docker-compose.yml

# Production-like local stack: PostgreSQL behind a PgBouncer connection pooler.
#
# The Rails app (run on the host via JRuby) connects to PgBouncer on localhost:6432,
# which pools transactions against the internal `postgres` service. This mirrors a
# typical production topology where the app never talks to Postgres directly.
#
# Bring it up with:   docker-compose up -d
# Drive the resilience simulation with:   bin/pgbouncer_resilience
name: myapp-pgbouncer

services:
  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_USER: myapp
      POSTGRES_PASSWORD: myapp
      POSTGRES_DB: myapp_development
    # Not published on the host: only PgBouncer (and `docker-compose exec`) reach it,
    # which also avoids clashing with any local Postgres already on 5432.
    expose:
      - "5432"
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U myapp -d myapp_development"]
      interval: 2s
      timeout: 3s
      retries: 30

  pgbouncer:
    image: edoburu/pgbouncer:latest
    depends_on:
      postgres:
        condition: service_healthy
    # Run PgBouncer directly against our mounted config instead of the image's
    # env-driven template, so we control pool_mode, lifetimes, and admin access.
    entrypoint: ["pgbouncer", "/etc/pgbouncer/pgbouncer.ini"]
    volumes:
      - ./docker/pgbouncer/pgbouncer.ini:/etc/pgbouncer/pgbouncer.ini:ro
      - ./docker/pgbouncer/userlist.txt:/etc/pgbouncer/userlist.txt:ro
    ports:
      - "6432:6432"