lists_mergeby – Merge two or more lists of dictionaries by a given attribute

Note

This filter plugin is part of the middleware_automation.amq collection.

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 middleware_automation.amq.

To use it in a playbook, specify: middleware_automation.amq.lists_mergeby.

New in middleware_automation.amq 2.0.0

Synopsis

• Merge two or more lists by attribute index. Optional parameters recursive and list_merge control the merging of the lists in values. The function merge_hash from ansible.utils.vars is used. To learn details on how to use the parameters recursive and list_merge see Ansible User’s Guide chapter “Using filters to manipulate data” section “Combining hashes/dictionaries”.

Input

This describes the input of the filter, the value before | middleware_automation.amq.lists_mergeby.

Parameter	Comments
Input list / elements=dictionary / required	A list of dictionaries.

Positional parameters

This describes positional parameters of the filter. These are the values positional1, positional2 and so on in the following example: input | middleware_automation.amq.lists_mergeby(positional1, positional2, ...)

Parameter	Comments
another_list list / elements=dictionary	Another list of dictionaries. This parameter can be specified multiple times.
index string / required	The dictionary key that must be present in every dictionary in every list that is used to merge the lists.

Keyword parameters

This describes keyword parameters of the filter. These are the values key1=value1, key2=value2 and so on in the following example: input | middleware_automation.amq.lists_mergeby(key1=value1, key2=value2, ...)

Parameter	Comments
list_merge string	Modifies the behaviour when the dictionaries (hashes) to merge contain arrays/lists. Choices: "replace" ← (default) "keep" "append" "prepend" "append_rp" "prepend_rp"
recursive boolean	Should the combine recursively merge nested dictionaries (hashes). Note: It does not depend on the value of the hash_behaviour setting in ansible.cfg. Choices: false ← (default) true

Notes

Note

• When keyword and positional parameters are used together, positional parameters must be listed before keyword parameters: input | middleware_automation.amq.lists_mergeby(positional1, positional2, key1=value1, key2=value2)

Examples

- name: Merge two lists
  ansible.builtin.debug:
    msg: >-
      {{ list1 | middleware_automation.amq.lists_mergeby(
                    list2,
                    'index',
                    recursive=True,
                    list_merge='append'
                 ) }}"
  vars:
    list1:
      - index: a
        value: 123
      - index: b
        value: 42
    list2:
      - index: a
        foo: bar
      - index: c
        foo: baz
  # Produces the following list of dictionaries:
  #   {
  #     "index": "a",
  #     "foo": "bar",
  #     "value": 123
  #   },
  #   {
  #     "index": "b",
  #     "value": 42
  #   },
  #   {
  #     "index": "c",
  #     "foo": "baz"
  #   }

Return Value

Key	Description
Return value list / elements=dictionary	The merged list. Returned: success

Authors

• Vladimir Botka (@vbotka)

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.