python - docker 无法从文件连接到 redis

Question

我正在使用 docker-compose up 运行 docker。

在一个文件中，我试图访问使用以下方法创建的 redis:

import redis

pool = redis.ConnectionPool(host='redis', port=6379, db=0)
r = redis.Redis(connection_pool=pool)
r.flushall()

这是我的 docker-compose.yml redis 部分:

web:
  build: .
  ports:
   - "8000:8000"
  links:
   - db
   - redis
  environment:
    - DATABASE_URL=postgres://user:openhouse2016@db:5432/chat
    - REDIS_URL=redis://redis:6379/1
  volumes:
    - .:/opt/app
db:
  image: praiskup/postgresql:APIv1.0.1-fedora23
#  volumes:
#   - ./db:/var/lib/pgsql/data
  environment:
   - POSTGRESQL_DATABASE=chat
   - POSTGRESQL_USER=user
   - POSTGRESQL_PASSWORD=openhouse2016
   - POSTGRESQL_CONTAINER_OPTS=assert_external_data = false
worker:
  build: .
  environment:
    - DATABASE_URL=postgres://user:openhouse2016@db:5432/chat
    - REDIS_URL=redis://redis:6379/1
  links:
   - db
   - redis
  volumes:
    - .:/opt/app
  # we need to wait for database setup
  command: bash -c "sleep 7 && exec python /opt/app/channels-example/manage.py runworker -v3"
redis:
  image: redis
  ports:
        - "6379:6379"
migrator:
  build: .
  environment:
   - DATABASE_URL=postgres://user:openhouse2016@db:5432/chat
   - REDIS_URL=redis://redis:6379/1
  links:
   - db
  # it indeed takes this long to start the database
  command: bash -c "sleep 5 && exec python /opt/app/channels-example/manage.py migrate"

运行后:

docker-compose down
docker-compose build
docker-compose up

一切运行良好，redis 表示它已准备好接受端口 6379 上的连接。

但是，上面的 python 代码生成:

redis.exceptions.ConnectionError: Error -5 connecting to redis:6379. No address associated with hostname.

如何从 python 文件连接到 redis？

编辑:

docker ps -a

redis 显示:

3a494c9da73d     redis        "docker-entrypoint.sh" 
10 seconds ago   Up 9 seconds  0.0.0.0:6379->6379/tcp

Answer 1

迁移器没有链接到 redis。这修复了它:

migrator:
  build: .
  environment:
   - DATABASE_URL=postgres://user:openhouse2016@db:5432/chat
   - REDIS_URL=redis://redis:6379/1
  links:
   - db
   - redis #this line here was missing
  # it indeed takes this long to start the database
  command: bash -c "sleep 5 && exec python /opt/app/channels-example/manage.py migrate"