Using jq to append output generated from Ansible template - json

Question

I am writing Ansible play, one of the tasks is to append entry to a JSON document. E.g.
JSON document staff.json:
{
"staff":[
{
"john":[
{
"position":"techwriter"
},
{
"sex":"male"
}
]
}
]
}
I need to append this entry to staff:
{
"staff":[
{
"john":[
{
"position":"techwriter"
},
{
"sex":"male"
}
]
},
{
"jane":[
{
"position":"admin"
},
{
"sex":"female"
}
]
}
]
}
The entry would be generated from Ansible template, something like this:
{
"{{ staff_name }}":[
{
"position":"{{ staff_position }}"
},
{
"sex":"{{ staff_sex }}"
}
]
}
I've learned to use jq to append entry to the JSON document, as seen in "Add json array element with jq (cmdline)". However, I do not know how I can implement this in Ansible, as template would output to a file.
I need a solution of something like this:
cat staff.json | jq '.staff |= .+ ["OUTPUT_FROM_TEMPLATE"]'
Any ideas welcome.

Answer 1

You may use template lookup plugin:
- shell: cat staff.json | jq '.staff |= . + [{{ item | to_json }}]' > staff.json
with_template: person.j2
vars:
staff_name: jane
staff_position: admin
staff_sex: female
Note that you need to use to_json filter with item, because Ansible template engine converts json strings that it can evaluate into dict.