docker-compose error what is this?

Question

I want to docker-compose up this file:

identidock:
build: .
ports:
 - "5000:5000"
environment:
ENV: DEV
volumes:
 - ./app:/app

but it has a error:

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

What should i do?

Answer 1

From the error message I guess the content of the docker-compose.yml file is not properly formatted as YAML.

Make it look like this (keep the leading spaces on all lines) and it will work; or, at least, you will encounter a different type of error:

identidock:
  build: .
  ports:
    - "5000:5000"
  environment:
    ENV: DEV
  volumes:
    - ./app:/app