Docker无法在Travis CI中与Postgresql建立连接

Question

我正在尝试将Travis CI集成到我的Rails应用程序中。 在我的本地计算机（ubuntu，Windows）上一切正常，但是在travis主机上存在连接错误。 所以，这是我的配置。

.travis.yml ：

sudo: required

language: ruby

services:
  - docker

env:
  DOCKER_COMPOSE_VERSION: 1.13.0

before_install:
  - sudo rm /usr/local/bin/docker-compose
  - curl -L https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-`uname -s`-`uname -m` > docker-compose
  - chmod +x docker-compose
  - sudo mv docker-compose /usr/local/bin
  - sudo apt-get update
  - sudo apt-get -y -o Dpkg::Options::="--force-confnew" install docker-engine
  - docker-compose build
  - docker-compose -f docker-compose.commands.yml run --rm website rails db:create db:migrate db:test:prepare

script:
 - docker-compose -f docker-compose.commands.yml run --rm -e RAILS_ENV=test website rspec

database.yml ：

development: &default
adapter: postgresql
database: my_app_development
username: postgres
host: postgres
port: 5432

docker-compose.commands.yml ：

version: '3'

services:
  postgres:
    image: 'postgres:9.6.2'
    ports:
      - "5432"

  website:
    depends_on:
      - 'postgres'
    build: .
    ports:
      - '3000'
  volumes:
    - '.:/my_app'
    - 'bundle_data:/bundle'

 volumes:
  bundle_data:

但是travis日志在运行迁移时会输出此信息

状态：为Postgres下载的较新图像：9.6.2

创建myapp_postgres_1 ...

创建myapp_postgres_1

无法连接到服务器：连接被拒绝服务器是否在主机“ postgres”（172.18.0.2）上运行并接受端口5432上的TCP / IP连接？ 无法为{“ adapter” =>“ postgresql”，“ encoding” =>“ unicode”，“ database” =>“ my_app_development”，“ pool” => 5，“ username” =>“ postgres”创建数据库， “ host” =>“ postgres”，“ port” => 5432}导轨中断！ PG :: ConnectionBad：无法连接到服务器：连接被拒绝服务器是否在主机“ postgres”（172.18.0.2）上运行并接受端口5432上的TCP / IP连接？

Answer 1

感谢@ johnharris85和@jbielick，我找到了这个解决方案：

website:
    depends_on:
      - 'postgres'
    build: .
    ports:
      - '3000'
    volumes:
      - '.:/my_app'
      - 'bundle_data:/bundle'
    entrypoint: ./wait-for-postgres.sh postgres 5432

  postgres:
    image: 'postgres:9.6.2'
    ports:
      - '5432'

wait-for-postgres.sh ：

#!/bin/sh

postgres_host=$1
postgres_port=$2
shift 2
cmd="$@"

# wait for the postgres docker to be running
while ! pg_isready -h $postgres_host -p $postgres_port -q -U postgres; do
  >&2 echo "Postgres is unavailable - sleeping"
  sleep 1
done

>&2 echo "Postgres is up - executing command"

# run the command
exec $cmd