docker-compose.yaml won't parse

Question

I am having trouble with running my docker-compose.yml. I have retrieved a pre-made docker-compose file from a github page and customized it to my needs. When trying to parse it, it returns errors.

I am not very schooled in yaml syntax, so it is difficult for me to understand where the error stems from.

The code from the docker-compose.yml file is posted on this pastebin: https://pastebin.com/XjM2S11i

The following errors are returned when parsing:

ERROR:

while parsing a block mapping
  in "<unicode string>", line 5, column 1:
    version: "3.6"
    ^
expected <block end>, but found '<block mapping start>'
  in "<unicode string>", line 149, column 3:
      watchtower:
      ^

Can anyone help me fix the syntax/indentation? Would be much appreciated.

Answer 1

In your file you have (line 115):

phpmyadmin:
    hostname: phpmyadmin

So the value for the key phpmyadmin of your root level mapping is a mapping itself which starts of with a key hostname which is indented four positions.

Then on line 149 you have:

  watchtower:
    container_name: watchtower

which is only indented two positions. You'll have to decide what is the parent node of watchtower : either it is a key for the root level mapping and then it needs to be flush left or it is a key in the same mapping that hostname is a key in and then it needs to be indented four positions. Or that there needs to be a key inserted at the root level mapping before watchtower .

I strongly recommend always to use number of two positions indentation for both mapping values and sequence items (and that implies no offset for the sequence item indicator):

a:
  b:
  - 1
  - 2

Your docker-compose YAML file is a hodgepodge of at least 2 and 4 position indentation for mappings and 2, 3 and 4 position indentation for sequence items.

That docker-compose hasn't complained about:

ports:
 - "80:80"
  - "443:443"

in your file yet is unexpected, as it is not valid YAML.

Answer 2

'lint'（语法检查）docker-compose.yml使用http://www.yamllint.com/ ，更正语法错误，然后重新运行Docker命令。