I have been trying to update the values in a dictionary in destination json with the values in the dictionary in source JSON file. Below is the example of source and destination JSON file:

Source file:

[
        {
                "key": "MYSQL",
                "value": "456"
        },
        {
                "key": "RDS",
                "value": "123"
        }
]

Destination File:

[
        {
                "key": "MYSQL",
                "value": "100"
        },
        {
                "key": "RDS",
                "value": "111"
        }
        {
                "key": "DB1",
                "value": "TestDB"
        },
        {
                "key": "OS",
                "value": "EX1"
        }
]

Expectation in destination file after running Ansible playbook:

[
        {
                "key": "MYSQL",
                "value": "**456**"
        },
        {
                "key": "RDS",
                "value": "**123**"
        }
        {
                "key": "DB1",
                "value": "TestDB"
        },
        {
                "key": "OS",
                "value": "EX1"
        }
]

Below is the playbook I have tried so far, but this only updates the value if it is hard coded:

- hosts: localhost
  tasks:

  - name: Parse JSON
    shell: cat Source.json
    register: result

  - name: Save json data to a variable
    set_fact:
      jsondata: "{{result.stdout | from_json}}"

  - name: Get key names
    set_fact:
      json_key: "{{ jsondata | map(attribute='key') | flatten }}"

  - name: Get Values names
    set_fact:
      json_value: "{{ jsondata | map(attribute='value') | flatten }}"

  # Trying to update the destination file with only the values provided in source.json
  - name: Replace values in json
    replace:
      path: Destination.json
      regexp: '"{{ item }}": "100"'
      replace: '"{{ item }}": "456"'
    loop:
    - value

The main goal is to update the value in destination.json with the value provided in source.json.

CodePudding user response：

Without to knowing the structure of your destination file it's difficult to use a regex.
I suggest you to load your destination file in a variable, do the changes and save the content of variable to file.

This solution does the job:

- hosts: localhost
  tasks:

    - name: Parse JSON
      set_fact:
        result: [ { "key": "MYSQL", "value": "456" }, { "key": "RDS", "value": "123" } ]

    - name: Parse JSON
      set_fact:
        json_old: [ { "key": "MYSQL", "value": "100" }, { "key": "RDS", "value": "111" }, { "key": "DB1", "value": "TestDB" }, { "key": "OS", "value": "EX1" } ]

    - name: create new json
      set_fact:
        json_new: "{{ json_new | d([])   ([item] if _rec == [] else [_rec]) | flatten }}"
      loop: "{{ json_old }}"
      vars:
        _rec: "{{ result | selectattr('key', 'equalto', item.key) }}"


    - name: display json_new
      debug:
        msg: "{{ json_new }}"

Result:

ok: [localhost] => {
    "msg": [
        {
            "key": "MYSQL",
            "value": "456"
        },
        {
            "key": "RDS",
            "value": "123"
        },
        {
            "key": "DB1",
            "value": "TestDB"
        },
        {
            "key": "OS",
            "value": "EX1"
        }
    ]
}

You could use your_json_feed: "{{ lookup('file', 'path') | from_json }}" to load a JSON file into variable.

And to save: - copy: content="{{ your_json_feed }}" dest=/path/to/destination/file.

CodePudding user response：

In Ansible, the couple key/value tends to be handled with the filters dict2items and items2dict. And your use case can be handled by those filters.

Here would be the logic:

• Read both files
• Convert both files into dictionaries, with dict2items
• Combine the two dictionaries, with the combine filter
• Convert the dictionary back into a list with items2dict
• Dump the result as in JSON back into the file

Given the playbook:

- hosts: localhost
  gather_facts: no

  tasks:
    - shell: cat Source.json
      register: source

    - shell: cat Destination.json
      register: destination

    - copy:
        content: >- 
          {{ 
            destination.stdout | from_json | items2dict | 
            combine(
              source.stdout | from_json | items2dict
            ) | dict2items | to_nice_json
          }}
        dest: Destination.json

We end up with Destination.json containing:

[{"key": "MYSQL", "value": "456"}, {"key": "RDS", "value": "123"}, {"key": "DB1", "value": "TestDB"}, {"key": "OS", "value": "EX1"}]