当不同时，我如何将远程文件与控制器上的引用进行比较而不使剧本失败

Question

我有一个非常特殊的问题，在我的代码中，我必须将ansible值与客户期望值和客户期望的un_matched值进行比较，但是最终的剧本输出应该是failed =0而不是failed =1。

代码为：

- name: show file contents of customer-expects.txt
debug:
msg: "{{ lookup('file', '/customer-expects.txt') }}"
- shell: cat /etc/issue
register: issue
changed_when: false
ignore_errors: yes
- assert:
that:
- lookup('file', '/customer-expects.txt') == issue.stdout
success_msg: "matched! {{ lookup('file', '/customer-expects.txt') }} = {{ issue.stdout }}"
- name: show file contents customer-expects_unmatched.txt
debug:
msg: "{{ lookup('file', '/customer-expects_unmatched.txt') }}"
- shell: cat /etc/issue
register: issue
changed_when: false
ignore_errors: yes
- assert:
that:
- lookup('file', '/customer-expects_unmatched.txt') == issue.stdout
fail_msg: "unmatched! {{ lookup('file', '/customer-expects_unmatched.txt') }} = {{ issue.stdout }}"
success_msg: "matched! {{ lookup('file', '/customer-expects.txt') }} = {{ issue.stdout }}"

输出为：

[root@ansible-master /]# ansible-playbook tab8.role.yml -v
Using /etc/ansible/ansible.cfg as config file
PLAY [This output is for Tab-8 of Function Design document] *********
TASK [Gathering Facts] **********************************************
ok: [ansible-client1]
TASK [issue_tab8 : show file contents of customer-expects.txt] ******
ok: [ansible-client1] => {
"msg": ""
}
TASK [issue_tab8 : shell] *******************************************
ok: [ansible-client1] => {"changed": false, "cmd": "cat /etc/issue", "delta": "0:00:00.005200", "end": "2022-01-25 14:17:57.070688", "rc": 0, "start": "2022-01-25 14:17:57.065488", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
TASK [issue_tab8 : assert] ******************************************
ok: [ansible-client1] => {
"changed": false,
"msg": "matched!  = "
}
TASK [issue_tab8 : show file contents customer-expects_unmatched.txt] *
ok: [ansible-client1] => {
"msg": "abc"
}
TASK [issue_tab8 : shell] *******************************************
ok: [ansible-client1] => {"changed": false, "cmd": "cat /etc/issue", "delta": "0:00:00.004603", "end": "2022-01-25 14:17:57.674059", "rc": 0, "start": "2022-01-25 14:17:57.669456", "stderr": "", "stderr_lines": [], "stdout": "", "stdout_lines": []}
TASK [issue_tab8 : assert] ******************************************
fatal: [ansible-client1]: FAILED! => {
"assertion": "lookup('file', '/customer-expects_unmatched.txt') == issue.stdout",
"changed": false,
"evaluated_to": false,
"msg": "unmatched! abc = "
}
PLAY RECAP **********************************************************
ansible-client1            : ok=6    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

Answer 1

您采取了错误的方式，使其变得不必要的复杂IMO.

你必须明白，在ansible中制定一个剧本包括描述你想要找到目标机器的状态。在这种特殊情况下，您需要描述在目标上查找特定文件的状态。这基本上是通过使用copy模块的任务来完成的。一旦您完成了这项工作，了解文件是相似还是不同只是命令行切换或任务选项的问题。

有关以下解释的更多信息，请参阅验证任务

Ansible有一个check_mode，它可以让你运行整个剧本，只是为了验证它会做什么。你也可以无条件地将该模式应用于单个任务，使其始终作为检查运行(check_mode: true(，或者始终对远程目标进行更改(无论剧本的调用方式如何((check_mode: false(。我们对第一种形式感兴趣。

类似地，ansible有一个diff的可能性，它可以让你看到你描述的状态和它(应该(对目标应用的修改之间的区别。

上面的场景就是一个例子。我只针对我的本地机器进行了测试，但你可以在任何远程目标上获得完全相同的结果。

首先，让我们在ansible目录中创建要检查的引用文件。

mkdir -p files
echo "I'm the reference file" > files/ansible_reference.txt

对于这个例子，我现在将在我们的目标上创建一个相同和不同的文件，这样我们就可以比较这两种情况：

echo "I'm the reference file" > /tmp/ansible_similar.txt
echo "I'm a different file" > /tmp/ansible_different.txt

这是行动手册compare.yml

---
- name: compare remote file to a local reference
hosts: localhost
gather_facts: false
vars:
local_reference: ansible_reference.txt
remote_files_2_check:
- /tmp/ansible_similar.txt
- /tmp/ansible_different.txt
tasks:
- name: Dry run a copy with diff to check if remote file is aligned
copy:
src: "{{ local_reference }}"
dest: "{{ item }}"
check_mode: true
diff: true
loop: "{{ remote_files_2_check }}"

哪个给出：

$ ansible-playbook compare.yml
PLAY [compare remote file to a local reference] *****************************
TASK [Dry run a copy with diff to check if remote file is aligned] **********
ok: [localhost] => (item=/tmp/ansible_similar.txt)
--- before: /tmp/ansible_different.txt
+++ after: /home/user/ansible_project/files/ansible_reference.txt
@@ -1 +1 @@
-I'm a different file
+I'm the reference file
changed: [localhost] => (item=/tmp/ansible_different.txt)
PLAY RECAP ******************************************************************
localhost                  : ok=1    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0  

注：

• 尽管Ansible为不同的文件报告changed，但这只是会发生的情况。由于我们正在为给定的任务进行试运行，以上内容不会改变您的目标。您可以多次运行它，只要您不更改引用或目标状态，它就会报告相同的结果
• 如果你对任务的默认报告不满意，你可以注册结果，探索其内容，并在后续任务中使用它来满足你的确切要求
• 注意，上面可能会报告目标文件的权限上的差异。您可能需要在复制模块中对此进行调整，以避免误报