我不知道如何从我的app服务连接到我的redis服务。使用DDocker版本18.03.1-ce，构建9 ee 9 f40 ocker for Mac。
我试着把我在类似问题上发现的各种方法联系起来：

const client = redis.createClient({ host: 'localhost', port: 6379});

const client = redis.createClient({ host: 'redis', port: 6379});

const client = redis.createClient('redis://redis:6379');

const client = redis.createClient('redis', 6379); // and reversed args

我总是得到某种形式的：
错误：Redis连接到localhost：6379失败-连接ECONNREFUSED 127.0.0.1:6379
错误：Redis连接到redis：6379失败-连接ECONNREFUSED 172.20.0.2:6379

Docker容器

$ docker ps
CONTAINER ID        IMAGE                COMMAND                  CREATED              STATUS              PORTS                    NAMES
0fd798d58561        app_app         "pm2-runtime start e…"   2 seconds ago        Up 7 seconds                                 app
65d148e498f7        app_redis       "docker-entrypoint.s…"   About a minute ago   Up 8 seconds        0.0.0.0:6379->6379/tcp   redis

Redis工作原理：

$ docker exec -it redis /bin/bash
root@65d148e498f7:/data# redis-cli ping
PONG

Redis Dockerfile（非常简单）

FROM redis:4.0.9
COPY redis.conf /usr/local/etc/redis/redis.conf
CMD ["redis-server", "/usr/local/etc/redis/redis.conf"]

app Dockerfile

FROM node:10.3.0-slim
RUN mkdir -p /app
COPY src/* /app/
CMD ["pm2-runtime", "start", "/app/ecosystem.config.js"]

docker-compose.yml

version: "3"
services:
  redis:
    build: ./redis/
    container_name: redis
    restart: unless-stopped
    ports:
      - "6379:6379"
    expose:
      - "6379"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      - 'API_PORT=6379'
      - 'NODE_ENV=production'
  app:
    depends_on:
      - redis
    build: ./app/
    container_name: app
    restart: unless-stopped
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /app/node_modules
    environment:
      - 'NODE_ENV=production'