Docker、Rails、Postgres - 找不到數據庫服務錯誤

Question

文件

FROM ruby:2.6.3
RUN apt-get update -qq && apt-get install -y nodejs postgresql-client
RUN mkdir /paper_scammer_docker
WORKDIR /paper_scammer_docker
COPY Gemfile /paper_scammer_docker/Gemfile
COPY Gemfile.lock /paper_scammer_docker/Gemfile.lock
RUN bundle install
COPY . /paper_scammer_docker

# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]
EXPOSE 3000

# Start the main process.
CMD ["rails", "server", "-b", "0.0.0.0"]

docker-compose.yml

version: '3'
services:
  db:
    image: postgres:10
    ports:
      - "5432:5432"
    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:
      - .:/paper_scammer_docker
    ports:
      - "3000:3000"
    links:
      - "db:db"
    depends_on:
      - db

我能夠使用以下命令成功構建圖像

docker-compose build

如果我在項目根目錄中執行docker-compose up我的應用程序運行良好，當我執行docker container ls時，我可以看到兩個容器，一個用於我的 rails 應用程序，另一個用於 postgres。 我觀察到 postgres 圖像是從庫中加載的。

數據庫.yml 文件

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: postgresql
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000
  host: db
  username: postgres
  password:
  # user: gnpsllco_papaer
  # password: sharma@123

development:
  <<: *default
  database: paper_scammer_development
  # user: postgres
  # password: sharma@123

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: paper_scammer_test
  # user: postgres
  # password: sharma@123

production:
  <<: *default
  database: gnpsllco_paper_scammer

問題

我運行以下命令從我的 rails 應用程序的映像啟動 docker 容器。

sudo docker run -p 3000:3000 paperscammer_web

postgres 容器未運行或丟失。

我想了解這個 dockerfile-compose 如何處理這個，當我旋轉 Rails 應用程序的圖像時，它說它依賴於 postgres 服務不應該它也旋轉 postgres 容器並將“db”設置為連接的主機。

或者是否需要為 postgres 手動旋轉。

當我運行http://localhost:3000時出現以下錯誤

could not translate host name "db" to address: Name or service not known

我可以看到 postgres 容器沒有運行。

謝謝

Answer 1

sudo docker run -p 3000:3000 paperscammer_web將僅啟動 Web 服務器，您需要運行docker-compose ：

sudo docker-compose up -d --build

第二種選擇：

 sudo docker run --name db -p 5432:5432 -v ./tmp/db:/var/lib/postgresql/data postgres:10
 sudo docker run -p 3000:3000 --link db:db -v .:/paper_scammer_docker paperscammer_web

Answer 2

解決方案

./ Dockerfile

ROM ruby:2.6.3-alpine

ENV BUNDLER_VERSION=2.0.2

RUN apk add --update --no-cache \
      binutils-gold \
      build-base \
      curl \
      file \
      g++ \
      gcc \
      git \
      less \
      libstdc++ \
      libffi-dev \
      libc-dev \ 
      linux-headers \
      libxml2-dev \
      libxslt-dev \
      libgcrypt-dev \
      make \
      netcat-openbsd \
      nodejs \
      openssl \
      pkgconfig \
      postgresql-dev \
      python \
      tzdata \
      yarn 

RUN mkdir -p /app
WORKDIR /app

COPY Gemfile* ./
RUN gem install bundler
RUN bundle config build.nokogiri --use-system-libraries
RUN bundle check || bundle install 

COPY package.json yarn.lock ./
RUN yarn install --check-files

COPY . ./

COPY ./sh/entrypoints/docker-entrypoint.sh /usr/bin/entrypoint.sh
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]

./ .env

APP_NAME=api
APP_PORT=3100

DATABASE_NAME=rails_db
DATABASE_USER=batman
DATABASE_PASSWORD=super_pass_123
DATABASE_PORT=5342
DATABASE_HOST=api_db # must be equal to the name of the postgres service in docker-compose.yml

./ docker-compose.yml

version: '3.7'
services:
  api: 
    build:
      context: .
      dockerfile: Dockerfile
    container_name: ${APP_NAME}
    depends_on:     
      - api_db
    ports: 
      - "${APP_PORT}:${APP_PORT}"
    volumes:
      - .:/app
      - gem_cache:/usr/local/bundle/gems
      - node_modules:/app/node_modules
    env_file: .env
    environment:
      RAILS_ENV: development

  api_db: # must be equal to `DATABASE_HOST ` in ./.env
    image: postgres
    command: postgres -c logging_collector=on -c log_destination=stderr -c log_directory=/logs -p ${DATABASE_PORT}
    ports:
      - "${DATABASE_PORT}:${DATABASE_PORT}"
    volumes:
      - db_data:/var/lib/postgresql/data
      - ./log/db:/logs
    environment:
      - POSTGRES_USER=${DATABASE_USER}
      - POSTGRES_PASSWORD=${DATABASE_PASSWORD}
      - POSTGRES_DB=${DATABASE_NAME}

volumes:
  gem_cache:
  db_data:
  node_modules:  

./sh/entrypoints/ docker-entrypoint.sh

https://stackoverflow.com/a/59047028/4488252

DB_INITED=0
if db_version=$(bundle exec rake db:version 2>/dev/null)
then
    if [ "$db_version" = "Current version: 0" ]
    then
        echo "DB is empty"
    else
        echo "DB exists"
        DB_INITED=1
    fi
    bundle exec rake db:migrate 
else
    echo "DB does not exist"
    bundle exec rake db:setup
fi

if [ $DB_INITED == 0 ]
then
    echo "Performing initial configuration"
    # init some plugins, updated db if need, add initial data
fi

./config/的database.yml

default: &default
  adapter: postgresql
  encoding: unicode
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  database: <%= ENV['DATABASE_NAME'] %>
  username: <%= ENV['DATABASE_USER'] %>
  password: <%= ENV['DATABASE_PASSWORD'] %>
  port: <%= ENV['DATABASE_PORT'] || '5432' %>
  host: <%= ENV['DATABASE_HOST'] %>

development:
  <<: *default

test:
  <<: *default

production:
  <<: *default

./ .dockerignore

https://gist.github.com/neckhair/ace5d1679dd896b71403fda4bc217b9e

.git
.gitignore
README.md

#
# OS X
#
.DS_Store
.AppleDouble
.LSOverride
# Icon must end with two \r
Icon
# Thumbnails
._*
# Files that might appear on external disk
.Spotlight-V100
.Trashes
# Directories potentially created on remote AFP share
.AppleDB
.AppleDesktop
Network Trash Folder
Temporary Items
.apdisk

#
# Rails
#
.env
.env.sample
*.rbc
capybara-*.html
log
tmp
db/*.sqlite3
db/*.sqlite3-journal
public/system
coverage/
spec/tmp
**.orig

.bundle

.ruby-version
.ruby-gemset

.rvmrc

# if using bower-rails ignore default bower_components path bower.json files
vendor/assets/bower_components
*.bowerrc
bower.json

用法

https://docs.docker.com/compose/reference/down/

構建並運行： docker-compose up --build -d

https://docs.docker.com/compose/reference/down/

停止： docker-compose down

停止 + 刪除圖像和卷： docker-compose down --rmi all --volumes

Answer 3

docker-compose up和docker run是不同的命令。 使用后者不會使用撰寫文件，只會使用傳遞給命令的參數。

當您使用docker run您必須指定要專門運行的容器，如果您想同時運行db和web ，則應使用此命令兩次。

另一方面，當您使用docker-compose up您會運行docker-compose.yml中指定的所有容器及其所有選項。

此外， depends_on屬性僅指定一旦容器db成功啟動，將啟動容器web 。

最后，如果您希望容器能夠相互通信，您應該向撰寫文件添加一個網絡：

version: '3'
services:
  db:
    image: postgres:10
    container_name: db
    ports:
      - "5432:5432"
    volumes:
      - ./tmp/db:/var/lib/postgresql/data
    networks:
      - my-network-name

  web:
    build: .
    container_name: web
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/paper_scammer_docker
    ports:
      - "3000:3000"
    links:
      - "db:db"
    depends_on:
      - db
    networks:
      - my-network-name

networks:
  my-network-name:
    driver: bridge

添加用於引用它們的container_name也是一個好習慣。

有了這些選項，容器現在可以使用它們的名稱作為 IP/主機名進行通信：

http://<container_name>:<port>

例如，容器web將能夠像這樣連接到db容器中的db ：

http://db:5432/gnpsllco_paper_scammer

注意 IP/主機名現在是容器的名稱。

正如@LinSel 所指出的，您可以使用以下命令構建和運行所有容器（不需要 sudo）：

docker-compose up -d --build