在ansible中，如何在文件末尾添加一个文本块，并在标记之前添加一个空行？

Question

我有一个剧本，如下所示：

- hosts: localhost
  tasks:
    - name: update a file
      blockinfile:
        dest: /tmp/test
        block: |
          line 1
          line 2

运行剧本后，文件/tmp/test变为：

a # this is the end line of the original file
# BEGIN ANSIBLE MANAGED BLOCK
line 1
line 2
# END ANSIBLE MANAGED BLOCK

我想在标记“ # BEGIN ANSIBLE MANAGED BLOCK”之前添加一个空行（换行符）以获得视觉效果，最简单的方法是什么？最好在任务范围内，但欢迎任何想法。如果我重新定义标记，它将影响“BEGIN”和“END”标记。

Answer 1

如果您有一个如下所示的文件：

some line
foobar
some other line

并且您想在本示例中的模式“foobar”之前添加换行符，以下 ansible 代码将为您完成此操作：

- hosts: localhost
  gather_facts: no
  connection: local
  tasks:
    - name: update a file
      replace:
        dest: /tmp/foobar
        regexp: |
          (?mx)     # "m" lets ^ and $ match next to imbedded \n, x allows white space for readability
          (?<!\n\n) # a Zero-Length Assertion that it does not have an empty line already
          ^         # beginning of the line
          (foobar)  # match "foobar" and save it as \1, it could be "\#\ BEGIN\ ANSIBLE\ MANAGED\ BLOCK" if that is your pattern
          $         # end of line
        replace: "\n\\1" # add a newline before the matched pattern

并且它是幂等的，当模式不存在时，它不会在文件末尾添加换行符。