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@rektide
Last active December 15, 2021 16:39
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Ansible dictionary iteration
---
- hosts: all
vars:
places:
alpha: /home
epsilon: /nopenopenope
tasks:
- name: "changed_when depending on result, in with_items"
shell: "[[ '{{item}}' != 'alpha' ]]"
with_items: "{{ places.keys() }}"
register: places_arr
changed_when: places_arr.rc != 0
failed_when: False
- name: "print places_arr result"
debug:
msg: "{{places_arr.results}}"
- name: "changed_when depending on result, in with_dict"
stat:
path: "{{item.value}}"
with_dict: "{{places}}"
register: places_dict
changed_when: not places_dict.stat.exists
- name: "print places_dict result"
debug:
msg: "{{places_dict.results}}"
- name: "iterate through with_dict, via re-indexing original array (bad way to iterate through with_dict results)"
debug:
msg: "{{ places[item[1]] }} {{ 'existed' if places_dict.results[item[0]].stat.exists else 'didnt exist' }}"
with_indexed_items: "{{ places.keys() }}"
- name: "iterate through with_dict, using result's item property (good way to iterate through with_dict results)"
debug:
msg: "{{ item.item.value }} {{ 'existed' if item.stat.exists else 'didnt exist' }}"
with_items: "{{places_dict.results}}"
# originally i was doing this because i did not see that results included an .item property, which made iterating through the results, as above, hard
- name: "a dict iterated via with with_indexed_items"
stat:
path: "{{ places[item[1]] }}"
with_indexed_items: "{{ places.keys() }}"
register: places_indexed
changed_when: not places_indexed.stat.exists
- name: "print places_indexed result"
debug: msg="{{places_indexed.results}}"
- name: "iterate through indexed results"
debug:
msg: "{{ places[item.item[1]] }} {{ 'existed' if item.stat.exists else 'didnt exist' }}"
with_items: "{{places_indexed.results}}"
@rektide
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rektide commented Feb 2, 2017

Originally this was an example of me not getting how to iterate though a dictionary & do a changed_when for each entry.
But ok! bcoca told me what I wasn't getting: it's only after looping that results are turned into an array. While looping the register variable is set to the current iterations result.

After understanding how to issue a changed_when, I was still not sure how I would iterate through the results of a with_dict at a latter time, since the results are recorded as an array. I assumed I would still have to use the _with_indexed_items/myDict.keys() form to give me a primary key- an enumerated number, as well as the dict's key as items. But this turns out to not be necesssary: results are stored with a .item property that tells you what the current element is when processing results.

I have filed ansible/ansible#20991 to try to improve the documentation on the first of these issues. And I've elaborated a bit further on techniques for iterating through dicts in this gist, for reference sake.

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