc)

1. Dependencies not pinned:

# pip install -r requirements.txt
# Use pip freeze locally, commit exact versions

1. File permissions:

# Scripts need execute permission: chmod +x script.py
# Git: git update-index --chmod=+x script.py