x-pg-common:
  &pg-common
  image: postgres-tc:17
  user: postgres
  restart: always
  healthcheck:
    test: 'pg_isready -U postgres --dbname=postgres'
    interval: 10s
    timeout: 5s
    retries: 5

services:
  pg_primary:
    <<: *pg-common
    ports:
      - 15432:5432
    environment:
      POSTGRES_USER: postgres
      POSTGRES_DB: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_HOST_AUTH_METHOD: "scram-sha-256\nhost replication all 0.0.0.0/0 md5"
      POSTGRES_INITDB_ARGS: "--auth-host=scram-sha-256"
    networks:
      default: {}
      pg_backend:
        aliases:
          - pg_primary_int
    cap_add:
      - NET_ADMIN
    command: |
      postgres
        -c wal_level=replica
        -c hot_standby=on
        -c max_wal_senders=10
        -c max_connections=500
        -c max_replication_slots=10
        -c hot_standby_feedback=on
    volumes:
      - ./conf/postgres/00_init.sql:/docker-entrypoint-initdb.d/00_init.sql

  pg_replica:
    <<: *pg-common
    ports:
      - 15433:5432
    environment:
      PGUSER: repluser
      PGPASSWORD: replpass
    networks:
      - default
      - pg_backend
    cap_add:
      - NET_ADMIN
    command: |
      bash -c "
      until pg_basebackup --pgdata=/var/lib/postgresql/data -R --slot=replication_slot --host=pg_primary_int --port=5432
      do
      echo 'Waiting for primary to connect...'
      sleep 1s
      done
      echo 'Backup done, starting replica...'
      chmod 0700 /var/lib/postgresql/data
      postgres -c max_connections=500
      "
    depends_on:
      - pg_primary

networks:
  pg_backend:
    driver: bridge
    internal: true