Get sorted list of folders with Ansible

问题:

I have OS X "El capitan" 10.11.6 and I am using Ansible 2.1.1.0 to run some maintenance tasks on a remote Linux server Ubuntu 16.04 Xenial. I am trying to get the following list of folders sorted, so I can remove the old ones when needed:

/releases/0.0.0
/releases/0.0.1
/releases/0.0.10
/releases/1.0.0
/releases/1.0.5
/releases/2.0.0

I have been trying with the module find in Ansible, but it returns a not sorted list. Is there an easy way to achieve this with Ansible?

回答1:

You can sort items with sort filter:

- hosts: localhost
  gather_facts: no
  tasks:
    - find: path="/tmp" patterns="test*"
      register: files

    - debug: msg="{{ files.files | sort(attribute='ctime') | map(attribute='path') | list }}"

Just change sort attribute to your need.
But beware that string sort is not numeric, so /releases/1.0.5 will go after /releases/1.0.10.

回答2:

Interesting solutions, thanks a lot guys. But I think I have found the easiest way in Ubuntu, just using ls -v /releases/ will apply natural sorting to all folders:

- name: List of releases in ascendent order  
  command: ls -v /releases/
  register: releases

- debug: msg={{ releases.stdout_lines }}

The response is:

ok: [my.remote.com] => {
    "msg": [
        "0.0.0",
        "0.0.1",
        "0.0.10",
        "1.0.0",
        "1.0.5",
        "2.0.0"
    ]
}

回答3:

If you want to find files older than a period, maybe age and age_stamp parameters of find module can help you. For example:

# Recursively find /tmp files older than 4 weeks and equal or greater than 1 megabyte
- find: paths="/tmp" age="4w" size="1m" recurse=yes

回答4:

It sounds like what you want to do is real simple but the standard ansible modules doesn't quite have what you needed.

As an alternative you can write your own script using your favorite programming language then use the copy module to pass that script to the host and use command to execute it. When done, use file to remove that script.

The downside of it is that the target host will need to have the required executable to run your script. For instance if you are doing a python script then the target host will need python

Example:

- name: Send your script to the target host
  copy: src=directory_for_scripts/my_script.sh dest=/tmp/my_script.sh
- name: Execute my script on target host
  command: >
          /bin/bash /tmp/my_script.sh
- name: Clean up the target host by removing script
  file: path=/tmp/my_script.sh state=absent