Question 172159 in Ubuntu Question posted in
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Can Ubuntu replace a string with a custom environment value?

I need to replace a specific string inside a file with the value of an environment variable, but I only get and empty value.

Here my code:

- template:
    src: myfile.yml
    dest: /etc/myfile.yml
    mode: '0755'

- name: Update template env
  become: true
  shell: sed -i "s/HELK_ID/{{ lookup('env', 'HELK_ID') }}/" /etc/myfile.yml

Inside /etc/environment:

HELK_ID=aaaa

How can I replace the string with the environment value?

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2

Answers


  1. 0

    I only get and empty value.

    Since Lookup plugins

    Like all templating … execute and are evaluated on the Ansible Control Machine …

    the env lookup – Read the value of environment variables

    Allows you to query the environment variables available on the Controller when you invoked Ansible.

    To gather the environment on the Remote Node it is recommended to gather_facts about the env. The answer under Is it possible to gather only specific facts in Ansible? show also how to debug.

    After that tasks like

    - name: Update template env
  become: true
  shell: "sed -i 's/HELK_ID/{{ ansible_facts.env.HELK_ID }}/' /etc/myfile.yml"

    are possible.

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  2. 0

    You can’t expect the module shell will provide you by default with the environment variables from /etc/environment. The file /etc/environment is used by PAM. If you need it, it’s easier to read and parse the file on your own. For example, given the file

    shell> cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
HELK_ID=aaaa

    read the file

        - command: cat /etc/environment
      register: env_out

    and use the filter community.general.jc

      env: "{{ env_out.stdout|community.general.jc('ini') }}"

    gives

      env:
    HELK_ID: aaaa
    PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

    Given the file

    shell> cat /tmp/myfile.yml 
var1: [foo, HELK_ID, bar]

    Use the module replace to substitute the environment variable

        - replace:
        path: /tmp/myfile.yml
        regexp: 'HELK_ID'
        replace: "{{ env.HELK_ID }}"

    gives, running with ‘–check –diff’ options

    TASK [replace] *******************************************************************************
--- before: /tmp/myfile.yml
+++ after: /tmp/myfile.yml
@@ -1 +1 @@
-var1: [foo, HELK_ID, bar]
+var1: [foo, aaaa, bar]

    Example of a complete playbook for testing

    - hosts: all

  vars:

    env: "{{ env_out.stdout|community.general.jc('ini') }}"
    
  tasks:

    - command: cat /etc/environment
      register: env_out
      check_mode: false  # runs the command also with --check
    - debug:
        var: env
    - replace:
        path: /tmp/myfile.yml
        regexp: 'HELK_ID'
        replace: "{{ env.HELK_ID }}"

    gives

    shell> ansible-playbook pb.yml -l localhost --check --diff

PLAY [all] ***********************************************************************************

TASK [command] *******************************************************************************
changed: [localhost]

TASK [debug] *********************************************************************************
ok: [localhost] => 
  env:
    HELK_ID: aaaa
    PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

TASK [replace] *******************************************************************************
--- before: /tmp/myfile.yml
+++ after: /tmp/myfile.yml
@@ -1 +1 @@
-var1: [foo, HELK_ID, bar]
+var1: [foo, aaaa, bar]

changed: [localhost]

PLAY RECAP ***********************************************************************************
localhost: ok=3    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

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