Ansible only run when subelement of variable exists - ansible

Question

I have some variables defined like this:
x_php_versions_installed:
php70:
- php70-curl
- php70-xml
- php70-xmlrpc
- php70-zip
- pecl-memcached
php71:
- php71-curl
- php71-xml
- php71-xmlrpc
- php71-zip
php72:
- php72-curl
- php72-xml
- php72-xmlrpc
- php72-zip
- pecl-memcached
And I would like to check all of the vars (php70, php71, php72 and so on) has this variable: pecl-memcached and if one has, then run a command. My playbook looks like this:
- name: memcached pecl install
pear:
executable: '/usr/local/{{ item }}/bin/pecl'
name: 'pecl/memcached'
state: 'latest'
with_items: '{{ x_php_versions_installed | list }}'
when: 'item.pecl-memcached is defined'
this should call the /usr/local/php70/bin/pecl and /usr/local/php72/bin/pecl binary to install memcached. As soon as I remove the when condition, it works very well, but it will call every variable inside x_php_versions_installed not only where pecl-memcached is defined. So I need to fix the when condition in this case, but all of my tries are gives me an error.

Answer 1

If you want your when to check a list properly, you'll have to use the test operator in of Jinja:
- name: memcached pecl install
pear:
executable: '/usr/local/{{ item }}/bin/pecl'
name: 'pecl/memcached'
state: 'latest'
with_items: '{{ x_php_versions_installed | list }}'
when: "'pecl-memcached' in x_php_versions_installed[item]"
Given the playbook:
- hosts: localhost
gather_facts: no
vars:
x_php_versions_installed:
php70:
- php70-curl
- php70-xml
- php70-xmlrpc
- php70-zip
- pecl-memcached
php71:
- php71-curl
- php71-xml
- php71-xmlrpc
- php71-zip
php72:
- php72-curl
- php72-xml
- php72-xmlrpc
- php72-zip
- pecl-memcached
tasks:
- debug:
msg: "{{ item }}"
with_items: "{{ x_php_versions_installed | list }}"
when: "'pecl-memcached' in x_php_versions_installed[item]"
The recap would be:
TASK [debug] *******************************************************************
ok: [localhost] => (item=php70) => {
"msg": "php70"
}
skipping: [localhost] => (item=php71)
ok: [localhost] => (item=php72) => {
"msg": "php72"
}
Your subelement is a list not a dictionary, so accessing an element key like your are trying here, i.e.:
when: "x_php_versions_installed[item]['pecl-memcached'] is defined"
would work on a dictionary like this one:
x_php_versions_installed:
php70:
php70-curl:
php70-xml:
php70-xmlrpc:
php70-zip:
pecl-memcached:
# same goes for the other versions of PHP
Given the playbook:
- hosts: localhost
gather_facts: no
vars:
x_php_versions_installed:
php70:
php70-curl:
php70-xml:
php70-xmlrpc:
php70-zip:
pecl-memcached:
php71:
php71-curl:
php71-xml:
php71-xmlrpc:
php71-zip:
php72:
php72-curl:
php72-xml:
php72-xmlrpc:
php72-zip:
pecl-memcached:
tasks:
- debug:
msg: "{{ item }}"
with_items: "{{ x_php_versions_installed | list }}"
when: "x_php_versions_installed[item]['pecl-memcached'] is defined"
The recap would be:
TASK [debug] *******************************************************************
ok: [localhost] => (item=php70) => {
"msg": "php70"
}
skipping: [localhost] => (item=php71)
ok: [localhost] => (item=php72) => {
"msg": "php72"
}