如何用Ansible无额外字符打印文件内容？类似Linux的cat命令

问题场景 #

需要在Ansible Playbook中像Linux cat命令一样无额外字符地打印文件内容。现有文件/tmp/report-2023-10-19.html.txt内容如下：

server1 : The D:\ drive size is WRONG! Expected drive size: '1009'. Current size is: 100
server2 : The D:\ drive size is WRONG! Expected drive size: '1009'. Current size is: 100
server3 : The C:\ drive size is WRONG! Expected drive size: '12899'. Current size is: 126.51
server4 : The C:\ drive size is WRONG! Expected drive size: '12899'. Current size is: 126.51

原尝试的任务使用debug模块结合splitlines()，输出带有引号、逗号等多余字符：

- name: Display all findings
  debug:
   var: "file_content"
  vars:
   file_content: "{{ lookup('file', '/tmp/{{ reportfile }}.txt').splitlines() }}"
  delegate_to: localhost
  run_once: true
  when: num_lines.stdout | int > 0
  tags: always

输出结果包含冗余格式：

ok: [vmstfsh1 -> localhost] => {
    "file_content": [
        " server1 : The D:\\ drive size is WRONG! Expected drive size: '1009'. Current size is: 100 ",
        "",
        " server2 : The D:\\ drive size is WRONG! Expected drive size: '1009'. Current size is: 100 ",
        "",
        " server3 : The C:\\ drive size is WRONG! Expected drive size: '12899'. Current size is: 126.51 ",
        "",
        " server4 : The C:\\ drive size is WRONG! Expected drive size: '12899'. Current size is: 126.51"
    ]
}

解决方案 #

方法1：直接输出文件原始内容 #

使用debug模块的msg参数，直接输出lookup获取的文件原始内容，不进行splitlines()处理，Ansible会自动解析换行符：

- name: Display file content like cat
  debug:
    msg: "{{ lookup('file', '/tmp/' ~ reportfile ~ '.txt') }}"
  delegate_to: localhost
  run_once: true
  when: num_lines.stdout | int > 0
  tags: always

注意：变量拼接使用~而非嵌套双大括号，避免语法问题。

方法2：直接执行cat命令 #

通过command模块在目标主机（此处为localhost）执行cat命令，注册输出后打印：

- name: Execute cat command
  command: cat "/tmp/{{ reportfile }}.txt"
  register: cat_result
  delegate_to: localhost
  run_once: true
  when: num_lines.stdout | int > 0
  tags: always
  changed_when: false  # 标记任务为未变更，避免影响playbook状态

- name: Print cat output
  debug:
    msg: "{{ cat_result.stdout }}"
  delegate_to: localhost
  run_once: true
  when: num_lines.stdout | int > 0
  tags: always

方法3：使用stdout_callback简化输出（可选） #

如果希望全局简化输出格式，可以临时设置ANSIBLE_STDOUT_CALLBACK=debug环境变量运行playbook，配合方法1或2使用，能进一步减少冗余的任务状态前缀：

ANSIBLE_STDOUT_CALLBACK=debug ansible-playbook your_playbook.yml

内容的提问来源于stack exchange，提问作者jeszi