Fixing yaml indentation with python

Question

I'm manipulating existing yaml file (CloudFormation template) and copying needed resources into a new file.

The thing is, I'm getting part of the resource in a new line - not according to the correct indentation.
It seems the 3rd line is not adhering to the indentation configuration.

I've checked Python modules: yaml-indent, ruamel.yaml config, yamlfix, pyymal and off course our AI friends.. but the issue persists.

How can I write it in a correct manner ?

Code snippet:

    with open(entrypath, 'r') as magic:
        yaml_object = yaml.load(magic, Loader=yaml.SafeLoader)
        # print(yaml_object['Resources'][rscItem])

        with open('{}_Restore.yaml'.format(resourcename), 'a+') as s:
            s.write('  {}:'.format(rscItem))
            s.write('\n')
            s.write('    {}'.format(yaml.safe_dump(yaml_object['Resources'][rscItem], default_flow_style=False, indent=4)))

(I am aware of the spaces in s.write(' {}', that part is working as it should (-:)

Yaml file: How it looks like:

Resources:
  defaulteventbus:
    DeletionPolicy: Retain
Properties:
  Name: default
  Tags: []
Type: AWS::Events::EventBus
UpdateReplacePolicy: Retain

  LambdaEventSourceMapping:
    DeletionPolicy: Retain
Properties:
  BatchSize: 1
  BisectBatchOnFunctionError: true
  DestinationConfig:
    OnFailure:
      Destination:
        Ref: SNSTopicName
  Enabled: true

How it should looks like:

Resources:
  defaulteventbus:
    DeletionPolicy: Retain
    Properties:
      Name: default
      Tags: []
    Type: AWS::Events::EventBus
    UpdateReplacePolicy: Retain

  LambdaEventSourceMapping:
    DeletionPolicy: Retain
    Properties:
      BatchSize: 1
      BisectBatchOnFunctionError: true
      DestinationConfig:
        OnFailure:
          Destination:
            Ref: SNSTopicName
      Enabled: true

Updated code that @Michael wrote:

    with open(entrypath, 'r') as magic:
            yaml_object = yaml.load(magic, Loader=yaml.SafeLoader)
            # print(yaml_object['Resources'][rscItem])

    with open('{}_Restore.yaml'.format(resourcename), 'a+') as s:
            data = {rscItem: yaml_object['Resources'][rscItem]}
            text = yaml.safe_dump(data, default_flow_style=False, indent=2)
            s.write(textwrap.indent(text, ' ' * 2))

Answer 1

The question is not totally clear, but maybe this will help:

import textwrap
import yaml

with open('source.yaml', 'r') as magic:
    source = yaml.load(magic, Loader=yaml.SafeLoader)
    for rscItem in source['Resources'].keys():
        with open('{}_Restore.yaml'.format(rscItem), 'a+') as s:
            data = {rscItem: source['Resources'][rscItem]}
            text = yaml.safe_dump(data, default_flow_style=False, indent=4)
            s.write(textwrap.indent(text, ' ' * 4)

Assuming you have input file source.yaml

Resources:
  defaulteventbus:
    DeletionPolicy: Retain
    Properties:
      Name: default
      Tags: []
    Type: AWS::Events::EventBus
    UpdateReplacePolicy: Retain

  LambdaEventSourceMapping:
    DeletionPolicy: Retain
    Properties:
      BatchSize: 1
      BisectBatchOnFunctionError: true
      DestinationConfig:
        OnFailure:
          Destination:
            Ref: SNSTopicName
      Enabled: true

the script above outputs files

    defaulteventbus:
        DeletionPolicy: Retain
        Properties:
            Name: default
            Tags: []
        Type: AWS::Events::EventBus
        UpdateReplacePolicy: Retain

and

    LambdaEventSourceMapping:
        DeletionPolicy: Retain
        Properties:
            BatchSize: 1
            BisectBatchOnFunctionError: true
            DestinationConfig:
                OnFailure:
                    Destination:
                        Ref: SNSTopicName
            Enabled: true