用于 postgres 数据的 docker 中的卷挂载

Question

I am trying to insert data into postgres using docker.

I have a folder in my code named data which has insert commands and has one file named init.sql .
I want to insert the data from init.sql present in folder data to tables present in docker.

version: '3.1'

services:
  postgres:  
    image: postgres:11.6-alpine 
    restart: always
    ports:
      - "5432:5432"
    environment:
      POSTGRES_PORT: 5432
    volumes:
      - ./tables:/docker-entrypoint-initdb.d/
      - ./data:/var/lib/postgresql/data
volumes:
  data: {}

I am trying this but I get the error:

initdb: directory "/var/lib/postgresql/data" exists but is not empty

I think I am not using the correct use case, I am new to docker compose.
But is there any way, my use case can get satisfied?

Answer 1

This is caused by an improper usage of the volumes syntax for your named volume .
In order to mount a named volume you have to just use its name like this:

    volumes:
      - data:/var/lib/postgresql/data

If your syntax begins with a . then it will be a bind mount from your host.

    volumes:
      - ./data:/var/lib/postgresql/data

The above code is mounting the host folder data relative to where you your docker-compose.yml is located.

This docker-compose.yml should do what you expect.

version: '3.1'

services:
  postgres:  
    image: postgres:11.6-alpine 
    restart: always
    ports:
      - "5432:5432"
    environment:
      POSTGRES_PORT: 5432
    volumes:
      - ./tables:/docker-entrypoint-initdb.d/
      - data:/var/lib/postgresql/data
volumes:
  data:

---

If for some reason your volume has been created already, with an empty or no database, your first step should be running:

docker-compose down --volumes

From the documentation:

-v, --volumes           Remove named volumes declared in the `volumes`
                        section of the Compose file and anonymous volumes
                        attached to containers.

^{From: https://docs.docker.com/compose/reference/down/}