docker-compose + django + redis - 连接到 127.0.0.1:6379 时出现错误 111。连接被拒绝

我已经看过了这个答案并且不知道如何将其应用于我的问题，所以如果答案存在，我们将不胜感激。

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"

当我运行这个时：docker-compose up一切似乎都很好：

$ 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.

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

/accounts/login/ 处的连接错误

连接到 127.0.0.1:6379 时出现错误 111。连接被拒绝。

以下是我在 django 设置中连接到 redis 的方法：

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，没有其他任何东西使用端口 6379（通过sudo lsof -i -P -n | grep LISTEN)

127.0.0.1Docker 中几乎总是意味着“这个容器”。如果您正在运行您的应用程序Docker 组合, it

...为您的应用程序设置一个网络。服务的每个容器都会加入默认网络，并且都是可达的通过该网络上的其他容器，以及可发现的由它们使用与容器名称相同的主机名。

也就是说，在这个背景下docker-compose.yml文件中，有主机名redis and web那个点在两个容器上。

您已经完成了其中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')

您可以设置一个环境变量来覆盖内置默认值。所以这里你只需要添加一个环境变量设置到你的docker-compose.yml file:

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