Using docker-compose to create tables in postgresql database

Question

I am using docker-compose to deploy a multicontainer python Flask web application. I'm having difficulty understanding how to create tables in the postgresql database during the build so I don't have to add them manually with psql.

My docker-compose.yml file is:

web:   restart: always   build: ./web   expose:     - "8000"   links:     - postgres:postgres   volumes:     - /usr/src/flask-app/static   env_file: .env   command: /usr/local/bin/gunicorn -w 2 -b :8000 app:app  nginx:   restart: always   build: ./nginx/   ports:     - "80:80"   volumes:     - /www/static   volumes_from:     - web   links:     - web:web  data:   restart: always   image: postgres:latest   volumes:     - /var/lib/postgresql   command: "true"  postgres:   restart: always   image: postgres:latest   volumes_from:     - data   ports:     - "5432:5432" 

I dont want to have to enter psql in order to type in:

CREATE DATABASE my_database; CREATE USER this_user WITH PASSWORD 'password'; GRANT ALL PRIVILEGES ON DATABASE "my_database" to this_user; \i create_tables.sql 

I would appreciate guidance on how to create the tables.

Answer 1

It didn't work for me with the COPY approach in Dockerfile. But I managed to run my init.sql file by adding the following to docker-compose.yml:

    volumes:         - ./init.sql:/docker-entrypoint-initdb.d/init.sql 

init.sql was in the same directory as my docker-compose.yml. I picked the solution from this gist. Check this article for more information.

Answer 2

I dont want to have to enter psql in order to type in

You can simply use container's built-in init mechanism:

COPY init.sql /docker-entrypoint-initdb.d/10-init.sql

This makes sure that your sql is executed after DB server is properly booted up.

Take a look at their entrypoint script. It does some preparations to start psql correctly and looks into /docker-entrypoint-initdb.d/ directory for files ending in .sh, .sql and .sql.gz.

10- in filename is because files are processed in ASCII order. You can name your other init files like 20-create-tables.sql and 30-seed-tables.sql.gz for example and be sure that they are processed in order you need.

Also note that invoking command does not specify the database. Keep that in mind if you are, say, migrating to docker-compose and your existing .sql files don't specify DB either.

Your files will be processed at container's first start instead of build stage though. Since Docker Compose stops images and then resumes them, there's almost no difference, but if it's crucial for you to init the DB at build stage I suggest still using built-in init method by calling /docker-entrypoint.sh from your dockerfile and then cleaning up at /docker-entrypoint-initdb.d/ directory.