The last time I wrote about Ansible and the possibility to use blocks to group multiple tasks. Which you can read here. Sadly this feature does not work with loop, so there is no clean way to loop over multiple tasks in a play without writing the same loop statement at tasks over and over.
But when we come across the need of tasks which depend on each other, for example, we execute a script with a certain parameter and its result is necessary for the upcoming tasks.
Let’s go through a common example, creating a site consists of a few steps. Creating the directory, creating the vhost and then enabling the site.
- name: "create {{ site }} directory"
file:
ensure: directory
dest: "/var/www/{{ site }}"
- name: "create {{ site }}"
template:
src: vhost.j2
dest: "/etc/apache2/sites-available/{{ site }}"
register: vhost
- name: "enable {{ site }}"
command: /usr/sbin/a2ensite "{{ site }}"
register: result
when: vhost.changed
changed_when: "'Enabling site' in result.stdout"
notify: apache_reload
We could use a loop for each tasks and afterwards find the right result for the next task to depend on. But the styleguide will warn you if you try to use Jinja2 syntax in when statements.
So the best solution to this is to use include_tasks, which can include a file with tasks. This task is allowed to have a loop directive and so we can include it multiple times.
Lets see how this would apply to our scenario:
- set_fact:
sites:
- default
- icingaweb2
- name: create vhosts
include_tasks: create-vhosts.yml
loop: "{{ sites }}"
loop_control:
loop_var: site
In the Result we can see clearly that all tasks are applied for each element in the sites variable.
TASK [set_fact] *********************************************
ok: [localhost]
TASK [create vhosts] ****************************************
included: /Users/twening/Documents/netways/ansible_test20/create-vhosts.yml for localhost => (item=default)
included: /Users/twening/Documents/netways/ansible_test20/create-vhosts.yml for localhost => (item=icingaweb2)
TASK [create default directory] *****************************
ok: [localhost]
TASK [create default] ***************************************
ok: [localhost]
TASK [enable default] ***************************************
ok: [localhost]
TASK [create icingaweb2 directory] **************************
ok: [localhost]
TASK [create icingaweb2] ************************************
ok: [localhost]
TASK [enable icingaweb2] ************************************
ok: [localhost]
PLAY RECAP **************************************************
localhost : ok=10 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
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