Postgres Initialize script not working Docker version 3.4 - postgresql

Question

Trying to dockerize an application and in my application, i have the following
docker-compose.yml
version: '3.4'
services:
app:
build:
context: .
dockerfile: Dockerfile
depends_on:
- database
ports:
- "3000:3000"
volumes:
- .:/app
- gem_cache:/usr/local/bundle/gems
env_file: .env
environment:
RAILS_ENV: development
database:
image: postgres:10.12
volumes:
- ./init.sql/:/docker-entrypoint-initdb.d/init.sql
- db_data:/var/lib/postgresql/data
volumes:
gem_cache:
db_data:
In my init.sql file
CREATE USER user1 WITH PASSWORD 'password';
ALTER USER user1 WITH SUPERUSER;
i have already run chmod +x init.sql
In my .env file i have the following
DATABASE_NAME=tools_development
DATABASE_USER=user1
DATABASE_PASSWORD=password
DATABASE_HOST=database
And this is my Dockerfile
FROM ruby:2.7.0
ENV BUNDLER_VERSION=2.1.4
RUN apt-get -y update --fix-missing
RUN apt-get install -y bash git build-essential nodejs libxml2-dev openssh-server libssl-dev libreadline-dev zlib1g-dev postgresql-client libcurl4-openssl-dev libxml2-dev libpq-dev tzdata
RUN gem install bundler -v 2.1.4
WORKDIR /app
COPY Gemfile Gemfile.lock ./
RUN bundle check || bundle install
COPY . ./
ENTRYPOINT ["./entrypoint.sh"]
But each time I run docker-compose run --build and try to run my application. I get error:
could not translate host name "database" to address: Name or service not known
I have tried everything possible but still the same error.
Does anyone have any idea on how to fix this issue?
I know the issue is happening because the postgres initialize scripts are not running. I have seen a lot of options online and i have tried everything but I am still facing the same error.
Any help is appreciated
Thanks

Answer 1

From the postgres docker image documentation you can see that the POSTGRES_USER and POSTGRES_PASSWORD are the necessary environment variables to setup the postgres container
You could add these environment variables to your .env file. So the file will be as follow:
.env
DATABASE_NAME=tools_development
DATABASE_USER=user1
DATABASE_PASSWORD=password
DATABASE_HOST=database
POSTGRES_USER=user1
POSTGRES_PASSWORD=password
POSTGRES_DB=tools_development
These environment variables will be used from the postgres container to init the DB and assign the user, so you can get rid of the init.sql file
After that you need to add the reference of the .env file in the database(postgres:10.12) service.
So your docker compose file should be as follow:
docker-compose.yml
...
database:
image: postgres:10.12
volumes:
- db_data:/var/lib/postgresql/data
env_file: .env
...