Ansible - How to keep appending new keys to a dictionary when using set_fact module with with_items?
This can also be done without resorting to plugins, tested in Ansible 2.2.
---
- hosts: localhost
connection: local
vars:
some_value: 12345
dict: {}
tasks:
- set_fact:
dict: "{{ dict | combine( { item: some_value } ) }}"
with_items:
- 1
- 2
- 3
- debug: msg="{{ dict }}"
Alternatively, this can be written without the complex one-liner with an include file.
tasks:
- include: append_dict.yml
with_items: [1, 2, 3]
append_dict.yml:
- name: "Append dict: define helper variable"
set_fact:
_append_dict: "{ '{{ item }}': {{ some_value }} }"
- name: "Append dict: execute append"
set_fact:
dict: "{{ dict | combine( _append_dict ) }}"
Output:
TASK [debug]
*******************************************************************
ok: [localhost] => {
"msg": {
"1": "12345",
"2": "12345",
"3": "12345"
}
}
Single quotes '
around {{ some_value }}
are needed to store string values explicitly.
This syntax can also be used to append from a dict
elementwise using with_dict
by referring to item.key
and item.value
.
Manipulations like adding pre- and postfixes or hashes can be performed in the same step, for example
set_fact:
dict: "{{ dict | combine( { item.key + key_postfix: item.value + '_' + item.value | hash('md5') } ) }}"
Use a filter plugin.
First, make a new file in your ansible base dir called filter_plugins/makedict.py
.
Now create a new function called "makedict" (or whatever you want) that takes a value and a list and returns a new dictionary where the keys are the elements of the list and the value is always the same.
class FilterModule(object):
def filters(self):
return { 'makedict': lambda _val, _list: { k: _val for k in _list } }
Now you can use the new filter in the playbook to achieve your desired result:
- hosts: 127.0.0.1
connection: local
vars:
my_value: 12345
my_keys: [1, 2, 3]
tasks:
- set_fact: my_dict="{{ my_value | makedict(my_keys) }}"
- debug: msg="{{ item.key }}={{ item.value }}"
with_dict: "{{my_dict}}"
You can customize the location of the filter plugin using the filter_plugins
option in ansible.cfg
.