Using parse_xml in an Ansible playbook - ansible

Question

I've been trying to parse XML data in Ansible. I can get it to work using the xml module but I think that using parse_xml would better suit my needs.
I don't seem to be able to match any of the data in the xml with my specs file.
Here is the xml data:
<data xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\" xmlns:nc=\"urn:ietf:params:xml:ns:netconf:base:1.0\">
<ntp xmlns=\"http://cisco.com/ns/yang/Cisco-IOS-XR-ip-ntp-oper\">
<nodes>
<node>
<node>0/0/CPU0</node>
<associations>
<is-ntp-enabled>true</is-ntp-enabled>
<sys-leap>ntp-leap-no-warning</sys-leap>
<peer-summary-info>
<peer-info-common>
<host-mode>ntp-mode-client</host-mode>
<is-configured>true</is-configured>
<address>10.1.1.1</address>
<reachability>0</reachability>
</peer-info-common>
<time-since>-1</time-since>
</peer-summary-info>
<peer-summary-info>
<peer-info-common>
<host-mode>ntp-mode-client</host-mode>
<is-configured>true</is-configured>
<address>172.16.252.29</address>
<reachability>255</reachability>
</peer-info-common>
<time-since>991</time-since>
</peer-summary-info>
</associations>
</node>
</nodes>
</ntp>
</data>
This is what the spec file looks like:
---
vars:
ntp_peers:
address: "{{ item.address }}"
reachability: "{{ item.reachability}}"
keys:
result:
value: "{{ ntp_peers }}"
top: data/ntp/nodes/node/associations
items:
address: peer-summary-info/peer-info-common/address
reachability: peer-summary-info/peer-info-common/reachability
and the task in the yaml file:
- name: parse ntp reply
set_fact:
parsed_ntp_data: "{{ NTP_STATUS.stdout | parse_xml('specs/iosxr_ntp.yaml') }}"
but the data does not return any results:
TASK [debug parsed_ntp_data] **************************************************************************************************************************************************************************
ok: [core-rtr01] => {
"parsed_ntp_data": {
"result": []
}
}
ok: [dist-rtr01] => {
"parsed_ntp_data": {
"result": []
}
}

Answer 1

I had never seen parse_xml before, so that was a fun adventure
There appear to be two things conspiring against you: the top: key is evaluated from the root Element, and your XML (unlike the rest of the examples) uses XML namespaces (the xmlns= bit) which means your XPaths have to be encoded in the Element.findall manner
For the first part, since Element.findall is run while sitting on the <data> Element, that means one cannot reference data/... in an XPath because that would be applicable to a structure <data><data>. I tried being sneaky by just making the XPath absolute /data/... but Python's XPath library throws up in that circumstance. So, at the very least your top: key needs to not start with data anything
Then, the xmlns= in your snippet stood out to me because that means those element's names are actually NS+":"+localName for every element, and thus an XPath of ntp does NOT match ns0:ntp because they're considered completely separate names (that being the point of the namespace, after all). It may very well be possible to use enough //*[localname() = "ntp"] silliness to avoid having to specify the namespace over and over, but I didn't try it
Again, as a concession to Python's XPath library, they encode the fully qualified name in an xpath as {the-namespace}local-name and there does not seem to be any way short of modifying network.py to pass in namespaces :-(
Thus, the "hello world" version that I used to confirm my theory:
vars:
ntp_peers:
address: "{{ item.address }}"
keys:
result:
value: "{{ ntp_peers }}"
top: '{http://cisco.com/ns/yang/Cisco-IOS-XR-ip-ntp-oper}ntp/{http://cisco.com/ns/yang/Cisco-IOS-XR-ip-ntp-oper}nodes/{http://cisco.com/ns/yang/Cisco-IOS-XR-ip-ntp-oper}node'
items:
address: '{http://cisco.com/ns/yang/Cisco-IOS-XR-ip-ntp-oper}node'
cheerfully produced
ok: [localhost] => {
"msg": {
"result": [
{
"address": "0/0/CPU0"
}
]
}
}