ansible、jinja2、json - 在 Jinja 中使用 json_query？

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!

Answer 1

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 + '`]')