Passing condition to "failed_when" as a variable

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1

I try to pass a condition to failed_when as a variable in a role:

my-role/defaults/main.yml:

# list of commands to execute in form [command, changed_when, failed_when]

my_commands:
  - ["myapp init", "cmd_result.rc == 0", "(cmd_result.rc != 0) and ('Non-critical error' not in cmd_result.stdout) and ('Non-critical error' not in cmd_result.stderr)"]
  - [...]

This would allow me to loop through the command list with custom changed_when and failed_when conditions:

my-role/tasks/main.yml:

- name: Execute commands
  ansible.builtin.include_tasks: my-task.yml
  loop: "{{ my_commands }}"
  loop_control:
    loop_var: my_command

my-role/tasks/my-task.yml:

- name: My task
 ansible.builtin.command: "{{ my_command[0] }}"
  register: cmd_result
  changed_when: my_command[1]
  failed_when: my_command[2]

But I face following behaviour:

  • task fails with non-zero return code :cross_mark:
  • if I copy the condition line into failed_when statement explicitly, like failed_when: "(cmd_result.rc != 0) and ('Non-critical error' not in cmd_result.stdout) and ('Non-critical error' not in cmd_result.stderr)", task works :white_check_mark:

I suppose it may be that

  • the statement is not evaluated properly
  • cmd_result variable is not injected into the conditional statement

Can anyone explain this, and maybe suggest an elegant and functional way to get this work?

Thank you!

Passing condition to "failed_when" as a variable
2

failed_when is evaluated to literal string ā€œ(cmd_result.rc != 0) and (ā€˜Non-critical errorā€™ not in cmd_result.stdout) and (ā€˜Non-critical errorā€™ not in cmd_result.stderr)ā€

What you want is to have same literal string ā€œ(cmd_result.rc != 0) and (ā€˜Non-critical errorā€™ not in cmd_result.stdout) and (ā€˜Non-critical errorā€™ not in cmd_result.stderr)ā€ to be used as condition.

In your case there is only one evaluation - my_command[2] is evaluated to string, ansible does just one evaluation.

The solution is


failed_when: "{{ my_command[2] }}"

In this case {{ my _command[2] }} is evaluated to as string (variable evaluation) and when string (condition you wrote) is evaluated as condition.

1 Like
3

Create the files on the fly. For example,

    - name: Create my commands.
      run_once: true
      delegate_to: localhost
      block:

        - name: Create directory for my commands.
          file:
            state: directory
            path: /tmp/my_commands

        - name: Create my commands.
          copy:
            dest: "{{ my_task }}"
            content: |
              ---
              - name: My task
                ansible.builtin.command: "{{ item.0 }}"
                register: cmd_result
                changed_when: "{{ item.1 }}"
                failed_when: "{{ item.2 }}"
          loop: "{{ my_commands }}"
          loop_control: 
            extended: true

Declare the filename as appropriate

my_task: "/tmp/my_commands/{{ ansible_loop.index }}-{{ item.0 }}.yml"

Then, execute the commands

    - name: Execute my commands.
      ansible.builtin.include_tasks: "{{ my_task }}"
      loop: "{{ my_commands }}"
      loop_control: 
        extended: true

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