Run an Ansible Task Only When the Variable Contains a Specific String

If variable1 is a string, and you are searching for a substring in it, this should work:

when: '"value" in variable1'

if variable1 is an array or dict instead, in will search for the exact string as one of its items.

None of the above answers worked for me in ansible 2.3.0.0, but the following does:

when: variable1 | search("value")

In ansible 2.9 this is deprecated in favor of using ~ concatenation for variable replacement:

when: "variable1.find('v=' ~ value) == -1"

Other options:

when: "inventory_hostname in groups[sync_source]"

From Ansible 2.5

when: variable1 is search("value")

Some of the answers no longer work as explained.

Currently here is something that works for me in ansible 2.6.x

 when: register_var.stdout is search('some_string')

This example uses regex_search to perform a substring search.

- name: make conditional variable
  command: "file -s /dev/xvdf"
  register: fsm_out

- name: makefs
  command: touch "/tmp/condition_satisfied"
  when: fsm_out.stdout | regex_search(' data')

ansible version: 2.4.3.0

This works for me in Ansible 2.9:

variable1 =  
variable2 =  

when: ".com" in variable1

and for not:

when: not ".com" in variable2

use this

when: "{{ 'value' in variable1}}"

instead of

when: "'value' in {{variable1}}"

Also for string comparison you can use

when: "{{ variable1 == 'value' }}"

In Ansible version 2.9.2:

If your variable variable1 is declared:

when: "'value' in variable1"

If you registered variable1 then:

when: "'value' in variable1.stdout"

I used

failed_when: not(promtool_version.stdout.find('1.5.2') != -1)

means - failed only when the previously registered variable "promtool_version" doesn't contains string '1.5.2'.