How to connect to PostgreSQL using docker-compose? - postgresql

Question

Want to use docker-compose to run api application and postgresql database together.
docker-compose file:
version: '3'
volumes:
database_data:
driver: local
services:
db:
image: postgres:latest
volumes:
- database_data:/var/lib/postgresql/data
api:
build: ./api
expose:
- 8080
ports:
- 8080:8080
volumes:
- ./api:/usr/src/app/
links:
- db
environment:
- PGHOST=db
- PGDATABASE=postgres
- PGUSER=postgres
Api main.go file:
func main() {
db, err = gorm.Open("postgres", "host=db port=5432 user=postgres dbname=postgres")
// ...
}
When run the services, got message from log:
api_1 | [GIN] 2018/06/22 - 07:31:10 | 404 | 1.4404ms | 172.20.0.1 | GET /posts
api_1 |
api_1 | (sql: database is closed)
api_1 | [2018-06-22 07:31:10]
api_1 |
api_1 | (sql: database is closed)
api_1 | [2018-06-22 07:31:10]
api_1 | [GIN] 2018/06/22 - 07:32:14 | 403 | 15.6µs | 172.20.0.1 | GET /posts
db_1 | 2018-06-22 07:34:27.296 UTC [81] FATAL: role "root" does not exist
db_1 | 2018-06-22 07:34:36.897 UTC [90] FATAL: role "root" does not exist
Does this way not good? host=db in the connection string? Since db is the docker compose service name.
Add
It can work:
https://docs.docker.com/samples/library/postgres/#-or-via-psql

Answer 1

In the link you provided there are configuration settings that you did not added
restart: always
environment:
POSTGRES_PASSWORD: example
You should try this
version: '3'
services:
db:
image: postgres:latest
restart: always
ports:
- 5432:5432
environment:
POSTGRES_PASSWORD: 'postgres'
volumes:
- database_data:/var/lib/postgresql/data
api:
build: ./api
expose:
- 8080
ports:
- 8080:8080
volumes:
- ./api:/usr/src/app/
links:
- db
environment:
- PGHOST: 'db'
- PGDATABASE: 'postgres'
- PGUSER: 'postgres'
- PGPASSWORD: 'postgres'
volumes:
database_data:
driver: local
and
db, err := gorm.Open("postgres", "host=db port=5432 user=postgres dbname=postgres password=postgres")