Question

我正在构建Rails应用，安装docker时遇到问题。

构建工作正常，但是当我尝试使用此命令创建数据库时：

docker-compose run web bundle exec rails db:create

它抛出此错误：

could not connect to server: Connection refused
        Is the server running on host "localhost" (127.0.0.1) and accepting
        TCP/IP connections on port 5432?
could not connect to server: Address not available
        Is the server running on host "localhost" (::1) and accepting
        TCP/IP connections on port 5432?

我尝试将主机从localhost重命名为db，但没有用，我还尝试编辑etc / hosts。

docker-compose.yml

version: '3'
services:
  localhost:
    image: postgres
    volumes:
      - ./tmp/db:/var/lib/postgresql/data
  web:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    depends_on:
      - localhost
    working_dir: /myapp

Dockerfile

FROM ruby:2.6.2-alpine

RUN apk add --no-cache build-base postgresql-dev tzdata libxml2-dev libxslt-dev nodejs yarn

RUN mkdir /myapp
WORKDIR /myapp

COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock
COPY package.json /myapp/package.json

RUN gem install bundler:2.1.2
RUN bundle install

COPY . /myapp

RUN yarn install --check-files

database.yml

default: &default
  adapter: postgresql
  encoding: unicode
  host: localhost
  username: postgres
  password:
  # For details on connection pooling, see Rails configuration guide
  # https://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: myapp_development

/ etc / hosts

# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1       localhost
255.255.255.255 broadcasthost
::1             localhost
# Added by Docker Desktop
# To allow the same kube context to work on the host and the container:
127.0.0.1 kubernetes.docker.internal
# End of section
127.0.0.1 postgres

如何解决此问题？我不确定我缺少什么！

Answer 1

在Docker中，每个“服务”都在其自己的容器中运行。因此，您将把Rails应用程序和数据库放在不同的容器中。从概念上讲，每个服务都是一台不同的服务器。

您的错误（Is the server running on host "localhost" (127.0.0.1)..）表明您的Rails应用程序正在同一台机器上寻找数据库引擎。该数据库正在单独的服务器上运行。

在docker-compose文件中，每个服务均可通过其名称进行寻址。因此，将Rails应用程序中的连接字符串或设置从localhost更改为db。

编辑：我刚才看到您将数据库服务器命名为localhost，这很麻烦。将其更改为db还是其他？：）

Rails服务器是否在主机“ localhost”（127.0.0.1）上运行并在端口5432上接受TCP / IP连接？

1 个答案: