Ansible循环，直到条件匹配为止. [英] Ansible loop till the condition matches.

问题描述

我想进行一系列的API调用，在每次调用后检查结果中的特定参数，如果该参数大于特定值，则将其保存在寄存器中并继续执行剧本.

基本上，我正在对RHEV进行API调用以检查存储域.然后，我要检查存储域是否有足够的空间，如果可以，请将该存储域ID存储在寄存器中以在存储域上创建磁盘.

以下是我如何通过单个API调用storagedomain的代码段.

 - name: Get Free Storage Domain On RHEV
  uri:
    url: "{{ rhevurl }}/storagedomains/7649aea2-d87c-4066-acca-4399d5261ade"
    method: GET
    user: "{{ rhevusername }}"
    password: "{{ rhevpassword }}"
    return_content: yes
    headers:
      Version: 4
      Accept: "application/xml"
      Content-type: "application/xml"
  register: storagedomain
  tags: storagedomain


- name: Retriving size.
  xml:
    xmlstring: "{{ storagedomain.content }}"
    xpath: /storage_domain/available
    content: text
  register: availablesize
  tags: storagedomain


- name: storage_domain size
  debug:
    var: availablesize.matches[0].available
  tags: storagedomain

现在，我想对多个存储域执行此过程，并且当循环获得具有可用空间的storagedomain时，循环应该会中断.

如下所示.

- name: Get Free Storage Domain On RHEV
  uri:
    url: "{{ rhevurl }}/storagedomains/{{ item }}"
    method: GET
    user: "{{ rhevusername }}"
    password: "{{ rhevpassword }}"
    return_content: yes
    headers:
      Version: 4
      Accept: "application/xml"
      Content-type: "application/xml"
  loop:
    - 7649aea2-d87c-4066-acca-4399d5261ade
    - 40cceee7-a8d3-45af-a2d0-70c414be32cc
    - a81411b0-4ddb-4467-a4c6-ac9364905248
    - b288c547-231c-44b9-8329-98adcbdfc726 
    - 8cdef991-3edc-4c35-9228-feeef8f29004
    - 837a2e1b-6365-4309-a526-0cd05801fe43
    - 8981bf82-a1da-405e-a7f5-d84f2c94d71d
    - 7a9e3904-e37b-48fd-b850-0f026dc5cde9

在循环中，我应该如何使用xml模块解析xml，然后检查大于特定大小的可用空间的条件

解决方案

您不能中断循环，但是如果您的条件满足任何条件，则可以跳过循环执行.看看下面的例子.

test.yml 该剧本将执行shell模块，并忽略错误&设置var1变量.但是block模块将仅在未定义var1之前执行.

- block:
  - shell: expr {{item}} + 1
    ignore_errors: yes
    register: cmd_stat

  - set_fact: var1={{item}}
    when: cmd_stat.rc == 0
  when: var1 is not defined

sites.yml (根据您的循环项，此剧本多次包含test.yml剧本).

---
- hosts: localhost
  connection: local
  vars:
  tasks:
    - include: test.yml
      loop: ["abc","def", "ghi",1, "jkl"]

    - name: increase var1 variable by 1 and write to text file
      shell: expr {{var1}} + 1 > text

因此，使用与您可以在剧本中实现的逻辑相同的逻辑.例如url获得200状态，然后设置storage变量&与when条件一起使用.

我希望您能够理解该示例.

I want to make the series of API calls, after each call check for a particular parameter in the result, if it greater than particular value save it in register and continue further playbook execution.

Basically I am making an API call to RHEV to check the storage domain. Then I want to check if storage domain have the sufficient space, if yes, store that storage domain id in register to create the disk on the storage domain.

Below is the snippet how I do it for single API call to storagedomain.

 - name: Get Free Storage Domain On RHEV
  uri:
    url: "{{ rhevurl }}/storagedomains/7649aea2-d87c-4066-acca-4399d5261ade"
    method: GET
    user: "{{ rhevusername }}"
    password: "{{ rhevpassword }}"
    return_content: yes
    headers:
      Version: 4
      Accept: "application/xml"
      Content-type: "application/xml"
  register: storagedomain
  tags: storagedomain


- name: Retriving size.
  xml:
    xmlstring: "{{ storagedomain.content }}"
    xpath: /storage_domain/available
    content: text
  register: availablesize
  tags: storagedomain


- name: storage_domain size
  debug:
    var: availablesize.matches[0].available
  tags: storagedomain

Now I want to do this process for multiple storage domain, and loop should break when it gets storagedomain with available space.

Something like below.

- name: Get Free Storage Domain On RHEV
  uri:
    url: "{{ rhevurl }}/storagedomains/{{ item }}"
    method: GET
    user: "{{ rhevusername }}"
    password: "{{ rhevpassword }}"
    return_content: yes
    headers:
      Version: 4
      Accept: "application/xml"
      Content-type: "application/xml"
  loop:
    - 7649aea2-d87c-4066-acca-4399d5261ade
    - 40cceee7-a8d3-45af-a2d0-70c414be32cc
    - a81411b0-4ddb-4467-a4c6-ac9364905248
    - b288c547-231c-44b9-8329-98adcbdfc726 
    - 8cdef991-3edc-4c35-9228-feeef8f29004
    - 837a2e1b-6365-4309-a526-0cd05801fe43
    - 8981bf82-a1da-405e-a7f5-d84f2c94d71d
    - 7a9e3904-e37b-48fd-b850-0f026dc5cde9

In the loop how should I parse xml using xml module and then check for condition of available space greater the particular size

解决方案

You cannot break the loop, but can skip the loop execution if your condition satisfy at any item. check out the below example.

test.yml this playbook will execute shell module with ignore errors & set var1 variable. but the block module will only execute until var1 is not defined.

- block:
  - shell: expr {{item}} + 1
    ignore_errors: yes
    register: cmd_stat

  - set_fact: var1={{item}}
    when: cmd_stat.rc == 0
  when: var1 is not defined

sites.yml this play includes test.yml playbook multiple times based on your loops items.

---
- hosts: localhost
  connection: local
  vars:
  tasks:
    - include: test.yml
      loop: ["abc","def", "ghi",1, "jkl"]

    - name: increase var1 variable by 1 and write to text file
      shell: expr {{var1}} + 1 > text

So, using the same logic you can implement in your playbook. like if url get 200 status then set storage variable & use it with when condition.

I Hope you'll be able to understand the example.

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