Ansible JSON parsing empty string - ansible

Question

I am trying to learn JSON parsing using jmesquery in Ansible.
Please consider the following play:
---
- name: GET ALL THE INTERFACES
junos_command:
commands: show configuration interfaces | display json
register: A
- name: DISPLAY VARIABLE A CONTENTS
debug:
var: A.stdout_lines
- name: JOSN QUERY TO STORE PORTS IN NEW VARIABLE ALL_PORTS
set_fact:
ALL_PORTS: "{{ A.stdout_lines | json_query(jmesquery) }}"
vars:
jmesquery: 'configuration.interfaces.interface[*].name'
- name: DISPLAY VARIABLE ALL_PORTS CONTENTS
debug:
var: ALL_PORTS
#
Based on the JSON query, the port ge-0/0/0 will be stored in ALL_PORT, but we do not see that when we run the playbook, debug on ALL_PORT shows it is empty.
PLAY [ROUTER-STIG-PLAYBOOK] ************************************************************************************************
TASK [STIG_ROUTER : GET ALL THE INTERFACES] ********************************************************************************
ok: [192.168.22.9]
TASK [STIG_ROUTER : DISPLAY VARIABLE A CONTENTS] ***************************************************************************
ok: [192.168.22.9] => {
"A.stdout_lines": [
{
"configuration": {
"#": {
"junos:changed-localtime": "2020-05-10 11:14:49 UTC",
"junos:changed-seconds": "1589109289",
"xmlns": "http://xml.juniper.net/xnm/1.1/xnm"
},
"interfaces": {
"interface": [
{
"name": "ge-0/0/0",
"unit": [
{
"family": {
"inet": {
"address": [
{
"name": "192.168.22.9/24"
}
]
}
},
"name": 0
}
]
}
]
},
"security": {
"policies": {
"global": {
"policy": [
{
"match": {
"application": [
"any"
],
"destination-address": [
"any"
],
"source-address": [
"any"
]
},
"name": "TEST",
"then": {
"permit": [
null
]
}
}
]
}
},
"screen": {
"ids-option": [
{
"icmp": {
"ping-death": [
null
]
},
"ip": {
"source-route-option": [
null
],
"tear-drop": [
null
]
},
"name": "untrust-screen",
"tcp": {
"land": [
null
],
"syn-flood": {
"alarm-threshold": 1024,
"attack-threshold": 200,
"destination-threshold": 2048,
"queue-size": 2000,
"source-threshold": 1024,
"timeout": 20
}
}
}
]
},
"zones": {
"security-zone": [
{
"name": "trust",
"tcp-rst": [
null
]
},
{
"name": "untrust",
"screen": "untrust-screen"
},
{
"host-inbound-traffic": {
"protocols": [
{
"name": "all"
}
],
"system-services": [
{
"name": "all"
}
]
},
"interfaces": [
{
"name": "ge-0/0/0.0"
}
],
"name": "A"
}
]
}
},
"system": {
"license": {
"autoupdate": {
"url": [
{
"name": "https://ae1.juniper.net/junos/key_retrieval"
}
]
}
},
"root-authentication": {
"encrypted-password": "$6$thcHCjAV$e3o5ZRNWv7WtysOxuKpBP2X0cA3QDNtWYyCSBAUkImSEsulEGTgfwEQBa12Wll0fegpwvZfTHLvCbDUIW1n211"
},
"services": {
"ftp": [
null
],
"netconf": {
"ssh": [
null
]
},
"ssh": {
"root-login": "allow"
}
},
"syslog": {
"file": [
{
"contents": [
{
"any": [
null
],
"name": "any"
},
{
"info": [
null
],
"name": "authorization"
}
],
"name": "messages"
},
{
"contents": [
{
"any": [
null
],
"name": "interactive-commands"
}
],
"name": "interactive-commands"
}
],
"user": [
{
"contents": [
{
"emergency": [
null
],
"name": "any"
}
],
"name": "*"
}
]
}
},
"version": "20191026.124700_builder.r1063854"
}
}
]
}
TASK [STIG_ROUTER : JOSN QUERY TO STORE PORTS IN NEW VARIABLE ALL_PORTS] ***************************************************
ok: [192.168.22.9]
TASK [STIG_ROUTER : DISPLAY VARIABLE ALL_PORTS CONTENTS] *******************************************************************
ok: [192.168.22.9] => {
"ALL_PORTS": ""
}
#
I used online JSON query tester.
https://jsonpath.com/
When I checked my my query "configuration.interfaces.interface[*].name" against A.stdout_lines, I found the expected response i.e
[
ge-0/0/0
]
Any feedback/guidance is appreciated!!
Have a good weekend!!

Answer 1

Your JMESPath may very well be correct for one object but as its name implies, and as your debug: var=A.stdout_lines shows, stdout_lines is a list
So, you can do one of several things:
recognize that your stdout_lines only contains one object and just feed that into json_query as {{ A.stdout_lines[0] | json_query(jmesquery) }}
use the map filter to apply that same filter to every list item, with something like {{ A.stdout_lines | map("json_query", jmesquery) | list }}
rewrite your JMESPath to apply that filter to the input list, akin to json_query("[*].configuration.AND THE REST HERE")
Those last two will naturally produce a different output shape, since they are lists of lists, and so it will look like [['ge-0/0/0']] when output, but they do have the advantage that if your stdout_lines ever does mysteriously start to contain more objects, they will be json_query-ied as expected