Cannot create database when running docker-compose.yml - docker

Question

When running docker-compose up -d, I expect 2 databases to be created.
docker-compose.yml:
version: '3.4'
volumes:
db_data:
services:
postgres:
image: postgres:alpine
environment:
- POSTGRES_PASSWORD=Password123
- POSTGRES_DB=database1
ports:
- "5432:5432"
platform:
image: image1/platform:${TAG:-latest}
build:
context: .
dockerfile: PlatformApi/Dockerfile
restart: on-failure
environment:
- ASPNETCORE_ENVIRONMENT=Local
- ConnectionStrings__DefaultConnection=Server=postgres;Port=5432;Uid=postgres;Pwd=Password123;Database=database1
ports:
- "5001:80"
depends_on:
- postgres
volumes:
- .docker/setup.sql:/docker-entrypoint-initdb.d/setup.sql
- db_data:/var/lib/mysql
identity:
image: image2/identity:${TAG:-latest}
build:
context: .
dockerfile: Identity/Dockerfile
restart: on-failure
environment:
- ASPNETCORE_ENVIRONMENT=Local
- ConnectionStrings__DefaultConnection=Server=postgres;Port=5432;Uid=postgres;Pwd=Password123;Database=database2
ports:
- "5002:80"
depends_on:
- postgres
volumes:
- .docker/setup.sql:/docker-entrypoint-initdb.d/setup.sql
- db_data:/var/lib/mysql
This is my setup.sql file which is located inside a .docker folder
CREATE DATABASE IF NOT EXISTS database1;
CREATE USER postgres IDENTIFIED BY Password123;
GRANT CREATE, ALTER, INDEX, LOCK TABLES, REFERENCES, UPDATE, DELETE, DROP, SELECT, INSERT ON database1.* TO postgres;
CREATE DATABASE IF NOT EXISTS database2;
CREATE USER postgres IDENTIFIED BY Password123;
GRANT CREATE, ALTER, INDEX, LOCK TABLES, REFERENCES, UPDATE, DELETE, DROP, SELECT, INSERT ON database2.* TO postgres;
FLUSH PRIVILEGES;
When I run docker-compose up -d, 3 containers are created but 1 of them is exited with an error database "database2" does not exist.
What did I do wrong? Did the setup.sql file not execute or is the content incorrect?

Answer 1

In the postgres service you initiate the Database with the following config
postgres:
image: postgres:alpine
environment:
- POSTGRES_PASSWORD=Password123
- POSTGRES_DB=database1
ports:
- "5432:5432"
As a result a database with name database1 is created
In the following services you try to firstly connect to the database
In platform service:
- ConnectionStrings__DefaultConnection=...;Database=database1
Here there is no issue since database1 exists
But in identity service:
- ConnectionStrings__DefaultConnection=...;Database=database2
You try to connect to database2 which does not exist
The reason it does not exist is that there are race conditions in your setup.sql. You can not guarantee that when the identity service initiates, that the database2 would be already created by platform service.
To tackle this, you could add postgres2 service which creates the database2
postgres2:
image: postgres:alpine
environment:
- POSTGRES_PASSWORD=Password123
- POSTGRES_DB=database2
ports:
- "5433:5432"
identity:
image: image2/identity:${TAG:-latest}
build:
context: .
dockerfile: Identity/Dockerfile
restart: on-failure
environment:
- ASPNETCORE_ENVIRONMENT=Local
- ConnectionStrings__DefaultConnection=Server=postgres2;Port=5432;Uid=postgres;Pwd=Password123;Database=database2
ports:
- "5002:80"
depends_on:
- postgres2
volumes:
- .docker/setup.sql:/docker-entrypoint-initdb.d/setup.sql
- db_data:/var/lib/mysql