patch

Overview ¶

Package patch implements a simple patching mechanism for k8s resources. Paths are specified in the form a.b.c.[key:value].d.[list_entry_value], where:

• [key:value] selects a list entry in list c which contains an entry with key:value
• [list_entry_value] selects a list entry in list d which is a regex match of list_entry_value.

Some examples are given below. Given a resource:

kind: Deployment metadata:

name: istio-citadel
namespace: istio-system

a:

b:
- name: n1
  value: v1
- name: n2
  list:
  - "vv1"
  - vv2=foo

values and list entries can be added, modifed or deleted.

MODIFY ¶

1. set v1 to v1new

path: a.b.[name:n1].value
value: v1

2. set vv1 to vv3

// Note the lack of quotes around vv1 (see NOTES below).
path: a.b.[name:n2].list.[vv1]
value: vv3

3. set vv2=foo to vv2=bar (using regex match)

path: a.b.[name:n2].list.[vv2]
value: vv2=bar

DELETE ¶

1. Delete container with name: n1

path: a.b.[name:n1]

2. Delete list value vv1

path: a.b.[name:n2].list.[vv1]

ADD ¶

1. Add vv3 to list

path: a.b.[name:n2].list
value: vv3

2. Add new key:value to container name: n1

path: a.b.[name:n1]
value:
  new_attr: v3

*NOTES* - Due to loss of string quoting during unmarshaling, keys and values should not be string quoted, even if they appear that way in the object being patched. - [key:value] treats ':' as a special separator character. Any ':' in the key or value string must be escaped as \:.