yaml-patch 0.1.1

Patch yaml strings

yaml-patch

Apply patches to a yaml string, keeping most of the formatting and comments.

Some formatting is not kept due to underlying yaml library limitations:

• Indentation will be forced to two spaces
• Spacing before sequence dashes will be forced to two spaces
• Empty lines at the start of the string will be removed

As a command line tool

You can pass any number of patches to be applied, they use the following syntax options:

Patch a single value:

<field>.<subfield>=<value>

Example:

yaml-patch -f test.yml  'spec.replicas=2'

Patch a value inside a single list item:

<field>.[<position]>.<subfield>=<value>

Example:

yaml-patch -f test.yml  'spec.template.containers.[0].image="mycontainer:latest"'

Patch a value inside all list items:

<field>.[].<subfield>=<value>

Example:

yaml-patch -f test.yml 'spec.template.containers.[].image="mycontainer:latest"'

As a Python library

To use yaml-patch as a library just import the function and pass patches as dictionary entries.

Example:

from yaml_patch import patch
from textwrap import dedent

def override_list_all_values():
    source_yaml = dedent(
        """\
        some_list:
          - alice
          - bob
        """
    )
    patches = {"some_list.[]": "charlie"}
    expected_yaml = dedent(
        """\
        some_list:
          - charlie
          - charlie
        """
    )
    assert patch(source_yaml, patches) == expected_yaml