如果文件有模式，如何跳过Ansible中的模板副本

Question

如果目标文件中没有字符串，则尝试仅复制Nginx配置文件。

我以为这会奏效：

- name: Copy nginx config file
template:
src: templates/nginx.conf
dest: /etc/nginx/sites-enabled/default
validate: grep -l 'managed by Certbot' %s

但是如果"；由Certbot管理"；不在文件中，并停止运行剧本。

如果目标文件已经具有该模式，我如何跳过模板副本？也许有更好的方法可以得到同样的结果？

Answer 1

灵感来自其他答案

您可以在检查模式下使用lineinfile模块检查文件中是否存在内容。然后，您可以将结果用作模板任务的条件。条件中的default是为了应对文件不存在并且found属性不在注册结果中的情况。

---
- name: Check for presence of "managed by Certbot" in file
lineinfile:
path: /etc/nginx/sites-enabled/default
regexp: ".*# managed by Certbot.*"
state: absent
check_mode: yes
changed_when: false
register: certbot_managed
- name: Copy nginx config file when not certbot managed
template:
src: templates/nginx.conf
dest: /etc/nginx/sites-enabled/default
when: certbot_managed.found | default(0) == 0

Answer 2

您可以使用failed_when条件，并将其建立在validate生成的失败消息(failed to validate(的基础上：

- name: Copy nginx config file
template:
src: templates/nginx.conf
dest: /etc/nginx/sites-enabled/default
validate: grep -l 'managed by Certbot' %s
failed_when: 
- copy_config_file.failed
- copy_config_file.msg != 'failed to validate'
register: copy_config_file

^{注意：在when和*_when中，有一个条件列表就像执行list.0 and list.1 and ...}

---

给定剧本：

- hosts: all
gather_facts: no
tasks:
- copy:
dest: templates/nginx.conf
content: "{{ content | default('some random content') }}"
- copy:
dest: /etc/nginx/sites-enabled/default
content: "blank"
- template:
src: templates/nginx.conf
dest: /etc/nginx/sites-enabled/default
validate: grep -l 'managed by Certbot' %s
failed_when: 
- copy_config_file.failed
- copy_config_file.msg != 'failed to validate'
register: copy_config_file
- shell: cat templates/nginx.conf
register: template_content
failed_when: false
- shell: cat /etc/nginx/sites-enabled/default
register: file_content
failed_when: false
- debug:
var: template_content.stdout

- debug:
var: file_content.stdout

1. 通过以下方式运行时：

   ansible-playbook play.yml
   

   它提供：

   PLAY [all] *******************************************************************************************************
   TASK [copy] ******************************************************************************************************
   changed: [localhost]
   TASK [copy] ******************************************************************************************************
   changed: [localhost]
   TASK [template] **************************************************************************************************
   ok: [localhost]
   TASK [shell] *****************************************************************************************************
   changed: [localhost]
   TASK [shell] *****************************************************************************************************
   changed: [localhost]
   TASK [debug] *****************************************************************************************************
   ok: [localhost] => {
   "template_content.stdout": "some random content"
   }
   TASK [debug] *****************************************************************************************************
   ok: [localhost] => {
   "file_content.stdout": "blank"
   }
   PLAY RECAP *******************************************************************************************************
   localhost                  : ok=7    changed=4    unreachable=0    failed=0     skipped=0    rescued=0    ignored=0   
   

2. 现在，当与一起跑步时

   ansible-playbook play.yml -e "content='managed by Certbotnsome other content'"
   

   通过一个额外的参数来修改模板的内容，它给出：

   PLAY [all] *******************************************************************************************************
   TASK [copy] ******************************************************************************************************
   ok: [localhost]
   TASK [copy] ******************************************************************************************************
   changed: [localhost]
   TASK [template] **************************************************************************************************
   changed: [localhost]
   TASK [shell] *****************************************************************************************************
   changed: [localhost]
   TASK [shell] *****************************************************************************************************
   changed: [localhost]
   TASK [debug] *****************************************************************************************************
   ok: [localhost] => {
   "template_content.stdout": "managed by Certbotnsome other content"
   }
   TASK [debug] *****************************************************************************************************
   ok: [localhost] => {
   "file_content.stdout": "managed by Certbotnsome other content"
   }
   PLAY RECAP *******************************************************************************************************
   localhost                  : ok=7    changed=4    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0