其他RESTMapper

之前的两次关于RESTMapper的分析都是和DefaultRESTMapper相关的。除了DefaultRESTMapper以外，Kubernetes还实现了PriorityRESTMapper，MuiltiRESTMaper和FirstHitRESTMapper。本次分析就来看下这些RESTMapper的实现。

PriorityRESTMapper

PriorityRESTMapper定义在/pkg/api/meta/priority.go中：

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// PriorityRESTMapper is a wrapper for automatically choosing a particular Resource or Kind
// when multiple matches are possible
type PriorityRESTMapper struct {
	// Delegate is the RESTMapper to use to locate all the Kind and Resource matches
	Delegate RESTMapper
	// ResourcePriority is a list of priority patterns to apply to matching resources.
	// The list of all matching resources is narrowed based on the patterns until only one remains.
	// A pattern with no matches is skipped.  A pattern with more than one match uses its
	// matches as the list to continue matching against.
	ResourcePriority []unversioned.GroupVersionResource
	// KindPriority is a list of priority patterns to apply to matching kinds.
	// The list of all matching kinds is narrowed based on the patterns until only one remains.
	// A pattern with no matches is skipped.  A pattern with more than one match uses its
	// matches as the list to continue matching against.
	KindPriority []unversioned.GroupVersionKind
}

PriorityRESTMapper封装了一个RESTMapper，及ResourcePriority和KindPriority。与DefaultRESTMapper多值处理方式(出错处理)不同的是，PriorityRESTMapper会依据ResourcePriority和KindPriority对多值进行过滤，直到只有一个结果为止。
具体PriorityRESTMapper方法这里就不再详细分析。

MultiRESTMapper

MultiRESTMapper定义在/pkg/api/meta/multirestmapper.go中：

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type MultiRESTMapper []RESTMapper

MultiRESTMapper中封装了多个RESTMapper，对于KindsFor()，ResourcesFor()，RESTMappings()，MultiRESTMapper会收集所有RESTMapper的结果；对于KindFor()，ResourceFor()，RESTMapping()的多值处理方式和DefaultRESTMapper相同，直接出错处理。
具体MultiRESTMapper方法这里就不再详细分析。

FirstHitRESTMapper

FirstHitRESTMapper定义在/pkg/api/meta/firsthit_restmapper.go中：

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type FirstHitRESTMapper struct {
	MultiRESTMapper
}

FirstHitRESTMapper本质也封装了多个RESTMapper。与其他RESTMapper不同的是，FirstHitRESTMapper并没有实现KindsFor()，ResourcesFor()，RESTMappings()。从”FirstHitRESTMapper”这名字来看，也可以理解FirstHitRESTMapper的处理方式：当有一个RESTMapper成功，则直接返回。如KindFor()方法：

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func (m FirstHitRESTMapper) KindFor(resource unversioned.GroupVersionResource) (unversioned.GroupVersionKind, error) {
	errors := []error{}
	//***如果有一个RESTMapper符合，则立即返回***//
	for _, t := range m.MultiRESTMapper {
		ret, err := t.KindFor(resource)
		if err == nil {
			return ret, nil
		}
		errors = append(errors, err)
	}
	return unversioned.GroupVersionKind{}, collapseAggregateErrors(errors)
}

具体FirstHitRESTMapper其他方法这里就不再详细分析。

至此，RESTMapper分析完毕。