Docker技术入门与实战 第二版-学习笔记-9-Docker Compose 项目-3-Django项目实例

使用 Django
我们现在将使用 Compose 配置并运行一个 Django/PostgreSQL 应用。在此之前，先确保 Compose 已经安装。

1.通过编辑 Dockerfile文件来指定 Docker 容器要安装内容:

FROM python:2.7
ENV PYTHONUNBUFFERED
RUN mkdir /code
WORKDIR /code
ADD requirements.txt /code/
RUN pip install -r requirements.txt
ADD . /code/

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

2.在 requirements.txt文件里面写明需要安装的具体依赖包名:

Django
psycopg2

3.构建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:

db:
  image: postgres //db服务使用的镜像
web:
  build: . //即本地的Dockerfile文件
  command: python manage.py runserver 0.0.0.0: //容器启动时运行的命令
  volumes:
    - .:/code //挂载的数据卷
  ports:
    - "8000:8000" //映射的端口
  links: //连接的db容器
    - db

4.然后就可以使用 docker-compose run命令启动一个 Django 应用了

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下面的指令

userdeMacBook-Pro:django user$ docker-compose run web django-admin.py startproject docker_composeexample .
Starting django_db_1 ... done

然后就会生成下面红圈圈起来的部分文件和文件夹：

5.开始使用该Django：

1）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 docker_composeexample/settings.py文件中 DATABASES = ...定义的节点内容:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'postgres',
        'USER': 'postgres',
        'HOST': 'db',
        'PORT': ,
    }
}

这些信息是在 postgres Docker 镜像固定设置好的。 然后，运行 docker-compose up：

userdeMacBook-Pro:django user$ docker-compose up
django_db_1 is up-to-date
Starting django_web_1 ... done
Attaching to django_db_1, django_web_1
db_1   | The files belonging to this database system will be owned by user "postgres".
db_1   | This user must also own the server process.
db_1   |
db_1   | The database cluster will be initialized with locale "en_US.utf8".
db_1   | The default database encoding has accordingly been set to "UTF8".
db_1   | The default text search configuration will be set to "english".
db_1   |
db_1   | Data page checksums are disabled.
db_1   |
db_1   | fixing permissions on existing directory /var/lib/postgresql/data ... ok
db_1   | creating subdirectories ... ok
db_1   | selecting default max_connections ...
db_1   | selecting default shared_buffers ... 128MB
db_1   | selecting dynamic shared memory implementation ... posix
db_1   | creating configuration files ... ok
db_1   | running bootstrap script ... ok
db_1   | performing post-bootstrap initialization ... ok
db_1   |
db_1   | WARNING: enabling "trust" authentication for local connections
db_1   | You can change this by editing pg_hba.conf or using the option -A, or
db_1   | --auth-local and --auth-host, the next time you run initdb.
db_1   | syncing data to disk ... ok
db_1   |
db_1   | Success. You can now start the database server using:
db_1   |
db_1   |     pg_ctl -D /var/lib/postgresql/data -l logfile start
db_1   |
db_1   | ****************************************************
db_1   | WARNING: No password has been set for the database.
db_1   |          This will allow anyone with access to the
db_1   |          Postgres port to access your database. In
db_1   |          Docker's default configuration, this is
db_1   |          effectively any other container on the same
db_1   |          system.
db_1   |
db_1   |          Use "-e POSTGRES_PASSWORD=password" to set
db_1   |          it in "docker run".
db_1   | ****************************************************
db_1   | waiting for server to start....-- ::34.186 UTC [] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1   | -- ::34.202 UTC [] LOG:  database system was shut down at -- :: UTC
db_1   | -- ::34.207 UTC [] LOG:  database system is ready to accept connections
db_1   |  done
db_1   | server started
db_1   |
db_1   | /usr/local/bin/docker-entrypoint.sh: ignoring /docker-entrypoint-initdb.d/*
db_1   |
db_1   | waiting for server to shut down....2018-12-17 10:29:34.279 UTC [45] LOG:  received fast shutdown request
db_1   | 2018-12-17 10:29:34.282 UTC [45] LOG:  aborting any active transactions
db_1   | 2018-12-17 10:29:34.284 UTC [45] LOG:  background worker "logical replication launcher" (PID 52) exited with exit code 1
db_1   | 2018-12-17 10:29:34.285 UTC [47] LOG:  shutting down
db_1   | 2018-12-17 10:29:34.302 UTC [45] LOG:  database system is shut down
db_1   |  done
db_1   | server stopped
db_1   |
db_1   | PostgreSQL init process complete; ready for start up.
db_1   |
db_1   | 2018-12-17 10:29:34.392 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
db_1   | 2018-12-17 10:29:34.392 UTC [1] LOG:  listening on IPv6 address "::", port 5432
db_1   | 2018-12-17 10:29:34.395 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
db_1   | 2018-12-17 10:29:34.407 UTC [54] LOG:  database system was shut down at 2018-12-17 10:29:34 UTC
db_1   | 2018-12-17 10:29:34.412 UTC [1] LOG:  database system is ready to accept connections
web_1  | /usr/local/lib/python2.7/site-packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
web_1  |   """)
web_1  | /usr/local/lib/python2.7/site-packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
web_1  |   """)
web_1  | Performing system checks...
web_1  |
web_1  | System check identified no issues (0 silenced).
web_1  |
web_1  | You have 13 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.
web_1  | Run 'python manage.py migrate' to apply them.
web_1  | December 17, 2018 - 11:03:22
web_1  | Django version 1.11.17, using settings 'docker_composeexample.settings'
web_1  | Starting development server at http://0.0.0.0:8000/
web_1  | Quit the server with CONTROL-C.

这个 web 应用已经开始在你的 docker 守护进程里监听着 5000 端口了(如果你有使用 boot2docker ，执行 boot2docker ip，就会看到它的地址)。

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，在另外一个终端运行以下命令即可:

userdeMacBook-Pro:django user$ docker-compose run web python manage.py syncdb
Starting django_db_1 ... done
/usr/local/lib/python2./site-packages/psycopg2/__init__.py:: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
  """)
Unknown command: 'syncdb'
Type 'manage.py help' for usage.

错误原因：在Django 1.9及未来的版本种使用migrate代替syscdb，所以将syscdb改为migrate即可：

userdeMacBook-Pro:django user$ docker-compose run web python manage.py migrate
Starting django_db_1 ... done
/usr/local/lib/python2./site-packages/psycopg2/__init__.py:: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
  """)
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying sessions.0001_initial... OK