when condition to evaluate list of values inside with_items - ansible

Question

My intention with below playbook is to run a shell command only when it finds any of the value from disk_list. I need help to frame out when condition as told above.
---
- hosts: localhost
connection: local
gather_facts: false
tasks:
- set_fact:
disk_list:
- sda
- sdb
- sdc
- name: Get df -hT output to know XFS file system
shell: df -hT |grep xfs|awk '{print $1}'
register: df_result
- name: Run shell command on each XFS file system
shell: ls -l {{ item }} | awk '{print $1}'
with_items: "{{ df_result.stdout_lines }}"
when: "{{ disk_list.[] }} in {{ item }}"
BTW, in my system, "df_result" variable looks as below:
TASK [debug] ***************************************************************************************************************************************
ok: [localhost] => {
"df_result": {
"changed": true,
"cmd": "df -hT |grep xfs|awk '{print $1}'",
"delta": "0:00:00.017588",
"end": "2019-03-01 23:55:21.318871",
"failed": false,
"rc": 0,
"start": "2019-03-01 23:55:21.301283",
"stderr": "",
"stderr_lines": [],
"stdout": "/dev/sda3\n/dev/sda1",
"stdout_lines": [
"/dev/sda3",
"/dev/sda1"
]
}
}
Please help !

Answer 1

Some notes on the playbook.
For localhost, connection: local is implicit. So there is no technical need to specify this.
set_fact is correct, but in this case I believe is more appropiate to use "vars" at a play level instead of the set_fact module in a task. This also allows you to use "vars_files" for easier use of disk device lists.
I would reccomend to try to keep your task names "easy", as you may want to use the --start-at-task option at some point.
with_items is depricated in favor of "loop".
The conditional "when" works at a task level. So it will execute the task (for all its items) if the condition is met.
Here is a working version of what you need which also reflects the (5) recommendations made:
---
- hosts: localhost
gather_facts: false
vars:
disk_list:
- sda
- sdb
- sdc
tasks:
- name: cleans previous runs
shell: cat /dev/null > /tmp/df_result
- name: creates temporary file
shell: df -hT | grep ext4 | grep -i {{ item }} | awk '{print $1}' >> /tmp/df_result
loop: "{{ disk_list }}"
- name: creates variable
shell: cat /tmp/df_result
register: df_result
- name: shows info
shell: ls -l {{ item }} | awk '{print $1}'
loop: "{{ df_result.stdout_lines }}"
I basically just use a temporary file (/tmp/df_result) with the results you need already filtered by the "grep -i {{ item }}" used in the loop on task "creates temporary file". Then, the loop in "shows info" just iterates over an already clean list of items.
To see the result on screen, you could use "-v" option when running the playbook or if you want to save the result in a file, you could add " >> /tmp/df_final" at the end of the shell line in "shows info" task.
I accidently step on this post, which is kind of old. I'm sure you already fixed this in your environment, maybe you find a better way to do it, hopefully you did.
Regards,