ansible.utils.index_of lookup – Find the indices of items in a list matching some criteria

Note

This lookup plugin is part of the ansible.utils collection (version 2.7.0).

You might already have this collection installed if you are using the ansible package. It is not included in ansible-core. To check whether it is installed, run ansible-galaxy collection list.

To install it, use: ansible-galaxy collection install ansible.utils.

To use it in a playbook, specify: ansible.utils.index_of.

New in ansible.utils 1.0.0

Synopsis

  • This plugin returns the indices of items matching some criteria in a list.

  • When working with a list of dictionaries, the key to evaluate can be specified.

  • index_of is also available as a filter plugin for convenience.

  • Using the parameters below- lookup('ansible.utils.index_of', data, test, value, key, fail_on_missing, wantlist).

Parameters

Parameter

Comments

data

list / elements=any / required

A list of items to enumerate and test against.

fail_on_missing

boolean

When provided a list of dictionaries, fail if the key is missing from one or more of the dictionaries.

Choices:

  • false

  • true

key

string

When the data provided is a list of dictionaries, run the test against this dictionary key.

When using a key, the data must only contain dictionaries.

See fail_on_missing below to determine the behaviour when the key is missing from a dictionary in the data.

test

string / required

The name of the test to run against the list, a valid jinja2 test or ansible test plugin.

Jinja2 includes the following tests http://jinja.palletsprojects.com/templates/#builtin-tests.

An overview of tests included in ansible https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html.

value

any

The value used to test each list item against.

Not required for simple tests (e.g. true, false, even, odd)

May be a string, boolean, number, regular expression dict and so on, depending on the test used.

wantlist

boolean

When only a single entry in the data is matched, the index of that entry is returned as an integer.

If set to True, the return value will always be a list, even if only a single entry is matched.

This can also be accomplished using query or q instead of lookup.

https://docs.ansible.com/ansible/latest/plugins/lookup.html

Choices:

  • false

  • true

Examples

#### Simple examples

- ansible.builtin.set_fact:
    data:
    - 1
    - 2
    - 3

- name: Find the index of 2
  ansible.builtin.set_fact:
    indices: "{{ lookup('ansible.utils.index_of', data, 'eq', 2) }}"

# TASK [Find the index of 2] *************************************************
# ok: [nxos101] => changed=false
#   ansible_facts:
#     indices: '1'

- name: Find the index of 2, ensure list is returned
  ansible.builtin.set_fact:
    indices: "{{ lookup('ansible.utils.index_of', data, 'eq', 2, wantlist=True) }}"

# TASK [Find the index of 2, ensure list is returned] ************************
# ok: [nxos101] => changed=false
#   ansible_facts:
#     indices:
#     - 1

- name: Find the index of 3 using the long format
  ansible.builtin.set_fact:
    indices: "{{ lookup('ansible.utils.index_of', data=data, test='eq', value=value, wantlist=True) }}"
  vars:
    value: 3

# TASK [Find the index of 3 using the long format] ***************************
# ok: [nxos101] => changed=false
#   ansible_facts:
#     indices:
#     - 2

- name: Find numbers greater than 1, using loop
  debug:
    msg: "{{ data[item] }} is {{ test }} than {{ value }}"
  loop: "{{ lookup('ansible.utils.index_of', data, test, value) }}"
  vars:
    test: '>'
    value: 1

# TASK [Find numbers great than 1, using loop] *******************************
# ok: [sw01] => (item=1) =>
#   msg: 2 is > than 1
# ok: [sw01] => (item=2) =>
#   msg: 3 is > than 1

- name: Find numbers greater than 1, using with
  debug:
    msg: "{{ data[item] }} is {{ params.test }} than {{ params.value }}"
  with_ansible.utils.index_of: "{{ params }}"
  vars:
    params:
      data: "{{ data }}"
      test: '>'
      value: 1

# TASK [Find numbers greater than 1, using with] *****************************
# ok: [nxos101] => (item=1) =>
#   msg: 2 is > than 1
# ok: [nxos101] => (item=2) =>
#   msg: 3 is > than 1


#### Working with lists of dictionaries

- ansible.builtin.set_fact:
    data:
    - name: sw01.example.lan
      type: switch
    - name: rtr01.example.lan
      type: router
    - name: fw01.example.corp
      type: firewall
    - name: fw02.example.corp
      type: firewall

- name: Find the index of all firewalls using the type key
  ansible.builtin.set_fact:
    firewalls: "{{ lookup('ansible.utils.index_of', data, 'eq', 'firewall', 'type') }}"

# TASK [Find the index of all firewalls using the type key] ******************
# ok: [nxos101] => changed=false
#   ansible_facts:
#     firewalls:
#     - 2
#     - 3

- name: Find the index of all firewalls, use in a loop
  debug:
    msg: "The type of {{ device_type }} at index {{ item }} has name {{ data[item].name }}."
  loop: "{{ lookup('ansible.utils.index_of', data, 'eq', device_type, 'type') }}"
  vars:
    device_type: firewall

# TASK [Find the index of all firewalls, use in a loop, as a filter] *********
# ok: [nxos101] => (item=2) =>
#   msg: The type of firewall at index 2 has name fw01.example.corp.
# ok: [nxos101] => (item=3) =>
#   msg: The type of firewall at index 3 has name fw02.example.corp.

- name: Find the index of all devices with a .corp name
  debug:
    msg: "The device named {{ data[item].name }} is a {{ data[item].type }}"
  loop: "{{ lookup('ansible.utils.index_of', data, 'regex', expression, 'name') }}"
  vars:
    expression: '\.corp$' # ends with .corp

# TASK [Find the index of all devices with a .corp name] *********************
# ok: [nxos101] => (item=2) =>
#   msg: The device named fw01.example.corp is a firewall
# ok: [nxos101] => (item=3) =>
#   msg: The device named fw02.example.corp is a firewall


#### Working with complex structures from resource modules

- name: Retrieve the current L3 interface configuration
  cisco.nxos.nxos_l3_interfaces:
    state: gathered
  register: current_l3

# TASK [Retrieve the current L3 interface configuration] *********************
# ok: [sw01] => changed=false
#   gathered:
#   - name: Ethernet1/1
#   - name: Ethernet1/2
#   <...>
#   - name: Ethernet1/128
#   - ipv4:
#     - address: 192.168.101.14/24
#     name: mgmt0

- name: Find the indices interfaces with a 192.168.101.xx ip address
  ansible.builtin.set_fact:
    found: "{{ found + entry }}"
  with_indexed_items: "{{ current_l3.gathered }}"
  vars:
    found: []
    ip: '192.168.101.'
    address: "{{ lookup('ansible.utils.index_of', item.1.ipv4|d([]), 'search', ip, 'address', wantlist=True) }}"
    entry:
    - interface_idx: "{{ item.0 }}"
      address_idxs: "{{ address }}"
  when: address

# TASK [debug] ***************************************************************
# ok: [sw01] =>
#   found:
#   - address_idxs:
#     - 0
#     interface_idx: '128'

- name: Show all interfaces and their address
  debug:
    msg: "{{ interface.name }} has ip {{ address }}"
  loop: "{{ found|subelements('address_idxs') }}"
  vars:
    interface: "{{ current_l3.gathered[item.0.interface_idx|int] }}"
    address: "{{ interface.ipv4[item.1].address }}"

# TASK [Show all interfaces and their address] *******************************
# ok: [nxos101] => (item=[{'interface_idx': '128', 'address_idxs': [0]}, 0]) =>
#   msg: mgmt0 has ip 192.168.101.14/24


#### Working with deeply nested data

- ansible.builtin.set_fact:
    data:
      interfaces:
        interface:
          - config:
              description: configured by Ansible - 1
              enabled: True
              loopback-mode: False
              mtu: 1024
              name: loopback0000
              type: eth
            name: loopback0000
            subinterfaces:
              subinterface:
                - config:
                    description: subinterface configured by Ansible - 1
                    enabled: True
                    index: 5
                  index: 5
                - config:
                    description: subinterface configured by Ansible - 2
                    enabled: False
                    index: 2
                  index: 2
          - config:
              description: configured by Ansible - 2
              enabled: False
              loopback-mode: False
              mtu: 2048
              name: loopback1111
              type: virt
            name: loopback1111
            subinterfaces:
              subinterface:
                - config:
                    description: subinterface configured by Ansible - 3
                    enabled: True
                    index: 10
                  index: 10
                - config:
                    description: subinterface configured by Ansible - 4
                    enabled: False
                    index: 3
                  index: 3


- name: Find the description of loopback111, subinterface index 10
  debug:
    msg: |-
      {{ data.interfaces.interface[int_idx|int]
          .subinterfaces.subinterface[subint_idx|int]
            .config.description }}
  vars:
    # the values to search for
    int_name: loopback1111
    sub_index: 10
    # retrieve the index in each nested list
    int_idx: |
      {{ lookup('ansible.utils.index_of',
             data.interfaces.interface,
                 'eq', int_name, 'name') }}
    subint_idx: |
      {{ lookup('ansible.utils.index_of',
             data.interfaces.interface[int_idx|int].subinterfaces.subinterface,
                 'eq', sub_index, 'index') }}

# TASK [Find the description of loopback111, subinterface index 10] ************
# ok: [sw01] =>
#   msg: subinterface configured by Ansible - 3

Return Value

Key

Description

Return value

string

One or more zero-based indicies of the matching list items.

See wantlist if a list is always required.

Returned: success

Authors

  • Bradley Thornton (@cidrblock)

Hint

Configuration entries for each entry type have a low to high priority order. For example, a variable that is lower in the list will override a variable that is higher up.