Is it possible to set a fact of an array in Ansible?

Question

Is it possible to set a fact containing a list in Ansible using set_fact? What's the correct syntax for it?

Answer 1

Yes, this is possible. As mentioned in another answer, you can set an array using double quotes, like so:

- name: set foo fact to a list   set_fact:      foo: "[ 'one', 'two', 'three' ]" 

However, I thought I'd create another answer to indicate that it's also possible to add to an existing array, like so:

- name: add items to foo list fact   set_fact:      foo: "{{foo}} + [ 'four' ]" 

Combining these and adding debugging as a playbook (which I'm calling facts.yml) like so:

--- - name: test playbook   gather_facts: false   hosts: localhost   tasks:     - name: set foo fact to an array       set_fact:          foo: "[ 'one', 'two', 'three' ]"     - debug:          var: foo     - name: add items to foo array fact       set_fact:          foo: "{{foo}} + [ 'four' ]"     - debug:          var: foo 

Produces (via ansible-playbook facts.yml) the following:

PLAY [test playbook] ********************************************************   TASK: [set foo fact to an array] ******************************************** ok: [localhost]  TASK: [debug var=foo] ******************************************************* ok: [localhost] => {     "foo": [         "one",          "two",          "three"     ] }  TASK: [add items to foo array fact] ***************************************** ok: [localhost]  TASK: [debug var=foo] ******************************************************* ok: [localhost] => {     "foo": [         "one",          "two",          "three",          "four"     ] }  PLAY RECAP ******************************************************************  localhost                  : ok=4    changed=0    unreachable=0    failed=0    

Answer 2

Indeed it is. You need to quote the entire list though:

- name: set fact   set_fact: foo="[ 'one', 'two', 'three' ]"  - name: debug   debug: msg={{ item }}   with_items: foo 

The above tasks should generate the following output:

TASK: [set fact] ************************************************************** ok: [localhost]  TASK: [debug] ***************************************************************** ok: [localhost] => (item=one) => {     "item": "one",     "msg": "one" } ok: [localhost] => (item=two) => {     "item": "two",     "msg": "two" } ok: [localhost] => (item=three) => {     "item": "three",     "msg": "three" }