ansible, jinja2, json - Using json_query in Jinja?

Question

Hello Developer Community!

I'm currently working on developing some Ansible playbooks to manage Citrix NetScaler configuration and would like to get some help about the following. I have the following data structure defined in a variable file:

nsadc_config_file_textfsm_nsapp_lb_service_parsed

    {
    "bind_lbvserver_NotParsed": "",
    "bind_lbvserver_analyticsprofile": "",
    "bind_lbvserver_gotopriorityexpression": "",
    "bind_lbvserver_name": "VSRV-CS-Client1",
    "bind_lbvserver_policyname": "",
    "bind_lbvserver_priority": "",
    "bind_lbvserver_service_group_name": "SVC_Client1_App1_Server1_Port1",
    "bind_lbvserver_type": "",
    "bind_lbvserver_weight": ""
},
{
    "bind_lbvserver_NotParsed": "",
    "bind_lbvserver_analyticsprofile": "",
    "bind_lbvserver_gotopriorityexpression": "NEXT",
    "bind_lbvserver_name": "VSRV_Client2_App2",
    "bind_lbvserver_policyname": "policy_Client2_Rewrite",
    "bind_lbvserver_priority": "80",
    "bind_lbvserver_service_group_name": "",
    "bind_lbvserver_type": "REQUEST",
    "bind_lbvserver_weight": ""
},

I would like to query this JSON structure in a Jinja file, tried the followings but unfortunately it does not work. I'm not 100% sure if it is possible to use "json_query" in a Jinja file.

                                servicebindings:
{% for item_1 in nsadc_config_file_textfsm_nsapp_lb_vserver_binding_parsed %}
{% if (item_0.add_lbvserver_name == item_1.bind_lbvserver_name) and (item_1.bind_lbvserver_service_group_name in nsadc_config_file_textfsm_nsapp_lb_service_parsed) %}

                                    - servicename:         "{{ item_1.bind_lbvserver_service_group_name }}"
{% if item_1.bind_lbvserver_weight is defined and item_1.bind_lbvserver_weight %}
                                      weight:              "{{ item_1.bind_lbvserver_weight }}"
{% endif %}
{% endif %}
{% endfor %}

Instead of using (item_1.bind_lbvserver_service_group_name in nsadc_config_file_textfsm_nsapp_lb_service_parsed) above, I have also tried to include a json_query statement directly in Jinja, but with no luck. I'm afraid, there might be an issue with using quotes and escape chars.

{% if (item_0.add_lbvserver_name == item_1.bind_lbvserver_name) and (nsadc_config_file_textfsm_nsapp_lb_service_parsed | json_query(\"[?add_svc_name == '\" + item_1.bind_lbvserver_service_group_name + \"']\")) %}

Could anybody please advise if it is possible to query JSON structure directly in Jinja?

Many thanks in advance!

Yes, you're over-escaping quotes, but it's hard to test out a correction. You're searching `nsadc_config_file_textfsm_nsapp_lb_service_parsed` for an attribute named `add_svc_name`, but your sample data shows no such attribute. You're referring to a variable named `nsadc_config_file_textfsm_nsapp_lb_vserver_binding_parsed` but we have no idea what that looks like. — larsks, Nov 10 '20 at 12:26

score 0 · Accepted Answer · answered Nov 10 '20 at 13:04

json_query is a Jinja filter, so of course you can use it in a template...or anywhere else that Jinja expressions are valid.

For example, if I have data in a playbook like this (and a template task):

- hosts: localhost
  gather_facts: false
  vars:
    var1:
      - name: thing1
        color: red
      - name: thing2
        color: blue

    var2:
      - name: bob
        likes: blue
      - name: alice
        likes: green

  tasks:
    - template:
        src: template.in
        dest: output.txt

I can write a template that looks like this:

{% for person in var2 %}
{% for thing in var1|json_query('[?color == `{}`]'.format(person.likes)) %}
- {{ person.name }} likes {{ thing.name }}
{% endfor %}
{% endfor %}

Which will produce the following output in output.txt:

- bob likes thing2

Note two things about the json_query expression in the template:

Because we're looking for a literal string, we need to use backticks to quote the value.
We're using Python string formatting to include our target value in the query string.

In lieu of the string formatting syntax we could instead have written:

json_query('[?color == `' + person.likes + '`]')

Dear larsks! Thank You very much for Your help and support, it works like a charm :-) — Belabacsi, Nov 10 '20 at 21:32

ansible, jinja2, json - Using json_query in Jinja?

1 Answers1