如何移除Cisco配置输出尾随空格以通过Ansible断言验证

问题背景 #

需要用Ansible的assert模块验证Cisco设备的policy-maps配置，但设备返回的部分配置行存在尾随空格，导致断言匹配失败。尝试过trim、strip等过滤器但未生效，需找到正确的处理方式。

现有Playbook代码 #

- name: Get running class-map & policy-map config
  vars:
    ansible_connection: network_cli
  ios_command:
    commands:
      - 'show run | sec class-map|policy-map'
  register: show_policy

- name: Print trim
  debug:
    var: show_policy.stdout_lines | trim

- name: Ansible block with assert module
  block:
    - name: Validate running line
      ansible.builtin.assert:
        that:
          - "lookup('template', 'policy_desired.j2').splitlines() in show_policy.stdout_lines"
        success_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: PASSED"
        fail_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: FAILED"

输出示例 #

{
    "show_policy.stdout_lines | trim": [
        [
            "class-map match-any CM-QOS-GENERIC-BESTEFFORT-MARK",
            "  description Generic - Best Effort",
            " match access-group name ACL-QOS-GENERIC-BESTEFFORT",
            "class-map match-any CM-QOS-1P3Q-Q1",
            " match dscp cs4  cs5  ef ",        <--- 注意此处的尾随空格
            "class-map match-any CM-QOS-1P3Q-Q2",
            " match dscp cs6  cs7 ",
            "class-map match-any CM-QOS-1P3Q-Q3",
            " match dscp cs1 "
        ]
    ]
}   

已尝试的无效过滤器 #

- name: Print trim
  debug:
    var: show_policy.stdout_lines | trim

- name: Print trim
  debug:
    var: show_policy.stdout_lines | strip

- name: Print trim
  debug:
    var: show_policy.stdout_lines.strip()

- name: Print trim
  debug:
    var: "{{ show_policy.stdout_lines | map('trim') }}"

- name: Print trim
  debug:
    var: "{{ show_policy.stdout_lines | trim }}"

正确解决方案 #

问题根源 #

show_policy.stdout_lines是二维列表：外层列表对应每个执行的命令结果（此处仅一个命令），内层列表是具体的配置行。之前的过滤器未生效，是因为直接对整个二维列表操作，而非遍历内层列表的每一行字符串。

修改后的Playbook #

方法1：先预处理配置行（推荐）

- name: Get running class-map & policy-map config
  vars:
    ansible_connection: network_cli
  ios_command:
    commands:
      - 'show run | sec class-map|policy-map'
  register: show_policy

- name: 处理配置行，移除每行的首尾空格
  set_fact:
    processed_policy_lines: "{{ show_policy.stdout_lines[0] | map('trim') | list }}"

- name: Ansible block with assert module
  block:
    - name: Validate running line
      ansible.builtin.assert:
        that:
          - "lookup('template', 'policy_desired.j2').splitlines() in processed_policy_lines"
        success_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: PASSED"
        fail_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: FAILED"

方法2：直接在断言中处理

- name: Get running class-map & policy-map config
  vars:
    ansible_connection: network_cli
  ios_command:
    commands:
      - 'show run | sec class-map|policy-map'
  register: show_policy

- name: Ansible block with assert module
  block:
    - name: Validate running line
      ansible.builtin.assert:
        that:
          - "lookup('template', 'policy_desired.j2').splitlines() in (show_policy.stdout_lines[0] | map('trim') | list)"
        success_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: PASSED"
        fail_msg: "TEST: {{ UNIT_HOSTNAME }}: VALIDATE RUNNING POLICY: FAILED"

说明 #

• show_policy.stdout_lines[0]：取第一个命令的输出列表（因为只执行了一个show命令）
• map('trim')：遍历列表中的每一行，执行trim操作（移除首尾空格，包括尾随空格）
• | list：将map返回的迭代器转换为列表，方便后续断言匹配

内容的提问来源于stack exchange，提问作者C.AN5