Difficulty Parsing Ansible Output - ansible

Question

[ansible 2.9.6, Ubuntu 20.04]
This seems pretty straightforward, but I keep getting an error message saying:
fatal: [192.168.254.100]: FAILED! => {"msg": "template error while templating string: expected name or number. String: {{ipv4addrs.'host[0]'}}"}
Here's my ansible playbook:
---
- hosts: nios
connection: local
vars:
nios_provider:
host: 192.x.x.x
username: xxx
password: xxx
wapi_version: "2.11.2"
tasks:
- name: Find client app server records
set_fact:
recs: "{{ lookup('nios', 'record:host', filter={'name~':'sdk' }, provider=nios_provider) }}"
- name: check return
debug:
msg: "{{ recs }}"
- name: get host name
debug:
var: ipv4addrs.'host[0]'
And here's the output:
TASK [check return] **************************************************************************************************************************************************************
ok: [192.x.x.x] => {
"msg": [
{
"_ref": "record:host/ZG5zLmhvc3QkLl9kZWZhdWx0LmNvbS5lYWdsZWFjY2Vzcy5zZGstZDAwMQ:sdk-d001.somename.com/default",
"ipv4addrs": [
{
"_ref": "record:host_ipv4addr/ZG5zLmhvc3RfYWRkcmVzcyQuX2RlZmF1bHQuY29tLmVhZ2xlYWNjZXNzLnNkay1kMDAxLjEwLjcwLjAuMS4:10.70.0.1/sdk-d001.somename.com/default",
"configure_for_dhcp": false,
"host": "sdk-d001.somename.com",
"ipv4addr": "10.70.0.1"
}
],
"name": "sdk-d001.somename.com",
"view": "default"
},
{
"_ref": "record:host/ZG5zLmhvc3QkLl9kZWZhdWx0LmNvbS5lYWdsZWFjY2Vzcy5zZGstZDAwMg:sdk-d002.somename.com/default",
"ipv4addrs": [
{
"_ref": "record:host_ipv4addr/ZG5zLmhvc3RfYWRkcmVzcyQuX2RlZmF1bHQuY29tLmVhZ2xlYWNjZXNzLnNkay1kMDAyLjEwLjcwLjAuMi4:10.70.0.2/sdk-d002.somename.com/default",
"configure_for_dhcp": false,
"host": "sdk-d002.somename.com",
"ipv4addr": "10.70.0.2"
}
],
"name": "sdk-d002.somename.com",
"view": "default"
}
]
}
TASK [get host name] ***************************************************************************************************************************************************************
fatal: [192.168.254.100]: FAILED! => {"msg": "template error while templating string: expected name or number. String: {{ipv4addrs.'host[0]'}}"}
My objective is to find all of the host names beginning with (for example) "sdk". There may be 1 or several. And then I want to get the full name and ip address captured as variables. I have tried lots of different options: rec.ipv4addrs[0].host, ipv4addrs[0].host, rec.ipv4addrs[0].'host', rec.ipv4addrs[0].['host'] . . . but I cannot find the proper syntax.
This appears to be an array of dict blocks with an ipv4addrs array within it. So the first thing I tried was "ipv4addrs[0]['host']" with no joy.
Thanks in advance for the help.

Answer 1

You're trying to make use of a variable called ipv4addrs, but you
haven't defined any variables with that name. From the previous
debug task you apparently have a variable named recs, which is a
list of dictionaries each of which contains an ipv4addrs attribute.
If you wanted to look up the host attribute for each record in
recs, you could write something like this:
- name: get host name
debug:
var: item.ipv4addrs[0].host
loop: "{{ recs }}"
If you wanted the ipv4addrs.host value from the first record, you
could write:
- name: get host name
debug:
var: recs[0].ipv4addrs[0].host
The error you're seeing stems from the fact that the expression
ipv4addrs.'host[0]' doesn't make any sense; that's not a syntax that
Ansible supports. You can't use a string with dot-notation like that.