Reproduce a production-only bug locally with Docker Compose and debugpy

# ======================================================================
# Q: How do you reproduce locally a bug that appears only in production?
#
# Many bugs are about data or concurrency: legacy records from ASP with NULLs or
# odd encodings, two workers running at the same time. So: the same PostgreSQL
# version, an anonymized dump, a real Celery worker (not eager mode, which hides
# race conditions and on_commit). For step-by-step debugging I put in
# breakpoint() or attach the IDE through debugpy.
# ======================================================================

# docker-compose.debug.yml
services:
  db:
    image: postgres:16                 # same major version as production
    environment: { POSTGRES_PASSWORD: dev }
    volumes: ["./dumps:/dumps"]
  redis:
    image: redis:7
  web:
    build: .
    environment:
      DATABASE_URL: postgres://postgres:dev@db/app
      CELERY_TASK_ALWAYS_EAGER: "false"
    ports: ["8000:8000", "5678:5678"]  # 5678 for debugpy
    command: python -m debugpy --listen 0.0.0.0:5678 manage.py runserver 0.0.0.0:8000
  worker:
    build: .
    command: celery -A app worker -l info --concurrency 4

# anonymized dump from staging
# pg_restore -d app --no-owner /dumps/staging_anon.dump