Setup replication slot for postgres

docker-compose.yml

version: '3.1'

services:
  db:
    image: postgres:13-alpine
    restart: always
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=test
    command:
      - postgres
      - -c
      - max_wal_senders=20
      - -c
      - wal_sender_timeout=0
      - -c
      - max_replication_slots=10
      - -c
      - wal_level=logical
    ports:
      - "5432:5432"
    volumes:
      - ./postgres_init.sql:/docker-entrypoint-initdb.d/postgres_init.sql

postgres_init.sql

CREATE TABLE logs
(
    id         bigserial primary key,
    log        text,
    created_at timestamp default now() not null
);

CREATE USER replication_user  PASSWORD 'pass123';

GRANT USAGE ON SCHEMA "public" TO replication_user;
GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO replication_user;
ALTER DEFAULT PRIVILEGES IN SCHEMA "public" GRANT SELECT ON TABLES TO replication_user;

ALTER USER replication_user WITH replication;

CREATE PUBLICATION logs_pub FOR TABLE logs;
SELECT pg_create_logical_replication_slot('pgoutput_slot', 'pgoutput');

-- tests
SELECT * FROM pg_publication_tables;
SELECT count(*) FROM pg_logical_slot_peek_binary_changes('pgoutput_slot', null, null, 'proto_version', '1', 'publication_names', 'logs_pub');
SELECT * FROM pg_logical_slot_get_binary_changes('pgoutput_slot', null, null, 'proto_version', '1', 'publication_names', 'logs_pub');


-- insert into logs(log) values ('test');