How To Pass Environment variables in Compose ( docker compose ) - docker-compose

Question

There are multiple parts of Compose that deal with environment variables in one sense or another. So how do I pass Environment variables in Compose ( docker-compose )
According to the documentation If you have multiple environment variables, you can substitute them by adding them to a default environment variable file named .env or by providing a path to your environment variables file using the --env-file command line option.
version: '3.9'
services:
nginx:
image: nginx:stable-alpine
container_name: nginx
ports:
- 80:80
- 443:443
restart: always
volumes:
- ./nginx/nginx.conf:/etc/nginx/nginx.conf
postgres:
container_name: postgres
image: postgres:13-alpine
environment:
- POSTGRES_USER=${DB_USER}
- POSTGRES_PASSWORD=${DB_PASSWORD}
- POSTGRES_DB=${DB_DATABASE}
volumes:
- ./pgdata:/var/lib/postgresql/data
- ./database/app.sql:/docker-entrypoint-initdb.d/app.sql
restart: always
ports:
- "35000:5432"
networks:
- app_network
app-api:
container_name: app-api
build:
dockerfile: Dockerfile
context: ./app-api
target: production
environment:
- DB_TYPE=${DATABASE_TYPE}
- POSTGRES_HOST=${DB_HOST}
- POSTGRES_USER=${DB_USER}
- POSTGRES_PASS=${DB_PASSWORD}
- POSTGRES_DB=${DB_DATABASE}
- POSTGRES_PORT=${DB_PORT}
- APP_PORT=${SERVER_PORT}
- NODE_ENV:production
## AWS
- AWS_S3_ACCESS_KEY=${AWS_S3_ACCESS_KEY}
- AWS_S3_SECRET_ACCESS_KEY=${AWS_S3_SECRET_ACCESS_KEY}
- AWS_S3_BUCKET=${AWS_S3_BUCKET}
- AWS_S3_REGION=${AWS_S3_REGION}
ports:
- "5050:80"
volumes:
- ./pgadmin-data:/var/lib/pgadmin
depends_on:
- postgres
links:
- postgres
networks:
- app_network
pgadmin:
container_name: pgadmin
image: dpage/pgadmin4
restart: always
environment:
- PGADMIN_DEFAULT_EMAIL=${PGADMIN_DEFAULT_EMAIL}
- PGADMIN_DEFAULT_PASSWORD=${PGADMIN_DEFAULT_PASSWORD}
- PGADMIN_LISTEN_PORT=${PGADMIN_LISTEN_PORT}
restart: always
ports:
- "5400:5400"
depends_on:
- postgres
links:
- postgres
networks:
- app_network

Answer 1

you can use it like this. you have to pass value in each environment variable.
server:
environment:
- AWS_S3_ACCESS_KEY=ABCJQHWEQJHWQ
- AWS_S3_SECRET_ACCESS_KEY=ASKJHDAKJHNAWKLHEN
- AWS_S3_BUCKET=abc-text
- AWS_S3_REGION=eu-west-1
ports:
- "5050:80"
volumes:
- ./pgadmin-data:/var/lib/pgadmin
depends_on:
- postgres
links:
- postgres
networks:
- app_network

Answer 2

When you run docker-compose up, the web service defined above uses the image from the defined Dockerfile. You can verify this with the convert command, which prints your resolved application config to the terminal:
You can use this command to verify if you are pathing the proper environment variables
$ docker compose convert
https://docs.docker.com/compose/environment-variables/