k8s源码设计模式之Builder

发表于
Builder模式也叫生成器模式，也叫建造者模式

关于生成器模式详情可查看文章

记录下k8s源码中使用到的Builder模式。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
// staging/src/k8s.io/client-go/rest/request.go
// Request 构建一个请求发送给kube-apiserver.
// 其中有很多元素需要设置，但只一些是必须的
type Request struct {
	c *RESTClient

	warningHandler WarningHandler

	rateLimiter flowcontrol.RateLimiter
	backoff     BackoffManager
	timeout     time.Duration
	maxRetries  int

	// generic components accessible via method setters
	verb       string
	pathPrefix string
	subpath    string
	params     url.Values
	headers    http.Header

	// structural elements of the request that are part of the Kubernetes API conventions
	namespace    string
	namespaceSet bool
	resource     string
	resourceName string
	subresource  string

	// output
	err error

	// only one of body / bodyBytes may be set. requests using body are not retriable.
	body      io.Reader
	bodyBytes []byte

	retryFn requestRetryFunc
}

// NewRequest 方法创建一个Request结构体并返回指针
func NewRequest(c *RESTClient) *Request {
    ...
	r := &Request{
		c:              c,
		rateLimiter:    c.rateLimiter,
		backoff:        backoff,
		timeout:        timeout,
		pathPrefix:     pathPrefix,
		maxRetries:     10,
		retryFn:        defaultRequestRetryFn,
		warningHandler: c.warningHandler,
	}
    ...
	return r
}


func (r *Request) Verb(verb string) *Request {
	r.verb = verb
	return r
}


func (r *Request) Prefix(segments ...string) *Request {
	if r.err != nil {
		return r
	}
	r.pathPrefix = path.Join(r.pathPrefix, path.Join(segments...))
	return r
}


func (r *Request) Suffix(segments ...string) *Request {
	if r.err != nil {
		return r
	}
	r.subpath = path.Join(r.subpath, path.Join(segments...))
	return r
}
使用示例
1
2
r := NewRequest(clientSet)
r.Verb("Post").Prefix("apps")

REF:
1.client-go/rest/request.go