如何将嵌套字典保存为jinja2 ansible中的变量？

Question

我正试图为我们的ansible角色创建一个prometheus.yml.j2模板。这是一个变量：

SCRAPE_CONFIGS:
  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

  - job_name: 'postgresql'
    static_configs:
      - targets: ['postgresql-exporter:9187']

我试过：

scrape_config:
  {% for scrape in SCRAPE_CONFIGS -%}
    {{ scrape }}
  {% endfor %}

这是输出：

scrape_config:
  {'job_name': 'prometheus', 'static_configs': [{'targets': ['localhost:9090']}]}
  {'job_name': 'postgresql', 'static_configs': [{'targets': ['postgresql-exporter:9187']}]}

但是它应该看起来像变量本身：

  scrape_config:
    - job_name: 'prometheus'
      static_configs:
        - targets: ['localhost:9090']

    - job_name: 'postgresql'
      static_configs:
        - targets: ['postgresql-exporter:9187']

否则，prometheus容器将引发语法错误，因为它无法正确读取prometheus.yml配置文件。有没有人有更好的建议来迭代这个嵌套的二叉树呢？结构应保持不变。还应该可以使用更多的条目添加不同的scrape_configs，如：

- job_name: 'elasticsearch'
  scrape_intervall: 10s
  scrape_timeout: 5s
  static_configs:
    - targets: ['elasticsearch-exporter:9114']

Answer 1

为什么不直接使用set_fact来重新创建所请求的字典结构，然后使用过滤器to_yaml将整个过程转储为YAML

考虑到剧本：

- hosts: all
  gather_facts: no

  tasks:
    - set_fact:
        config: 
          scrape_config: "{{ SCRAPE_CONFIGS }}"
      vars:
        SCRAPE_CONFIGS:
          - job_name: 'prometheus'
            static_configs:
              - targets: ['localhost:9090']

          - job_name: 'postgresql'
            static_configs:
              - targets: ['postgresql-exporter:9187']

    - copy:
        content: "{{ config | to_yaml }}"
        dest: prometheus.yml.j2

这将创建一个包含以下内容的文件prometheus.yml.j2：

scrape_config:
- job_name: prometheus
  static_configs:
  - targets: ['localhost:9090']
- job_name: postgresql
  static_configs:
  - targets: ['postgresql-exporter:9187']

为了增加一个额外的元素，

- hosts: all
  gather_facts: no

  tasks:
    - set_fact:
        config: 
          scrape_config: "{{ SCRAPE_CONFIGS + elements_to_add }}"
      vars:
        SCRAPE_CONFIGS:
          - job_name: 'prometheus'
            static_configs:
              - targets: ['localhost:9090']

          - job_name: 'postgresql'
            static_configs:
              - targets: ['postgresql-exporter:9187']

        elements_to_add:
          - job_name: 'elasticsearch'
            scrape_intervall: 10s
            scrape_timeout: 5s
            static_configs:
              - targets: ['elasticsearch-exporter:9114']

    - copy:
        content: "{{ config | to_yaml }}"
        dest: prometheus.yml.j2

将创建一个包含以下内容的文件prometheus.yml.j2：

scrape_config:
- job_name: prometheus
  static_configs:
  - targets: ['localhost:9090']
- job_name: postgresql
  static_configs:
  - targets: ['postgresql-exporter:9187']
- job_name: elasticsearch
  scrape_intervall: 10s
  scrape_timeout: 5s
  static_configs:
  - targets: ['elasticsearch-exporter:9114']