django - docker-compose + django + redis - 错误 111 连接到 127.0.0.1 :6379. 连接被拒绝

Question

我已经查看了 this answer并且无法弄清楚如何将其应用于我的问题，因此如果有答案，将不胜感激。

我也是 docker 和 docker-compose 的菜鸟。

我有一个简单的 docker-compose.yml

version: '3'

services:
  redis:
    image: "redis:alpine"
  web:
    build: . # current directory
    command: bash -c "python /app/src/manage.py migrate && 
                      python /app/src/manage.py runserver 0.0.0.0:8000"
    volumes: 
      - .:/app
    ports:
      - "8000:8000"

当我运行它时:docker-compose up 一切正常:

$ docker-compose up
Starting hackerspace_redis_1 ... 
Starting hackerspace_redis_1 ... done
Starting hackerspace_web_1 ... 
Starting hackerspace_web_1 ... done
Attaching to hackerspace_redis_1, hackerspace_web_1
redis_1  | 1:C 19 Jul 2019 16:49:10.644 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 19 Jul 2019 16:49:10.644 # Redis version=5.0.5, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 19 Jul 2019 16:49:10.644 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1  | 1:M 19 Jul 2019 16:49:10.645 * Running mode=standalone, port=6379.
redis_1  | 1:M 19 Jul 2019 16:49:10.645 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
redis_1  | 1:M 19 Jul 2019 16:49:10.645 # Server initialized
redis_1  | 1:M 19 Jul 2019 16:49:10.645 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
redis_1  | 1:M 19 Jul 2019 16:49:10.645 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
redis_1  | 1:M 19 Jul 2019 16:49:10.645 * DB loaded from disk: 0.000 seconds
redis_1  | 1:M 19 Jul 2019 16:49:10.645 * Ready to accept connections
web_1    | Operations to perform:
web_1    |   Apply all migrations: account, admin, announcements, auth, badges, comments, contenttypes, courses, django_summernote, djconfig, djcytoscape, flatpages, notifications, portfolios, prerequisites, profile_manager, quest_manager, sessions, sites, socialaccount, suggestions, utilities
web_1    | Running migrations:
web_1    |   No migrations to apply.
web_1    | Performing system checks...
web_1    | 
web_1    | System check identified no issues (0 silenced).
web_1    | July 19, 2019 - 09:49:16
web_1    | Django version 2.0.13, using settings 'hackerspace_online.settings'
web_1    | Starting development server at http://0.0.0.0:8000/
web_1    | Quit the server with CONTROL-C.

我可以通过浏览器在 127.0.0.0:8000 访问我的 django 应用程序。但是，当我尝试登录应用程序时，我得到:

ConnectionError at /accounts/login/

Error 111 connecting to 127.0.0.1:6379. Connection refused.

这是我在 Django 设置中连接到 Redis 的方式:

REDIS_HOST = os.environ.get('REDIS_HOST', '127.0.0.1')
REDIS_PORT = os.environ.get('REDIS_PORT', '6379')

CACHES = {
    "default": {
        "BACKEND": "django_redis.cache.RedisCache",
        "LOCATION": "redis://{}:{}/1".format(REDIS_HOST, REDIS_PORT),
        "OPTIONS": {
            "CLIENT_CLASS": "django_redis.client.DefaultClient",
        }
    },
    #...
}

如何让我的 Django 应用程序连接到 Redis 容器？

请注意，据我所知，没有其他使用端口 6379(通过 sudo lsof -i -P -n | grep LISTEN)

Answer 1

127.0.0.1 在 Docker 中几乎总是表示“这个容器”。如果您在 Docker Compose 下运行您的应用程序, 它

... sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name.

也就是说，在这个 docker-compose.yml 文件的上下文中，有主机名 redis 和 web 指向两个容器。

您已经完成了一项重要的配置工作。当你的代码说

REDIS_HOST = os.environ.get('REDIS_HOST', '127.0.0.1')

您可以设置一个覆盖内置默认值的环境变量。所以在这里你只需要在你的 docker-compose.yml 文件中添加一个环境变量设置:

version: '3'
services:
  redis:
    image: "redis:alpine"
  web:
    build: . # current directory
    environment:
      - REDIS_HOST=redis
    ports:
      - "8000:8000"
    # application source code and default command are built into the image