Ansible condition always evaluates to false

问题

I'm trying to examine the output of a shell command for a particular string which indicates an error, and that the playbook should be terminated.

I'm trying to debug it something like this:

- debug: var=foo_result

- debug: msg={{ 'Some error text' in foo_result }}

In this example, install_result was registered to contain the output of the command, and it does:

TASK: [do_stuff | debug var=foo_result] **************************** 
ok: [some-node] => {
    "foo_result": {
        "changed": true, 
        "msg": "All items completed", 
        "results": [
            {
                "changed": true, 
[Snip..]
                "stderr": "", 
                "stdout": "...Some error text..."
            }
        ]
    }
}

The second debug statement, which checked for "some error text" in foo_result always evaluates to "false".

I'm still finding the Ansible syntax a little confusing, I'm not sure what I did wrong here.

Ansible version: 1.6.10

回答1:

You almost have it. You want to be testing for the output in foo_result.results.stdout, not just in foo_result. From this example:

  - debug: var=foo_result

  - debug: msg={{ 'Some error text' in foo_result }}

  - debug: msg={{ 'Some error text' in foo_result.results.stdout }}

We get the following output (I'm running version 1.7.2):

TASK: [debug var=foo_result] **************************************************
ok: [localhost] => {
    "foo_result": {
        "changed": "true",
        "msg": "all items completed",
        "results": {
            "changed": "true",
            "stderr": "",
            "stdout": ".... Some error text ..."
        }
    }
}

TASK: [debug msg=False] *******************************************************
ok: [localhost] => {
    "msg": "False"
}

TASK: [debug msg=True] ********************************************************
ok: [localhost] => {
    "msg": "True"
}

回答2:

Ansible is weird. Maybe I'm just not "getting" it...

Notice in the original output, that foo_install.results contains an array with a single element. If you want to debug or test stdout for text, you can do it this way:

- debug: msg={{ 'My Error' in foo_result.results[0].stdout }}
  when: foo_result.changed

Notice I had to add array index notation to get this to print "true" properly.

But if I do this:

- name: Do Foo Stuff
  shell: /some/path/to/some/command
  register: foo_result
  failed_when: "'My Error' in foo_result.stdout"

I don't need to refer to results[0]. I don't know what's up with that difference. I don't know why accessing foo_result seems to work differently if I access it from the same task that registered it vs. a different task.

Maybe this is fixed in more recent versions, but this is what I needed to do to get this working in 1.6.10

来源：https://stackoverflow.com/questions/28882891/ansible-condition-always-evaluates-to-false

标签

ansible

ansible-playbook