best practices for removing files in a dir when using Ansible

[paneva]

Hi Ansible wizards!

I am currently working on few  tasks in a playbook that are going to remove old files. There is a set number of files that I need to keep, say 3 (most recent), and the rest should be removed. I am doing some math magic in Ansible and some shell commands to achieve this. I can't help but wonder, however, if this a "recommended" way of doing this kind of thing. It seems to me that I am doing too many tasks to achieve this and I begin to wonder if I am making this more complicated than it should be. Thanks in advance !!!

Here is what I have:

- name: Get list of txt all files in the directory - done for visibility

      shell:

         cmd: "ls -t *.txt"

         chdir: "{{a_dir}}"     

      register: list_all_files

  - name: Get total number of txt files in this dir

      shell:

          cmd: " ls -t *.txt | wc -l "

          chdir: "{{a_dir}}"     

      register: total_number_files     

     - set_fact: 

        number_of_files_to_keep: "3"

        curr_number_files: "{{total_number_files.stdout}}"    

        num_files_to_remove: "{{(total_number_files|int) - (number_of_files_to_keep |int)}}"  

     - name: Store the files to be removed in a list 

       shell:

          cmd: "ls -t | tail -{{num_files_toremove}}"   

       register: list_files_to_remove

[Stefan Hornburg (Racke)]

On 2/25/21 4:45 PM, paneva wrote:
> Hi Ansible wizards!
> I am currently working on few  tasks in a playbook that are going to remove old files. There is a set number of files
> that I need to keep, say 3 (most recent), and the rest should be removed. I am doing some math magic in Ansible and some
> shell commands to achieve this. I can't help but wonder, however, if this a "recommended" way of doing this kind of
> thing. It seems to me that I am doing too many tasks to achieve this and I begin to wonder if I am making this more
> complicated than it should be. Thanks in advance !!!
> Here is what I have:

> -name: Get list of txt all files in the directory - done for visibility

>       shell:
>          cmd: "ls -t *.txt"
>          chdir: "{{a_dir}}"     
>       register: list_all_files
>
>   - name: Get total number of txt files in this dir
>       shell:
>           cmd: " ls -t *.txt | wc -l "
>           chdir: "{{a_dir}}"     
>       register: total_number_files     
>
>      - set_fact: 
>         number_of_files_to_keep: "3"
>         curr_number_files: "{{total_number_files.stdout}}"    
>         num_files_to_remove: "{{(total_number_files|int) - (number_of_files_to_keep |int)}}"  
>
>     - name: Store the files to be removed in a list 
>        shell:
>           cmd: "ls -t | tail -{{num_files_toremove}}"   
>        register: list_files_to_remove

* Using shell module is bad practice (only needed in corner cases)
* List of files can be gathered by the find module

Regards
Racke

>
>
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--
Ecommerce and Linux consulting + Perl and web application programming.
Debian and Sympa administration. Provisioning with Ansible.

[Brian Coca]

Role i created for this purpose:
https://github.com/bcoca/ansible-tidy


--
----------
Brian Coca

[flowerysong]

Yeah, that's a big mess that avoids using most features that ansible provides. Even if you want to stick to the `ls` approach, there's no reason to call it so many times.

   - name: Get list of all txt files in the directory

      shell:
         cmd: ls -t *.txt
         chdir: "{{ a_dir }}"
      register: list_all_files

    - name: Store the files to be removed in a list

      set_fact:
        list_files_to_remove: "{{ list_all_files.stdout_lines[(number_of_files_to_keep | int):] }}"
      vars:
        number_of_files_to_keep: "3"

More idiomatic would be to use the `find` module:

    - name: Find existing text files
      find:
        path: "{{ a_dir }}"
        pattern: "*.txt"
      register: result

    - name: Remove all but 3 files
      file:
        dest: "{{ item.path }}"
        state: absent
      loop: "{{ (result.files | sort(attribute='mtime'))[:-3] }}"