mergo.md

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• mergo
  • 应用

mergo

mergo可以在相同的结构体或map之间赋值，可以将结构体的字段赋值到map中，可以将map的值赋值给结构体的字段

应用

在 kubernates 中应用

// /Users/python/Downloads/git_download/kubernetes-master/staging/src/k8s.io/client-go/tools/clientcmd/loader.go

// Load starts by running the MigrationRules and then
// takes the loading rules and returns a Config object based on following rules.
//
//	if the ExplicitPath, return the unmerged explicit file
//	Otherwise, return a merged config based on the Precedence slice
//
// A missing ExplicitPath file produces an error. Empty filenames or other missing files are ignored.
// Read errors or files with non-deserializable content produce errors.
// The first file to set a particular map key wins and map key's value is never changed.
// BUT, if you set a struct value that is NOT contained inside of map, the value WILL be changed.
// This results in some odd looking logic to merge in one direction, merge in the other, and then merge the two.
// It also means that if two files specify a "red-user", only values from the first file's red-user are used.  Even
// non-conflicting entries from the second file's "red-user" are discarded.
// Relative paths inside of the .kubeconfig files are resolved against the .kubeconfig file's parent folder
// and only absolute file paths are returned.
func (rules *ClientConfigLoadingRules) Load() (*clientcmdapi.Config, error) {
	if err := rules.Migrate(); err != nil {
		return nil, err
	}

	errlist := []error{}
	missingList := []string{}

	kubeConfigFiles := []string{}

    // 。。。。。

	// first merge all of our maps
	mapConfig := clientcmdapi.NewConfig()

	for _, kubeconfig := range kubeconfigs {
		mergo.Merge(mapConfig, kubeconfig, mergo.WithOverride)
	}

	// merge all of the struct values in the reverse order so that priority is given correctly
	// errors are not added to the list the second time
	nonMapConfig := clientcmdapi.NewConfig()
	for i := len(kubeconfigs) - 1; i >= 0; i-- {
		kubeconfig := kubeconfigs[i]
		mergo.Merge(nonMapConfig, kubeconfig, mergo.WithOverride)
	}

	// since values are overwritten, but maps values are not, we can merge the non-map config on top of the map config and
	// get the values we expect.
	config := clientcmdapi.NewConfig()
	mergo.Merge(config, mapConfig, mergo.WithOverride)
	mergo.Merge(config, nonMapConfig, mergo.WithOverride)

	if rules.ResolvePaths() {
		if err := ResolveLocalPaths(config); err != nil {
			errlist = append(errlist, err)
		}
	}
	return config, utilerrors.NewAggregate(errlist)
}