## 使用 Django
本小节内容适合 `Python` 开发人员阅读。
我们现在将使用 `Docker Compose` 配置并运行一个 `Django/PostgreSQL` 应用。
在一切工作开始前,需要先编辑好三个必要的文件。
第一步,因为应用将要运行在一个满足所有环境依赖的 Docker 容器里面,那么我们可以通过编辑 `Dockerfile` 文件来指定 Docker 容器要安装内容。内容如下:
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">FROM python</span><span class="pun">:</span><span class="lit">3</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">ENV PYTHONUNBUFFERED </span><span class="lit">1</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">RUN mkdir </span><span class="pun">/</span><span class="pln">code</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">WORKDIR </span><span class="pun">/</span><span class="pln">code</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">ADD requirements</span><span class="pun">.</span><span class="pln">txt </span><span class="pun">/</span><span class="pln">code</span><span class="pun">/</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">RUN pip install </span><span class="pun">-</span><span class="pln">r requirements</span><span class="pun">.</span><span class="pln">txt</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">ADD </span><span class="pun">.</span><span class="pln"> </span><span class="pun">/</span><span class="pln">code</span><span class="pun">/</span></code></li>
</ol>
```
以上内容指定应用将使用安装了 Python 以及必要依赖包的镜像。更多关于如何编写 `Dockerfile` 文件的信息可以查看 [镜像创建](%24image-create.md#%E5%88%A9%E7%94%A8%20Dockerfile%20%E6%9D%A5%E5%88%9B%E5%BB%BA%E9%95%9C%E5%83%8F) 和 [ Dockerfile 使用](%24dockerfile-README.md)。
第二步,在 `requirements.txt` 文件里面写明需要安装的具体依赖包名。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="typ">Django</span><span class="pun">>=</span><span class="lit">1.8</span><span class="pun">,<</span><span class="lit">2.0</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">psycopg2</span></code></li>
</ol>
```
第三步,`docker-compose.yml` 文件将把所有的东西关联起来。它描述了应用的构成(一个 web 服务和一个数据库)、使用的 Docker 镜像、镜像之间的连接、挂载到容器的卷,以及服务开放的端口。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">version</span><span class="pun">:</span><span class="pln"> </span><span class="str">"3"</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">services</span><span class="pun">:</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> db</span><span class="pun">:</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> image</span><span class="pun">:</span><span class="pln"> postgres</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> web</span><span class="pun">:</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> build</span><span class="pun">:</span><span class="pln"> </span><span class="pun">.</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> command</span><span class="pun">:</span><span class="pln"> python3 manage</span><span class="pun">.</span><span class="pln">py runserver </span><span class="lit">0.0</span><span class="pun">.</span><span class="lit">0.0</span><span class="pun">:</span><span class="lit">8000</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> volumes</span><span class="pun">:</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="pun">-</span><span class="pln"> </span><span class="pun">.:/</span><span class="pln">code</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> ports</span><span class="pun">:</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="pun">-</span><span class="pln"> </span><span class="str">"8000:8000"</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> links</span><span class="pun">:</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="pun">-</span><span class="pln"> db</span></code></li>
</ol>
```
查看 [`docker-compose.yml` 章节](%24yml_ref.md) 了解更多详细的工作机制。
现在我们就可以使用 `docker-compose run` 命令启动一个 `Django` 应用了。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">$ docker</span><span class="pun">-</span><span class="pln">compose run web django</span><span class="pun">-</span><span class="pln">admin</span><span class="pun">.</span><span class="pln">py startproject django_example </span><span class="pun">.</span></code></li></ol>
```
Compose 会先使用 `Dockerfile` 为 web 服务创建一个镜像,接着使用这个镜像在容器里运行 `django-admin.py startproject composeexample` 指令。
这将在当前目录生成一个 `Django` 应用。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">$ ls</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="typ">Dockerfile</span><span class="pln"> docker</span><span class="pun">-</span><span class="pln">compose</span><span class="pun">.</span><span class="pln">yml django_example manage</span><span class="pun">.</span><span class="pln">py requirements</span><span class="pun">.</span><span class="pln">txt</span></code></li>
</ol>
```
如果你的系统是 Linux,记得更改文件权限。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">sudo chown </span><span class="pun">-</span><span class="pln">R $USER</span><span class="pun">:</span><span class="pln">$USER </span><span class="pun">.</span></code></li></ol>
```
首先,我们要为应用设置好数据库的连接信息。用以下内容替换 `django_example/settings.py` 文件中 `DATABASES = ...` 定义的节点内容。
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">DATABASES </span><span class="pun">=</span><span class="pln"> </span><span class="pun">{</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'default'</span><span class="pun">:</span><span class="pln"> </span><span class="pun">{</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'ENGINE'</span><span class="pun">:</span><span class="pln"> </span><span class="str">'django.db.backends.postgresql'</span><span class="pun">,</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'NAME'</span><span class="pun">:</span><span class="pln"> </span><span class="str">'postgres'</span><span class="pun">,</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'USER'</span><span class="pun">:</span><span class="pln"> </span><span class="str">'postgres'</span><span class="pun">,</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'HOST'</span><span class="pun">:</span><span class="pln"> </span><span class="str">'db'</span><span class="pun">,</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="str">'PORT'</span><span class="pun">:</span><span class="pln"> </span><span class="lit">5432</span><span class="pun">,</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln"> </span><span class="pun">}</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pun">}</span></code></li>
</ol>
```
这些信息是在 [postgres](https://store.docker.com/images/postgres/) 镜像固定设置好的。然后,运行 `docker-compose up` :
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">$ docker</span><span class="pun">-</span><span class="pln">compose up</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">django_db_1 is up</span><span class="pun">-</span><span class="pln">to</span><span class="pun">-</span><span class="pln">date</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="typ">Creating</span><span class="pln"> django_web_1 </span><span class="pun">...</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="typ">Creating</span><span class="pln"> django_web_1 </span><span class="pun">...</span><span class="pln"> </span><span class="kwd">done</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="typ">Attaching</span><span class="pln"> to django_db_1</span><span class="pun">,</span><span class="pln"> django_web_1</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">The</span><span class="pln"> files belonging to this database system will be owned by user </span><span class="str">"postgres"</span><span class="pun">.</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">This</span><span class="pln"> user must also own the server process</span><span class="pun">.</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">The</span><span class="pln"> database cluster will be initialized with locale </span><span class="str">"en_US.utf8"</span><span class="pun">.</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">The</span><span class="pln"> default database encoding has accordingly been </span><span class="kwd">set</span><span class="pln"> to </span><span class="str">"UTF8"</span><span class="pun">.</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">db_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">The</span><span class="pln"> default text search configuration will be </span><span class="kwd">set</span><span class="pln"> to </span><span class="str">"english"</span><span class="pun">.</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">Performing</span><span class="pln"> system checks</span><span class="pun">...</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">System</span><span class="pln"> check identified no issues </span><span class="pun">(</span><span class="lit">0</span><span class="pln"> silenced</span><span class="pun">).</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">November</span><span class="pln"> </span><span class="lit">23</span><span class="pun">,</span><span class="pln"> </span><span class="lit">2017</span><span class="pln"> </span><span class="pun">-</span><span class="pln"> </span><span class="lit">06</span><span class="pun">:</span><span class="lit">21</span><span class="pun">:</span><span class="lit">19</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">Django</span><span class="pln"> version </span><span class="lit">1.11</span><span class="pun">.</span><span class="lit">7</span><span class="pun">,</span><span class="pln"> using settings </span><span class="str">'django_example.settings'</span></code></li>
<li class="l1"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">Starting</span><span class="pln"> development server at http</span><span class="pun">://</span><span class="lit">0.0</span><span class="pun">.</span><span class="lit">0.0</span><span class="pun">:</span><span class="lit">8000</span><span class="pun">/</span></code></li>
<li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">web_1 </span><span class="pun">|</span><span class="pln"> </span><span class="typ">Quit</span><span class="pln"> the server with CONTROL</span><span class="pun">-</span><span class="pln">C</span><span class="pun">.</span></code></li>
</ol>
```
这个 `Django` 应用已经开始在你的 Docker 守护进程里监听着 `8000` 端口了。打开 `127.0.0.1:8000` 即可看到 `Django` 欢迎页面。
你还可以在 Docker 上运行其它的管理命令,例如对于同步数据库结构这种事,在运行完 `docker-compose up` 后,在另外一个终端进入文件夹运行以下命令即可:
```
<pre class="prettyprint"><ol class="linenums"><li class="l"><code class="pcalibre10 pcalibre11 pcalibre9"><span class="pln">$ docker</span><span class="pun">-</span><span class="pln">compose run web python manage</span><span class="pun">.</span><span class="pln">py syncdb</span></code></li></ol>
```
- 致谢
- 目录
- 01. 前言
- 02. 修订记录
- 03. 如何贡献
- 04. Docker 简介
- 什么是 Docker
- 为什么要用 Docker
- 05. 基本概念
- 镜像
- 容器
- 仓库
- 06. 安装 Docker
- Ubuntu
- Debian
- CentOS
- Raspberry Pi
- macOS
- Windows PC
- 镜像加速器
- 07.使用镜像
- 获取镜像
- 列出镜像
- 删除本地镜像
- 利用 commit 理解镜像构成
- 使用 Dockerfile 定制镜像
- Dockerfile 指令详解
- COPY 复制文件
- ADD 更高级的复制文件
- CMD 容器启动命令
- ENTRYPOINT 入口点
- ENV 设置环境变量
- ARG 构建参数
- VOLUME 定义匿名卷
- EXPOSE 暴露端口
- WORKDIR 指定工作目录
- USER 指定当前用户
- HEALTHCHECK 健康检查
- ONBUILD 为他人作嫁衣裳
- 参考文档
- Dockerfile 多阶段构建
- 其它制作镜像的方式
- 实现原理
- 08. 操作容器
- 启动
- 守护态运行
- 终止
- 进入容器
- 导出和导入
- 删除
- 09. 访问仓库
- Docker Hub
- 私有仓库
- 私有仓库高级配置
- 10. 数据管理
- 数据卷
- 监听主机目录
- 11. 使用网络
- 外部访问容器
- 容器互联
- 配置 DNS
- 12. 高级网络配置
- 快速配置指南
- 容器访问控制
- 配置 docker0 网桥
- 自定义网桥
- 工具和示例
- 编辑网络配置文件
- 实例:创建一个点到点连接
- 映射容器端口到宿主主机的实现
- 13. Docker 三剑客之 Compose 项目
- 简介
- 安装与卸载
- 使用
- 命令说明
- Compose 模板文件
- 实战 Django
- 实战 Rails
- 实战 WordPress
- 14. Docker 三剑客之 Machine 项目
- 安装
- 使用
- 15. Docker 三剑客之 Docker Swarm
- 16. Swarm mode
- 基本概念
- 创建 Swarm 集群
- 部署服务
- 使用 compose 文件
- 管理敏感数据
- 管理配置信息
- 17. 安全
- 内核命名空间
- 控制组
- 服务端防护
- 内核能力机制
- 其它安全特性
- 总结
- 18. 底层实现
- 基本架构
- 命名空间
- 控制组
- 联合文件系统
- 容器格式
- 网络
- 19. Etcd 项目
- 简介
- 安装
- 集群
- 使用 etcdctl
- 使用 etcdctl v2
- 20. CoreOS 项目
- 简介
- 工具
- 快速搭建 CoreOS 集群
- 21. Kubernetes 项目
- 简介
- 快速上手
- 基本概念
- kubectl 使用
- 架构设计
- 22. Mesos - 优秀的集群资源调度平台
- Mesos 简介
- 安装与使用
- 原理与架构
- Mesos 配置项解析
- 日志与监控
- 常见应用框架
- 本章小结
- 23. 容器与云计算
- 简介
- 亚马逊云
- 腾讯云
- 阿里云
- 小结
- 24. 实战案例-操作系统
- Busybox
- Alpine
- Debian Ubuntu
- CentOS Fedora
- 本章小结
- 25. 实战案例-CI-CD
- Drone
- 26. Docker 开源项目
- LinuxKit
- 27. 附录
- 附录一:常见问题总结
- 附录二:热门镜像介绍
- Ubuntu
- CentOS
- MySQL
- MongoDB
- Redis
- Nginx
- WordPress
- Node.js
- 附录三:Docker 命令查询
- 附录四:Dockerfile 最佳实践
- 附录五:资源链接
- 附录六:Docker 中文资源