如何将环境变量传递给docker中的nginx.conf文件？

Question

我正在尝试使用 docker 在 Rails 上设置 ruby​​，一切都很好，但我希望在通过 docker-compose 命令构建映像期间将动态域作为环境变量传递给 nginx.conf 文件，但我不知道该怎么做。我尝试使用此命令 Docker-compose build dcoker-compose up

Docker 文件

FROM ruby:2.7.2
ENV RAILS_ROOT /var/www/quickcard
ENV BUNDLE_VERSION 2.1.4
ENV BUNDLE_PATH usr/local/bundle/gems
ENV RAILS_LOG_TO_STDOUT true
ENV RAILS_PORT 5000
COPY ./entrypoint.sh /usr/local/bin/entrypoint.sh
RUN chmod +x /usr/local/bin/entrypoint.sh
RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
RUN apt-get update -qq && apt-get install -y build-essential \
git \
libxml2-dev \
libpq-dev \
libxslt-dev \
nodejs \
yarn \
imagemagick \
tzdata \
less \
cron \
&& rm -rf /var/cache/apk/*
RUN gem install bundler --version "$BUNDLE_VERSION"
RUN mkdir -p $RAILS_ROOT
WORKDIR $RAILS_ROOT
ADD Gemfile Gemfile
ADD Gemfile.lock Gemfile.lock
COPY yarn.lock yarn.lock
RUN bundle install
EXPOSE $RAILS_PORT
RUN ln -s $RAILS_ROOT/config/systemd/puma.service /etc/systemd/system/quickcard
COPY . .
RUN crontab -l | { cat; echo ""; } | crontab -
RUN yarn install
RUN yarn install --check-files
RUN ls /var/www/quickcard/public
ENTRYPOINT ["entrypoint.sh"]
CMD ["bundle", "exec", "puma", "-C", "config/puma.rb"]

Nginx Docker 文件

FROM nginx
RUN apt-get update -qq && apt-get -y install apache2-utils
ENV RAILS_ROOT /var/www/quickcard
WORKDIR $RAILS_ROOT
RUN mkdir log
COPY public public/

COPY ./nginx.conf /etc/nginx/conf.d/default.conf
COPY ./multi_quickcard.key /etc/nginx/multi_quickcard.key
COPY ./quickcard-ssl-test.pem /etc/nginx/quickcard-ssl-test.pem

EXPOSE 80 443
CMD [ "nginx", "-g", "daemon off;" ]

Nginx.conf 例如

upstream puma {
    # Path to Puma SOCK file, as defined previously
    server app:5000 fail_timeout=0;
}

server {
    listen 80;
    server_name default_server;

    index index.html index.htm;
    try_files $uri $uri/ /index.html =404;

    location / {
        root /var/www/quickcard/public/;
        proxy_pass http://puma;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;
    }

    location /api {
        root /var/www/quickcard/public/;
        proxy_pass http://puma;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;
    }

    location ^~ /assets/ {
        root /var/www/quickcard/public/;
        gzip_static on;
        expires max;
        add_header Cache-Control public;
    }

    error_page 500 502 503 504 /500.html;
    client_max_body_size 4G;
    keepalive_timeout 10;
}

Docker 撰写文件

version: '2.2'
services:
  app:
    build: 
      context: .
      dockerfile: ./Dockerfile
    command: bash -c "bundle exec rails s -p 5000 -e production -b 0.0.0.0 &&  RAILS_ENV=production bundle exec rake assets:precompile"
    environment:
      RAILS_ENV: production
    volumes:
      - /var/wwww/quickcard
      - /var/wwww/quickcard/public
    ports:
      - 5000:5000
  sidekiq:
    build: .
    command: bundle exec sidekiq -C config/sidekiq.yml
    environment:
      RAILS_ENV: production
    volumes:
      - /var/wwww/quickcard/tmp
  cron_job:
    build: .
    command: cron -f
  nginx:
    build:
      context: .
      dockerfile: ./nginx.Dockerfile
    volumes:
      - ./log-nginx:/var/log/nginx/
    restart: always
    ports:
      - 80:80
      - 443:443

Answer 1

nginx Docker 镜像可以在启动前提取环境变量，但这有点棘手。一种解决方案是：

1. 将环境变量添加到您的nginx.conf文件中。
2. 在构建步骤中将其复制到/etc/nginx/templates/nginx.conf.template容器中（而不是普通的容器/etc/nginx）或作为卷。
3. NGINX_ENVSUBST_OUTPUT_DIR: /etc/nginx在 中设置环境变量docker-compose.yml。

这将导致nginx.conf.template文件被复制到/etc/nginxasnginx.conf并且环境变量将被替换为它们的值。

有一点需要记住：使用command属性 indocker-compose.yml似乎会禁用提取功能。如果需要运行自定义命令来启动 nginx，可以使用 Dockerfile 版本。

我创建了一个具有完整设置的存储库，但以防万一它不可用：

# docker-compose.yml

version: "3"
services:
  nginx-no-dockerfile:
    container_name: nginx-no-dockerfile
    image: nginx:1.23.1-alpine
    ports:
      - 8081:80
    volumes:
      - ./site/index.html:/usr/share/nginx/html/index.html
      - ./site/nginx.conf:/etc/nginx/templates/nginx.conf.template
    working_dir: /usr/share/nginx/html
    environment:
      NGINX_ENVSUBST_OUTPUT_DIR: /etc/nginx
      API_URL: http://example.com


  nginx-with-dockerfile:
    container_name: nginx-with-dockerfile
    build:
      context: ./site
      dockerfile: ./Dockerfile
    ports:
      - 8082:80
    volumes:
      - ./site/index.html:/usr/share/nginx/html/index.html
    environment:
      NGINX_ENVSUBST_OUTPUT_DIR: /etc/nginx
      API_URL: http://example.com

# site/nginx.conf

worker_processes auto;

events {
}

http {
  include /etc/nginx/mime.types;

  server {
    listen 80;

    root /usr/share/nginx/html;
    index index.html index.htm;

    location / {
      try_files $uri $uri/ /index.html;
    }

    location /example {
      proxy_pass $API_URL;
    }
  }
}

# site/Dockerfile

FROM nginx:1.23.1-alpine

WORKDIR /usr/share/nginx/html
COPY ./nginx.conf /etc/nginx/templates/nginx.conf.template

EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

运行无 Dockerfile 版本：docker compose up nginx-no-dockerfile

运行 Dockerfile 版本：

docker compose build nginx-with-dockerfile
docker compose up nginx-with-dockerfile

确保站点文件夹中也有index.html 文件。

Answer 2

Nginx 推荐的方法似乎是使用 envsubst 实用程序。您需要创建一个模板文件，并将变量放置在 as$Variable或内{Variable}。然后，您可以将模板文件传递给 envsubst，该文件将从环境中呈现变量。

这有一些缺点，因为它可能会无意中替换 nginx 变量，因此我会确保传递您想要替换的特定变量。

有关更多详细信息，请参阅解决类似问题的此问题：https://serverfault.com/questions/577370/how-can-i-use-environment-variables-in-nginx-conf