Very new to JSON.
I'm trying to extract 2 variables from this json file.
It has many files and id's but I only want the file & id if it contains es7.x86_64
When done my desired variables would be:
id=13140
file=NessusAgent-8.3.0-es7.x86_64.rpm
{
"banners": [],
"containsRequiredAuth": true,
"created_at": "2017-10-13T00:53:32.137Z",
"description": "Download Nessus Agents for use with Tenable.io and Nessus Manager",
"documentation_link": null,
"downloads": [
{
"created_at": "2021-06-29T19:06:41.776Z",
"description": "Red Hat ES 7 (64-bit) / CentOS 7 / Oracle Linux 7 (including Unbreakable Enterprise Kernel)",
"file": "NessusAgent-8.3.0-es7.x86_64.rpm",
"id": 13140,
"meta_data": {
"md5": "f67a2bdd2a7180f66b75f319439d56d5",
"product": "Nessus Agents - 8.3.0",
"product_notes": null,
"product_release_date": "06/29/2021",
"product_type": "default",
"release_date": "06/03/2021",
"sha256": "8a6452086ce0a7193e0f24b1f2adbff3aa6bd0f4ac519384e8453bb68bae0460",
"version": "8.3.0"
},
"name": "NessusAgent-8.3.0-es7.x86_64.rpm",
"page_id": 61,
"publish": true,
"required_auth": false,
"size": 16375828,
"sort_order": null,
"type": "download",
"updated_at": "2021-06-29T19:08:47.628Z"
},
My utterly failed attempt to assign file & id variables that have es7.x86_64.
- name: Convert agent_tempfile to json and register result
shell: python -m json.tool "{{ agent_tempfile }}"
register: result
- name: Extract file & id for es7.x86_64 rpm's
set_fact:
agent_id: "{{ result | json_query('downloads[*es7.x86_64*].id') | first }}"
agent_file: "{{ result | json_query('downloads[*es7.x86_64*].file') | first }}"
I have a feeling I'm going to be doing a lot more of these types of queries soon. Can some one also direct me to a good guide that details parsing specific values from JSON output? The stuff I've found so far just lists arrays but I really want to know how to pull specific data out.
First, there are some great tools out there for playing with JMESPath syntax (the syntax used by the json_query filter). The examples in the JMESPath tutorial are all "live": you can paste your own data into the text fields, and then experiment with filters and check the result.
The jpterm command is a terminal tool for experimenting with JMESPath queries. This is my personal favorite.
To look for items that contain a specific substring (like es7.x86_64), you can use the contains operator, like this:
json_query("downloads[?contains(name, 'es7.x86_64')]")
To make this work for your code, we first need to deal with the fact
that the result of your first task is going to be a string, rather
than a dictionary. We'll need to pass the standard output through the
from_json filter.
We can also avoid having two almost identical json_query expression
by moving the bulk of the expression into a task-local variable.
This gives us something like:
- hosts: localhost
gather_facts: false
tasks:
- command: cat data.json
register: result
- set_fact:
agent_id: "{{ selected[0].id }}"
agent_file: "{{ selected[0].file }}"
vars:
selected: >-
{{
result.stdout |
from_json |
json_query("downloads[?contains(name, 'es7.x86_64')]")
}}
- debug:
msg:
- "ID: {{ agent_id }}"
- "FILE: {{ agent_file }}"
When that task runs, the value of selected will be something like:
[
{
"file": "NessusAgent-8.3.0-es7.x86_64.rpm",
"id": 13140,
"name": "NessusAgent-8.3.0-es7.x86_64.rpm",
"page_id": 61,
"publish": true,
"required_auth": false,
"size": 16375828,
"sort_order": null,
"type": "download",
"updated_at": "2021-06-29T19:08:47.628Z"
}
]
This assumes you're only expecting a single result, so we can just ask
for selected[0] to get at that dictionary, and then it's a simple
matter of getting at the .id and .file attributes.
Running the above playbook produces:
TASK [debug] *********************************************************************************
ok: [localhost] => {
"msg": [
"ID: 13140",
"FILE: NessusAgent-8.3.0-es7.x86_64.rpm"
]
}