Ansible-使用 if elif else 根据条件定义变量

Question

我有以下多个角色：haproxy，java，nginx，tomcat

├── ansible-test-host.yml
├── hapoxy
├── java
├── myplaybook.yml
├── nginx
└── tomcat

基本剧本是：myplaybook.yml如下所示：

---
- hosts: test-local
  connection: local
  vars:
    java_version: "1.8.0"

  roles:
    - java

因此，我的要求取决于指定的角色 java/tomcat/nginx 等，我有一个要填充的模板文件。假设我的逻辑如下：

if 
    role == java then in  template.j2  I have to set `JAVA_TOOL_OPTIONS= -Xmx10g -Xms5g` 
elif 
    role == tomcat then in  template.j2  I have to set `JAVA_OPTS= -Xmx10g -Xms5g` 
else    
    NOTHING 
endif

我还有其他潜在场景需要整理，但如果我得到了休息的基础，我就可以做到。

我在 java role main.yml 中尝试过的是这里

---
# tasks file for java
- name: output the 'ansible_' magic variables
  debug:
    msg: [
      "ansible_role_names = {{ ansible_role_names | default({}) }}",
      "ansible_dependent_role_names =  {{ ansible_dependent_role_names }}",
      "ansible_play_role_names = {{ ansible_play_role_names | default([]) | join(',') }}"
    ]

- name: set facts
  set_fact:
     DEFAULT_VAR: >
                {% if "{{ ansible_play_role_names | default([]) | join(',') }}" == "java" %}
                JAVA_TOOL_OPTIONS
                {% elif "{{ ansible_play_role_names | default([]) | join(',') }}" == 'tomcat' %}
                CATALINA_OPTS
                {% else %}
                NOTHING
                {% endif %}

- name: output my custom var- try1
  debug:
    msg: >
        {% if "{{ ansible_play_role_names | default([]) | join(',') }}" == "java" %}
        JAVA_TOOL_OPTIONS
        {% else %}
        NOTHING
        {% endif %}


- name: output my custom var - echo 
  debug:
    msg: "{{ DEFAULT_VAR }}"

我的输出如下

TASK [java : output the 'ansible_' magic variables] ****************************************************
ok: [127.0.0.1] => {
    "msg": [
        "ansible_role_names = ['java']",
        "ansible_dependent_role_names =  []",
        "ansible_play_role_names = java"
    ]
}

TASK [java : set facts] ********************************************************************************
ok: [127.0.0.1]

TASK [java : output my custom var- try1] ***************************************************************
ok: [127.0.0.1] => {
    "msg": " NOTHING \n"
}

TASK [java : output my custom var - echo] **************************************************************
ok: [127.0.0.1] => {
    "msg": " NOTHING \n"
}

PLAY RECAP *********************************************************************************************
127.0.0.1                  : ok=5    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

请帮助提供指示以实现此目的。