Ansible dependency with user define condition

I want to add one role in my playbook dependencies, but based on condition.

- name: Get all install pyenv versions
  command: '{{ pyenv_root }}bin/pyenv versions'
  register: available_versions
  tags:
      - get_pyenv_versions
  environment:
      PYENV_ROOT: "{{ pyenv_root }}"

dependencies:
    - { role: pyenv, python_versions: ["{{ mypython_version }}"], when: "mypython_version not in available_versions.stdout" }

What I want to do is, I want to check, all available pyenv versions, if mypython_version is not available, then only I want to invoke pyenv role, otherwise I dont want to invoke that.

It gives me syntax error

ERROR! Syntax Error while loading YAML.


The error appears to have been in '/root/ansible_playbooks/roles/mydeployment/meta/main.yaml': line 9, column 1, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:


dependencies:
^ here

exception type: <class 'yaml.parser.ParserError'>
exception: while parsing a block collection
  in "<unicode string>", line 1, column 1
did not find expected '-' indicator
  in "<unicode string>", line 9, column 1

How can I define variable get_pyenv_versions and use in my dependencies as condition?

Solution

To properly define dependencies in a role you have to:

Define your /meta/main.yml dependency under your role:

dependencies:
  - role: pyenv
    when: mypython_version not in versions

You have to call your role from your play:

---
- name: Role Dependency
  hosts: localhost
  gather_facts: False

tasks:
  - name: Get all install pyenv versions
    command: '{{ pyenv_root }}bin/pyenv versions'
    register: available_versions
    environment:
      PYENV_ROOT: "{{ pyenv_root }}"

roles:
  - role: mydeployment
    pyenv_version : "{{ mypython_version }}"
    versions      : "{{ available_versions.stdout }}"

Another example in my sandbox:

---
- name: Role Dependency
  hosts: localhost
  gather_facts: False

  roles:
  - role: role2
    role1 : "Heyr"

Meta:

dependencies:
  - role: role1
    when: role1 == "Hey"

Results:

PLAY [Role Dependency] *******************************************************************************************************

TASK [role1 : Debug] *********************************************************************************************************
skipping: [localhost]

TASK [role2 : Debug] *********************************************************************************************************
ok: [localhost] => {
    "msg": "Hello2"
}

But when variable is fine:

---
- name: Role Dependency
  hosts: localhost
  gather_facts: False

  roles:
  - role: role2
    role1 : "Heyr"

Result:

TASK [role1 : Debug] *********************************************************************************************************
ok: [localhost] => {
    "msg": "Hello1"
}

TASK [role2 : Debug] *********************************************************************************************************
ok: [localhost] => {
    "msg": "Hello2"
}

Hope it helps