Since Ansible version 2.5 there is a lot of discussion and confusion
about the loop syntax.
There is also discussion if with_...: will be replaced by loop:
deprecating the with_... keywords. Even Ansibles documentation is not
clear about this.
Should I use loop: or with_...:, in fact nobody really knows.
What would the correct syntax be?
---
- name: Loops with with_ and lookup
hosts: localhost
connection: local
gather_facts: no
vars:
people:
- john
- paul
- mary
drinks:
- beer
- wine
- whisky
tasks:
- name: with nested
debug:
msg: "with_nested: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
with_nested:
- "{{ people }}"
- "{{ drinks }}"
- name: nested and loop
debug:
msg: "nested_loop: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
loop:
- "{{ people }}"
- "{{ drinks }}"
The best indication for this would be the Migrating from with_X to loop section in the Ansible documentation.
But to be sure if a certain syntax works, I created a playbook that tests all (OK, not all but a lot) different syntaxes and show the output. Enjoy!
---
- name: Loops with with_ and lookup, query and others
hosts: localhost
connection: local
gather_facts: no
vars:
beatles:
john: guitar - vocals
paul: bass - vocals
ringo: drums - vocals
george: guitar - vocals
people:
- john
- paul
- mary
drinks:
- beer
- wine
- whisky
tasks:
- name: with_items loop
debug:
msg: "with_items: item is '{{ item }}'"
with_items: "{{ people }}"
- name: with loop
debug:
msg: "loop: item is '{{ item }}'"
loop: "{{ people }}"
- name: with nested
debug:
msg: "with_nested: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
with_nested:
- "{{ people }}"
- "{{ drinks }}"
- name: nested and loop
debug:
msg: "nested_loop: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
loop:
- "{{ people }}"
- "{{ drinks }}"
# This example gives a Cartesian product of people with drinks. Way more than you want
#- name: nested and lookup (this is wrong!!!)
# debug:
# msg: "with_nested_lookup: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
# with_nested: "{{ lookup('nested', people, drinks, wantlist=True ) }}"
- name: nested with loop and lookup
debug:
msg: "nested_loop_lookup: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
loop: "{{ lookup('nested', people, drinks, wantlist=True ) }}"
- name: nested with loop and query
debug:
msg: "nested_loop_query: item[0] is '{{ item[0] }}' and item[1] is '{{ item[1] }}'"
loop: "{{ query('nested', people, drinks ) }}"
- name: with dict
debug:
msg: "with_dict: item.key is '{{ item.key }}' and item.value is '{{ item.value }}'"
with_dict: "{{ beatles }}"
- name: with dict lookup
debug:
msg: "with_dict_lookup: item.key is '{{ item.key }}' and item.value is '{{ item.value }}'"
loop: "{{ lookup('dict', beatles) }}"
- name: with dict query
debug:
msg: "with_dict_query: item.key is '{{ item.key }}' and item.value is '{{ item.value }}'"
loop: "{{ query('dict', beatles) }}"
- name: with dict2items
debug:
msg: "with_dict2items: item.key is '{{ item.key }}' and item.value is '{{ item.value }}'"
loop: "{{ beatles | dict2items }}"
- name: with sequence loop
debug:
msg: "with_sequence: item is '{{ item }}'"
# end is inclusive of the end point
with_sequence:
start=0
end=10
stride=2
format=guru_%02x
- name: with sequence loop and lookup
debug:
msg: "sequence_lookup: item is '{{ item }}'"
# end is inclusive of the end point
loop: "{{ lookup('sequence', 'start=0 end=10 stride=2 format=guru_%02x', wantlist=True) }}"
- name: with sequence loop and query
debug:
msg: "sequence_query: item is '{{ item }}'"
# end is inclusive of the end point
loop: "{{ query('sequence', 'start=0 end=10 stride=2 format=guru_%02x') }}"
- name: with_sequence loop and range
debug:
msg: "loop_range: item is {{ 'guru_%02x' | format(item) }}"
# range is exclusive of the end point
loop: "{{ range(0, 10 + 1, 2) | list }}"