Re: [ansible-project] deferred evaluation (?)
Create a template. For example,
shell> cat create_test.j2
{% for i in strings %}
{{ i }} = {{ '{{' }} {{ i }} {{ '}}' }}
{% endfor %}
Then, the below playbook
shell> cat pb.yml
- hosts: localhost
tasks:
- template:
src: create_test.j2
dest: /tmp/test.j2
vars:
strings:
- '0'
- '1'
- "['aa', 'bb', 'cc']|intersect(['bb', 'cc'])"
- "['aa', 'bb', 'cc']|intersect(['bb', 'cc'])|length > 0"
- debug:
msg: "{{ lookup('template', '/tmp/test.j2') }}"
gives abridged
msg: |-
0 = 0
1 = 1
['aa', 'bb', 'cc']|intersect(['bb', 'cc']) = ['bb', 'cc']
['aa', 'bb', 'cc']|intersect(['bb', 'cc'])|length > 0 = True
--
Vladimir Botka
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Re: [ansible-project] deferred evaluation (?)
Sure. Here's a complete example where the debug task's output msg
contains exactly what I want. However, instead of each item being a
3-element list of strings, I want to pass in a single string, and use
that string in various ways within the msg: expressions to accomplish
the same thing.
To be clear: as presented below, this problem isn't worth solving. After
all, there's the playbook down below already! But that's not the point.
The point is to understand effective /run-time/ techniques to build
strings containing Jinja2 expressions and have them evaluated.
("Templated" I guess is the verb rather than "evaluated," but that feels
backwards. In my brain, "to template" means to examine a sufficiently
large set of outputs and create a template adequate to reproduce those
outputs from reasonable inputs. But I digress.)
Apparently it's possible to write such strings to a file and use
lookup('template',tmpfilename), but there doesn't seem to be the
equivalent of lookup('template',jinja2_expression_string). Not that I
have found anyway.
[utoddl@tango ansible]$*cat deferred.yml*
---
# deferred.yml
- name: Deferred evaluation demo
hosts: localhost
gather_facts: false
tasks:
- name: Evaluate booleanness of various expressions
ansible.builtin.debug:
msg:
- '{{ item.0 }}'
- '{{ item.1 }}'
- '{{ item.2 }}'
loop:
- [ "0",
"{{ 0 }}",
"{{ 0 | bool }}"]
- [ "1",
"{{ 1 }}",
"{{ 1 | bool }}"]
- [ "2",
"{{ 2 }}",
"{{ 2 | bool }}"]
- [ "['aa', 'bb', 'cc'] | intersect(['bb', 'cc'])",
"{{ ['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) }}",
"{{ ['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | bool }}"]
- [ "['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length > 0",
"{{ ['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length > 0 }}",
"{{ ['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length > 0 | bool
}}"]
[utoddl@tango ansible]$*ansible-playbook deferred.yml*
PLAY [Deferred evaluation demo]
*
TASK [Evaluate booleanness of various expressions]
**
ok: [localhost] => (item=['0', '0', False]) => {
"msg": [
"0",
"0",
false
]
}
ok: [localhost] => (item=['1', '1', True]) => {
"msg": [
"1",
"1",
true
]
}
ok: [localhost] => (item=['2', '2', False]) => {
"msg": [
"2",
"2",
false
]
}
ok: [localhost] => (item=["['aa', 'bb', 'cc'] | intersect(['bb', 'cc'])", ['bb',
'cc'], False]) => {
"msg": [
"['aa', 'bb', 'cc'] | intersect(['bb', 'cc'])",
[
"bb",
"cc"
],
false
]
}
ok: [localhost] => (item=["['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length >
0", True, True]) => {
"msg": [
"['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length > 0",
true,
true
]
}
PLAY RECAP
**
localhost : ok=1changed=0unreachable=0failed=0
skipped=0rescued=0ignored=0
On 7/27/23 6:03 PM, Vladimir Botka wrote:
post expected result
--
Todd
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Re: [ansible-project] deferred evaluation (?)
post expected result -- Vladimir Botka -- You received this message because you are subscribed to the Google Groups "Ansible Project" group. To unsubscribe from this group and stop receiving emails from it, send an email to ansible-project+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/20230728000322.23e6f83b%40gmail.com. pgpsIXqSvv9xn.pgp Description: OpenPGP digital signature
Re: [ansible-project] deferred evaluation (?)
I'm confused. The template lookup wants a [list of] file[s]. I'd rather not write these strings out to temp files just to get them templated. Or am I misinterpreting your suggestion? On Thursday, July 27, 2023 at 4:52:24 PM UTC-4 Brian Coca wrote: > try the template lookup > > -- > -- > Brian Coca > > -- You received this message because you are subscribed to the Google Groups "Ansible Project" group. To unsubscribe from this group and stop receiving emails from it, send an email to ansible-project+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/882015ee-42c8-42db-828d-e1b6a4697e5dn%40googlegroups.com.
Re: [ansible-project] deferred evaluation (?)
try the template lookup -- -- Brian Coca -- You received this message because you are subscribed to the Google Groups "Ansible Project" group. To unsubscribe from this group and stop receiving emails from it, send an email to ansible-project+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/ansible-project/CACVha7d_Uenwa9KKNScbC7RXfuxzpg9FM-%3D9cQa_9_FhROH1NQ%40mail.gmail.com.
[ansible-project] deferred evaluation (?)
I'm trying to loop over a set of strings with ansible.builtin.debug, and I
want to produce a three-part message for each string, like this:
- name: Demo expressions
ansible.builtin.debug:
msg:
- '{{ item }}'
- '*evaluate item as a Jinja2 expression*'
- '*like previous, but with "| bool" appended*'
loop:
- "0"
- "1"
- "2"
- "['aa', 'bb', 'cc'] | intersect(['bb', 'cc'])"
- "['aa', 'bb', 'cc'] | intersect(['bb', 'cc']) | length > 0"
The first part of the message should show the string, and it does.
The second part somehow needs to show the result of evaluating the string
as a Jinja2 expression.
The third part is supposed to append "| bool" onto the string, evaluate
_that_ as a Jinja2 expression, and show the result.
I feel like there should be some way to do this with lookup('items',...),
but I'm having no luck. I'd appreciate any suggestions. Thanks,
--
Todd
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