Compose: docker-compose 1.5.1 "contains an invalid type, it should be an array"

[opyate]

Test:

# in terminal 1, run a service like a database
docker run --rm --name first postgres

# in terminal 2
cat <<EOF > docker-compose.yml
second:
  image: busybox
  external_links:
   - first:uno
EOF
docker-compose run --rm second /bin/sh

Which will give you a BusyBox shell, and env shows the UNO_* env vars.

However, change the YAML to the following VALID YAML (e.g. try this linter or this one), and it will not work with docker-compose 1.5.1 (via DockerToolbox-1.9.1a.pkg).

second:
  image: busybox
  external_links: {first: uno}

[dnephin]

It is valid yaml, but it is not a valid Compose file. {} is an object, not an array. You need:

second:
  image: busybox
  external_links: ['first:uno']

[opyate]

Obvious in retrospect, thanks!

[opyate]

@bfirsh just checking if a PR introducing this feature is a good idea or not: for keys that require an array (like external_links), also get them to support an object.

This makes the YAML file clearer if one mostly has arrays of one item.

Before:

foo:
  image: busybox
  environment:
   - "PORT:9000"
  external_links:
   - "bar:quux"

After:

foo:
  image: busybox
  environment: "PORT:9000"
  external_links: "bar:quux"

[habin-prasad]

It Worked for me when I updated the indentation and placed it inside an array.

[sreekanthdev]

ERROR:The Compose file './docker-compose.yml' is invalid because:
Unsupported config option for services.mydb: 'MYSQL_ROOT_PASSWORD'
services.mydb.environment contains an invalid type, it should be an object, or an array

[OneCricketeer]

Unsupported config option for services.mydb: 'MYSQL_ROOT_PASSWORD

You are completely missing environment @sreekanthdev

[Obinna5]

@OneCricketeer What does that even mean? I'm having the same problem but I don't understand your solution.

[OneCricketeer]

@Obinna5

services:
  mydb:
    image: mysql 
    environment:  # this is an array 
      - MYSQL_ROOT_PASSWORD='password123'

I suggest you study what objects (or hashes) and arrays (or lists) mean in YAML