Cannot filter with from_json

[Jerome Meyer]

Hi Team,

I'm encountered some issue with set_facts from variable with json and for this reason I'm tried to understand this. To reproduce this case I'm using the example from here : playbooks filters

tasks
  - shell: cat /some/path/to/file.json
    register: result

  - set_fact:
      myvar: "{{ result.stdout | from_json }}"

I've created one example.fson file :

# cat files/example.json
json_example: |
  {
      "example_simple": {
          "name": "simple",
          "foo": "value",
          "item": "this"
      },
  }

Here's the task file :

# cat tasks/main.yml
---
- name: Read JSON file
  shell: cat ../files/example.json
  register: json
 
- name: Get simple value.
  set_fact:
    simple_value: "{{ (json.stdout | from_json).example_simple.name }}"


- name: Simple debug.
  debug:
    msg: "{{ simple_value }}"

And here the result:

fatal: [localhost]: FAILED! => {"msg": "the field 'args' has an invalid value ({u'simple_value': u'{{ (json.stdout | from_json) }}'}), and could not be converted to an dict.The error was: No JSON object could be decoded\n\nThe error appears to be in '/etc/ansible/roles/testrole/tasks/main.yml': line 7, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- name: Get simple value.\n  ^ here\n"}

It tells me that the input cannot be converted to dict, But why and what is the problem? Could someone explain me this problem?

I cannot understand what is wrong.

Best regards, J

[Kai Stian Olstad]

On Tue, Feb 18, 2020 at 04:39:27AM -0800, Jerome Meyer wrote:
> Hi Team,
>
> I'm encountered some issue with set_facts from variable with json and for
> this reason I'm tried to understand this. To reproduce this case I'm using
> the example from here : playbooks filters

> <https://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html#filters-for-formatting-data>

>
> tasks
> - shell: cat /some/path/to/file.json
> register: result
>
> - set_fact:
> myvar: "{{ result.stdout | from_json }}"
>
>
> I've created one example.fson file :
> # cat files/example.json
> json_example: |
> {
> "example_simple": {
> "name": "simple",
> "foo": "value",
> "item": "this"
> },
> }

This is not correct json syntax.
It looks like yaml json_example multiline with an incorrectly syntax json in
it.


--
Kai Stian Olstad

[Dick Visser]

On Tue, 18 Feb 2020 at 13:39, Jerome Meyer <jer.m...@gmail.com> wrote:

Hi Team,

I'm encountered some issue with set_facts from variable with json and for this reason I'm tried to understand this. To reproduce this case I'm using the example from here : playbooks filters

tasks
  - shell: cat /some/path/to/file.json
    register: result

  - set_fact:
      myvar: "{{ result.stdout | from_json }}"

This here below looks like your example.json file actually contains yaml which in turn contains json?

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[Angel Rengifo Cancino]

Hello:

On Tue, Feb 18, 2020 at 7:39 AM Jerome Meyer <jer.m...@gmail.com> wrote:

I've created one example.fson file :

# cat files/example.json
json_example: |
  {
      "example_simple": {
          "name": "simple",
          "foo": "value",
          "item": "this"
      },
  }

Your JSON has an incorrect syntax. This is how should look like:

{

    "json_example": {
        "example_simple": {
            "name": "simple",
            "foo": "value",
            "item": "this"
        }
    }
}

This way, your playbook just runs fine:

    - shell: cat example.json

      register: result

    - set_fact:
        myvar: "{{ result.stdout | from_json }}"
   

    - debug: var=myvar

which produces this output:

TASK [shell] ************************************************************************************************************************************************************
changed: [localhost]

TASK [set_fact] *********************************************************************************************************************************************************
ok: [localhost]

TASK [debug] ************************************************************************************************************************************************************
ok: [localhost] => {
    "myvar": {
        "json_example": {
            "example_simple": {

                "foo": "value",
                "item": "this",

                "name": "simple"
            }
        }
    }
}

You can use this to parse your JSON files:

$ python -m json.tool < example.json

As Dick Visser said, it seems you're mixed some kind of YAML+JSON content which invalidates it at all

[Jerome Meyer]

Thank you all for your help and support.

Yes, now it's work.

@Angel: I'm really newbie in this kind of scripting and I do mix it up a little bit with these format.

If you have a clever tutorial, I want it  ;)

Regards, J

On Wednesday, February 19, 2020 at 1:20:18 AM UTC+1, Angel Rengifo Cancino wrote:

Hello:

[Angel Rengifo Cancino]

On Wed, Feb 19, 2020 at 4:38 AM Jerome Meyer <jer.m...@gmail.com> wrote:

Thank you all for your help and support.

Yes, now it's work.

@Angel: I'm really newbie in this kind of scripting and I do mix it up a little bit with these format.

If you have a clever tutorial, I want it  ;)

Sorry, I don't have a tutorial for that. I'm planning to do one, in a near future.

I also suffered a little bit with JSON and its structures, because I didn't have clear concepts of objects and arrays. Just practice made the difference for me :)

[Jerome Meyer]

On Wednesday, February 19, 2020 at 1:15:17 PM UTC+1, Angel Rengifo Cancino wrote:

Ok, yes the practical way is the best but the harder... ;)