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ERROR: In file './docker-compose.yml', service must be a mapping, not a NoneType

Hi, I am trying to use the example provided in the site https://docs.docker.com/compose/gettingstarted/

Step 3: Define services Define a set of services using docker-compose.yml:

Create a file called docker-compose.yml in your project directory and add the following:

version: '2'
services:
  web:
    build: .
    ports:
     - "5000:5000"
    volumes:
     - .:/code
    depends_on:
     - redis
  redis:
    image: redis

and when I run the command docker-compose up i got the below error

ERROR: yaml.scanner.ScannerError: while scanning for the next token found character ‘\t’ that cannot start any token in “./docker-compose.yml”, line 18, column 1 so i removed all spaces and modified it as below

Defines two web services, web and redis

version: ‘2’ services: web: build: . #Build from the dockerfile from current dir ports:

  • “5000:5000” #Forward the exposed port 5000 on the container to port 5000 on the host machine volumes:
  • .:/code #Mounts the project directory on the host to /code inside the container directory allowing you to modify the code without having to rebuild the image depends_on:
  • redis redis: image: redis #Links the webservice to the redis service

on trying it again i am getting an error now as

docker-compose up ERROR: In file ‘./docker-compose.yml’, service must be a mapping, not a NoneType.

Can I get some help what is wrong here… I am using MAC.

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i got the right file

version: ‘2’ services: web: build: . ports: - “5000:5000” volumes: - .:/code - logvolume01:/var/log links: - redis redis: image: redis volumes: logvolume01: {}

This is working … can refer the following link

https://docs.docker.com/compose/overview/ :)


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This question was answered by @VVP:

i got the right file

version: ‘2’ services: web: build: . ports:

  • “5000:5000” volumes:
  • .:/code
  • logvolume01:/var/log links:
  • redis redis: image: redis volumes: logvolume01: {}

This is working … can refer the following link

https://docs.docker.com/compose/overview/ :)

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