JSON Merge Patch

External

• https://datatracker.ietf.org/doc/html/rfc7386
• https://kubernetes.io/docs/tasks/manage-kubernetes-objects/update-api-object-kubectl-patch/
• https://erosb.github.io/post/json-patch-vs-merge-patch/

Internal

• kubectl patch
• JSON Patch

Overview

JSON merge patch is defined by RFC7386.

JSON merge patch defines a JSON document format appropriate for modifying a target JSON document. The format is suitable to use with the HTTP PATCH method and an "application/merge-patch+json" media type.

PATCH /target HTTP/1.1
Host: example.org
Content-Type: application/merge-patch+json

{
  "a":"z",
  "c": {
 "f": null
   }
}

Behavior on Arrays

Arrays cannot be manipulated by merge patches. If you want to add an element to an array, or mutate any of its elements then you have to include the entire array in the merge patch document, even if the actually changed parts is minimal. The new list completely replaces the existing list.

Also See

JSON Patch

Kubernetes Strategic Merge Patch