策略合并 patch

对于策略性合并 patch，列表可以根据其 patch 策略进行替换或合并。 patch 策略由 Kubernetes 源代码中字段标记中的 patchStrategy 键的值指定。 例如，PodSpec 结构体的 Containers 字段的 patchStrategy 为 merge：

  1. type PodSpec struct {
  2.   ...
  3.   Containers []Container `json:"containers" patchStrategy:"merge" patchMergeKey:"name" ...`

策略合并 patch 操作使用默认的 patch 策略，也就是 replace。

  1. type PodSpec struct {
  2.   ...
  3.   Tolerations []Toleration `json:"tolerations,omitempty" protobuf:"bytes,22,opt,name=tolerations"`

JSON 合并 patch

https://erosb.github.io/post/json-patch-vs-merge-patch/

As a quick example (taken from the spec) if we have the following document:

  1. {
  2.     "a": "b",
  3.     "c": {
  4.         "d": "e",
  5.         "f": "g"
  6.     }
  7. }

Then we can run the following patch on it:

  1. {
  2.     "a":"z",
  3.     "c": {
  4.         "f": null
  5.     }
  6. }

which will change the value of "a" to "z" and will delete the "f" key.

JSON patch

As a short example lets consider the following JSON document:

  1. {
  2.     "users" : [
  3.         { "name" : "Alice" , "email" : "alice@example.org" },
  4.         { "name" : "Bob" , "email" : "bob@example.org" }
  5.     ]
  6. }

We can run the following patch on it, which changes Alice’s email address then adds a new element to the array:

  1. [
  2.     {
  3.         "op" : "replace" ,
  4.         "path" : "/users/0/email" ,
  5.         "value" : "alice@wonderland.org"
  6.     },
  7.     {
  8.         "op" : "add" ,
  9.         "path" : "/users/-" ,
  10.         "value" : {
  11.             "name" : "Christine",
  12.             "email" : "christine@example.org"
  13.         }
  14.     }
  15. ]

The result will be:

  1. {
  2.     "users" : [
  3.         { "name" : "Alice" , "email" : "alice@wonderland.org" },
  4.         { "name" : "Bob" , "email" : "bob@example.org" },
  5.         { "name" : "Christine" , "email" : "christine@example.org" }
  6.     ]
  7. }