Transforming JSON array

Question

I need to conditionally transform a list of objects defined in a JSON file. The problem with the playbook is that I need the transformation to yield either the value of docker.network or id. Simply put, I need to figure out some kind of ternary operator for transforming lists. The playbook results in:

"msg": "['baz', AnsibleUndefined]"

I need

"msg": "['baz', 'bar']"

Playbook:

vars:
  daemons: "{{ lookup('file','./test.json') | from_json }}"

  tasks:
    - name: Transform
      debug:
        msg: "{{ daemons | map(attribute='docker.network')  }}"

test.json:

[
  {
    "id": "foo",
    "docker": {
      "network": "baz"
    }
  },
  {
    "id": "bar",
    "docker": {
    }
  }
]

Vladimir Botka · Accepted Answer · 2021-06-17 13:12:06Z

3

For example

    - debug:
        msg: "{{ _list }}"
      vars:
        _list: "{{ _list_str|from_yaml }}"
        _list_str: |
          [
          {% for i in daemons %}
          {% if i.docker.network is defined %}
          {{ i.docker.network }},
          {% else %}
          {{ i.id }},
          {% endif %}
          {% endfor %}
          ]

gives

  msg:
  - baz
  - bar

edited Jun 17, 2021 at 13:12

answered Jun 17, 2021 at 11:26

Vladimir Botka

69.9k7 gold badges45 silver badges78 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Daniel · Accepted Answer · 2021-06-17 08:22:32Z

1

You should process your file test.json for example using jq

jq 'map(. |= if .docker.network then . else . + {"docker":{"network": .id}} end)' test.json

will print

[
  {
    "id": "foo",
    "docker": {
      "network": "baz"
    }
  },
  {
    "id": "bar",
    "docker": {
      "network": "bar"
    }
  }
]

You can read more in pages:

https://kaijento.github.io/2017/03/26/json-parsing-jq-simplifying-with-map/ https://stedolan.github.io/jq/manual/#Math Add new element to existing JSON array with jq

And test your command on page:

https://jqplay.org/

answered Jun 17, 2021 at 8:22

Daniel

8,7757 gold badges63 silver badges88 bronze badges

2 Comments

Oliver Weichhold Over a year ago

test.json is the input data not the expect result. The result should only consist of the value of either docker.network or id.

Daniel Over a year ago

So you can use jq to transform streams not files. ( with linux pilelines )

Collectives™ on Stack Overflow

Transforming JSON array

2 Answers 2

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related