ansible/docs/docsite/rst/playbooks_tests.rst

Tests

Topics

Tests in Jinja2 are a way of evaluating template expressions and returning True or False. Jinja2 ships with many of these. See builtin tests in the official Jinja2 template documentation. Tests are very similar to filters and are used mostly the same way, but they can also be used in list processing filters, like C(map()) and C(select()) to choose items in the list.

Like all templating, tests always execute on the Ansible controller, not on the target of a task, as they test local data.

In addition to those Jinja2 tests, Ansible supplies a few more and users can easily create their own.

Testing strings

To match strings against a substring or a regex, use the "match" or "search" filter:

vars:
  url: "http://example.com/users/foo/resources/bar"

tasks:
    - debug: "msg='matched pattern 1'"
      when: url | match("http://example.com/users/.*/resources/.*")

    - debug: "msg='matched pattern 2'"
      when: url | search("/users/.*/resources/.*")

    - debug: "msg='matched pattern 3'"
      when: url | search("/users/")

'match' requires a complete match in the string, while 'search' only requires matching a subset of the string.

Version Comparison

1.6

To compare a version number, such as checking if the ansible_distribution_version version is greater than or equal to '12.04', you can use the version_compare filter.

The version_compare filter can also be used to evaluate the ansible_distribution_version:

{{ ansible_distribution_version | version_compare('12.04', '>=') }}

If ansible_distribution_version is greater than or equal to 12, this filter returns True, otherwise False.

The version_compare filter accepts the following operators:

<, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne

This test also accepts a 3rd parameter, strict which defines if strict version parsing should be used. The default is False, but this setting as True uses more strict version parsing:

{{ sample_version_var | version_compare('1.0', operator='lt', strict=True) }}

Group theory tests

2.1

To see if a list includes or is included by another list, you can use 'issubset' and 'issuperset':

vars:
    a: [1,2,3,4,5]
    b: [2,3]
tasks:
    - debug: msg="A includes B"
      when: a|issuperset(b)

    - debug: msg="B is included in A"
      when: b|issubset(a)

2.4

You can use any and all to check if any or all elements in a list are true or not:

vars:
  mylist:
      - 1
      - 3 == 3
      - True
  myotherlist:
      - False
      - True
tasks:

  - debug: msg="all are true!"
    when: mylist is all

  - debug: msg="at least one is true"
    when: myotherlist|any

Testing paths

The following tests can provide information about a path on the controller:

- debug: msg="path is a directory"
  when: mypath|is_dir

- debug: msg="path is a file"
  when: mypath|is_file

- debug: msg="path is a symlink"
  when: mypath|is_link

- debug: msg="path already exists"
  when: mypath|exists

- debug: msg="path is {{ (mypath|is_abs)|ternary('absolute','relative')}}"

- debug: msg="path is the same file as path2"
  when: mypath|samefile(path2)

- debug: msg="path is a mount"
  when: mypath|is_mount

Task results

The following tasks are illustrative of the tests meant to check the status of tasks:

tasks:

  - shell: /usr/bin/foo
    register: result
    ignore_errors: True

  - debug: msg="it failed"
    when: result|failed

  # in most cases you'll want a handler, but if you want to do something right now, this is nice
  - debug: msg="it changed"
    when: result|changed

  - debug: msg="it succeeded in Ansible >= 2.1"
    when: result|succeeded

  - debug: msg="it succeeded"
    when: result|success

  - debug: msg="it was skipped"
    when: result|skipped

Note

From 2.1, you can also use success, failure, change, and skip so that the grammar matches, for those who need to be strict about it.

playbooks

An introduction to playbooks

playbooks_conditionals

Conditional statements in playbooks

playbooks_variables

All about variables

playbooks_loops

Looping in playbooks

playbooks_reuse_roles

Playbook organization by roles

playbooks_best_practices

Best practices in playbooks

User Mailing List

Have a question? Stop by the google group!

irc.freenode.net

#ansible IRC chat channel