docker-compose: How to check postgresql is up

Question

I have a docker compose file as below. One of the service starts a postgresql server.

version: "3.7"
services:
  postgresql:
    image: "postgres:13-alpine"
    restart: always
    volumes:
      - type: bind
        source: ./DO_NOT_DELETE_postgres_data
        target: /var/lib/postgresql/data
    environment:
      POSTGRES_DB: test
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: abc123
      PGDATA: "/var/lib/postgresql/data/pgdata"
    networks:
      - postgresql_network

   otherservice:
      .... (there are few other services also here)

networks:
  postgresql_network:
    driver: bridge

Now I try to start the docker compose

docker-compose up -d

Now after this I have do some things with the postgresql database from another service otherservice

eg:

docker-compose exec otherservice psql -h postgresql -U postgres -p abc123

How to check the postgresql service is up

Answer 1

How to check the postgresql service is up

just to check the status you can just simply do docker-compose ps and look at the status.

To see if the service is just just up but is also ready (aka healthy), you can utilize health checks. Use pg_isready for that.

If you want to start that other service only after the postgres service is up, go with depends_on directive.