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Ansible – Concatenate list of items for command module without surrounding quotes

November 23, 2023

I’m trying to concatentate an Ansible list into a space seperate string without surrounding quotes within a shell or command module call.

The command I’m trying to use requires a space separated list of variables only.

So with the list:

somelist:
    - item1
    - item2

We can build the shell module task:

- name: Execute a command
  ansible.builtin.shell: >
    /some/command {{ somelist | split(' ') }}

Which translates on the actual command to:

/some/command 'item1 item2'

However, the command in question requires a space separated list of variables, not a string – such as:

/some/command item1 item2

I could use loop but that produces a list of dictionaries in the captured results which I then can’t use as a conditional for the when: clause on the task.

Is there some way to convert the Ansible list to the above format?

>Solution :

We can build the shell module task:
- name: Execute a command
  ansible.builtin.shell: >
    /some/command {{ somelist | split(' ') }}
Which translates on the actual command to:
/some/command 'item1 item2'

Actually no. A simple test would just fail with

TASK [Execute a command] ******************************************************************
fatal: [localhost]: FAILED! =>
  msg: |-
    Unexpected templating type error occurred on (/some/command {{ somelist | split(' ') }}
    ): descriptor 'split' requires a 'unicode' object but received a 'list'

In order to concatenate a list of items one will need to join them.

A minimal example playbook

---
- hosts: localhost
  become: false
  gather_facts: false

  vars:

    somelist:
      - item1
      - item2

  tasks:

  - shell:
      cmd: "echo {{ somelist | join(' ') }}"
    register: result

  - debug:
      var: result

will result into an output of

TASK [debug] *************************
ok: [localhost] =>
  result:
    changed: true
    cmd: echo item1 item2
    delta: '0:00:00.013335'
    end: '2023-11-23 12:30:00.013334'
    failed: false
    msg: ''
    rc: 0
    start: '2023-11-23 12:30:00.000000'
    stderr: ''
    stderr_lines: []
    stdout: item1 item2
    stdout_lines:
    - item1 item2

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