Extend docker postgres image to create extra database - postgresql

Question

I've already seen this topic : https://stackoverflow.com/a/26599273/2323245
But I have the following problem :
postgres_1 | FATAL: role "docker" does not exist
app_1 | Error: Could not establish a connection with the database
This is my docker-compose.yml file
version: "2"
services:
app:
build:
context: .
dockerfile: Dockerfiles/app.dockerfile
links:
- postgres
depends_on:
- postgres
ports:
- "8080:8080"
environment:
PORT: 8080
networks:
- neo_dev
restart: always
postgres:
build:
context: .
dockerfile: Dockerfiles/postgres.dockerfile
networks:
- neo_dev
volumes:
- postgresql:/var/lib/postgresql
# This needs explicit mapping due to https://github.com/docker-library/postgres/blob/4e48e3228a30763913ece952c611e5e9b95c8759/Dockerfile.template#L52
- postgresql_data:/var/lib/postgresql/data
ports:
- "5430:5432" #in case you already have postgres running in your host machine
networks:
neo_dev:
driver: bridge
volumes:
postgresql:
postgresql_data:
My postgres.dockerfile is
FROM library/postgres
MAINTAINER Samir Bouaked "sbouaked#neocasesoftware.com"
ADD Dockerfiles/init.sql /docker-entrypoint-initdb.d/
And this is my init.sql file
CREATE USER docker with password 'docker';
CREATE DATABASE docker;
GRANT ALL PRIVILEGES ON DATABASE docker TO docker;
In my golang app, i'm trying to reach the database with
router.GET("/db", func(c *gin.Context) {
db, err := sql.Open("postgres", "host=postgres port=5432 user=docker dbname=docker password=docker sslmode=disable")
if err != nil {
log.Fatal("Error: The data source arguments are not valid - " + err.Error())
}
err = db.Ping()
if err != nil {
log.Println("Error: Could not establish a connection with the database")
c.String(http.StatusOK, "hotstName : %s\nDbStatus : %s", os.Getenv("HOSTNAME"), err)
} else {
c.String(http.StatusOK, "\nhotstName : %s\nDbStatus : connection ok !\n", os.Getenv("HOSTNAME"))
}
defer db.Close()
})
I tried different solutions like passing directly in the dockerfile env variables like that
ENV POSTGRES_USER docker
ENV POSTGRES_PASSWORD docker
ENV POSTGRES_DB docker
But have always the same result...
For more information you can check this repo https://github.com/neocase/docker-go-starter-kit
I don't understand the problem

Answer 1

It was a problem of docker volume.
I have to docker volume rm postgresvolume and do again a docker-compose up --build
It wasn't a problem of environment variables, but juste the fact that the init.sql was in cash and not run at the begining. It's due to some test I make a the start of the project

Answer 2

If you want to create the DB by passing ENV variables using docker-compose you can specify something like
postgres:
container_name: postgres
image: library/postgres
ports:
- "5432:5432"
environment:
- POSTGRES_DATABASE=docker
- POSTGRES_USER=docker
- POSTGRES_PASSWORD=docker
- POSTGRES_ADMIN_PASSWORD=docker
in your compose YML file.
This should create you a postgres container with an DB docker with user/pwd docker, no need for your own dockerfile anymore (so you can use any postgres image that supports this behavior)
After running compose (and if it doesn't work as you expect) you should have a look at the logs if your postgres container is working at all, or if there is an issue with your app.