将 docker 服务连接到 docker 数据库容器时出现 Postgres ENOTFOUND 错误

Question

I can't get one of my containers (service) to connect to the postgres database container through docker. It seems to be complaining about using the wrong database...(I'm using node.js with the 'pg' and 'pg-promise' libraries.).

My postgres connection info

const pg = require('pg');
const pgp = require('pg-promise')();

var config = {
  user: 'root',
  password: 'myPassword',
  database: 'myDb',
  host: 'database',
  port: 5432
};
const db = pgp(config);

Error when docker attempts to connect to the database

{ Error: getaddrinfo ENOTFOUND database database:5432
    at errnoException (dns.js:28:10)
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:76:26)
  code: 'ENOTFOUND',
  errno: 'ENOTFOUND',
  syscall: 'getaddrinfo',
  hostname: 'database',
  host: 'database',
  port: 5432 }

I know that by default the container has the same hostname as the service name, but that didn't work (my service name is "database"). Anything I'm missing?

docker-compose.yml

version: '3'

services:
  myapp:
    build: My-App/
    depends_on:
      - 'database'
    ports:
      - '5000:5000'

  database:
    image: postgres:11.5

Answer 1

So I eventually found the answer, so I thought I'd share:

The reason Docker couldn't automatically connect to Postgres was because Postgres was still initializing (and not receiving connection requests while it booted up).

One solution I found was to artificially delay Docker's connection attempt (basically wait until Postgres is ready before attempting to connect).

EDIT: Docker-compose version 3 now has docs on how to control which containers start first: https://docs.docker.com/compose/startup-order/