Redis service: "cache:6379" Name or service not known

Drone Support
1

Hi:

We try to running Redis service for application testing in build process, however, something wrong when application try to connect to Redis, from below code section, all steps works fine except “ping redis in docker”, the main different for this step is we build a py file to docker, and run it to get/set data from Redis, but it shows up error message like "redis.exceptions.ConnectionError: Error -2 connecting to cache:6379. Name or service not known."

Does anyone have idea about how to proceeding this? thanks

.drone.yml

kind: pipeline
name: App-report

platform:
  os: linux
  arch: amd64
 
steps:
  - name: ping redis
    image: redis
    commands:
    - sleep 5
    - redis-cli -h cache ping
    - redis-cli -h cache set FOO bar
    - redis-cli -h cache get FOO

  - name: ping mongo
    image: mongo:3
    commands:
    - sleep 5
    - mongo --host mongo --eval "db.version()"

  - name: ping pyredis
    image: python:3.7-slim
    commands:
      - pip3 install redis
      - python3 test_redis.py

  - name: ping redis in docker
    image: docker:dind
    volumes:
      - name: dockersock
        path: /var/run
    commands:
      - docker build -t myredis-docker -f redis_Dockerfile .
      - docker run -itd --rm --name myredis-docker myredis-docker
      - docker logs -f myredis-docker
      - docker stop myredis-docker

services:
  - name: docker
    image: docker:dind
    privileged: true
    volumes:
    - name: dockersock
      path: /var/run

  - name: cache
    image: redis
    ports:
      - 6379
  - name: mongo
    image: mongo:3
    command: [ --smallfiles ]
    ports:
      - 27017

volumes:
  - name: dockersock
    temp: {}

test_redis.py

import redis

if __name__ == '__main__':
    r = redis.from_url('redis://cache')
    print (r.ping())
    print (r.get('FOO'))
    print (r.set('z', 'xyz'))
    print (r.get('z'))

redis_Dockerfile

FROM python:3.7-slim
ADD test_redis.py /
RUN pip install redis
CMD [ "python", "./test_redis.py" ]
2

Hi, just an update to let you guys know this version works as follows:

steps:
  - name: ping redis in docker
    image: docker:dind
    volumes:
      - name: docker_sock
        path: /var/run/docker.sock
    commands:
      - docker build -t myredis-docker -f redis_Dockerfile .
      - docker run -itd --rm --name myredis-docker myredis-docker
      - docker logs -f myredis-docker
      - docker stop myredis-docker

services:
  - name: cache
    image: redis
    ports:
      - 6379
  - name: mongo
    image: mongo:3
    command: [ --smallfiles ]
    ports:
      - 27017

volumes:
  - name: docker_sock
    host:
      path: /var/run/docker.sock

Does anyone have any idea about the root cause? thanks