refactor: openpitrix module

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/koding/multiconfig/env.go

@@ -0,0 +1,129 @@
+package multiconfig
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/fatih/camelcase"
+	"github.com/fatih/structs"
+)
+
+// EnvironmentLoader satisifies the loader interface. It loads the
+// configuration from the environment variables in the form of
+// STRUCTNAME_FIELDNAME.
+type EnvironmentLoader struct {
+	// Prefix prepends given string to every environment variable
+	// {STRUCTNAME}_FIELDNAME will be {PREFIX}_FIELDNAME
+	Prefix string
+
+	// CamelCase adds a separator for field names in camelcase form. A
+	// fieldname of "AccessKey" would generate a environment name of
+	// "STRUCTNAME_ACCESSKEY". If CamelCase is enabled, the environment name
+	// will be generated in the form of "STRUCTNAME_ACCESS_KEY"
+	CamelCase bool
+}
+
+func (e *EnvironmentLoader) getPrefix(s *structs.Struct) string {
+	if e.Prefix != "" {
+		return e.Prefix
+	}
+
+	return s.Name()
+}
+
+// Load loads the source into the config defined by struct s
+func (e *EnvironmentLoader) Load(s interface{}) error {
+	strct := structs.New(s)
+	strctMap := strct.Map()
+	prefix := e.getPrefix(strct)
+
+	for key, val := range strctMap {
+		field := strct.Field(key)
+
+		if err := e.processField(prefix, field, key, val); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// processField gets leading name for the env variable and combines the current
+// field's name and generates environment variable names recursively
+func (e *EnvironmentLoader) processField(prefix string, field *structs.Field, name string, strctMap interface{}) error {
+	fieldName := e.generateFieldName(prefix, name)
+
+	switch strctMap.(type) {
+	case map[string]interface{}:
+		for key, val := range strctMap.(map[string]interface{}) {
+			field := field.Field(key)
+
+			if err := e.processField(fieldName, field, key, val); err != nil {
+				return err
+			}
+		}
+	default:
+		v := os.Getenv(fieldName)
+		if v == "" {
+			return nil
+		}
+
+		if err := fieldSet(field, v); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// PrintEnvs prints the generated environment variables to the std out.
+func (e *EnvironmentLoader) PrintEnvs(s interface{}) {
+	strct := structs.New(s)
+	strctMap := strct.Map()
+	prefix := e.getPrefix(strct)
+
+	keys := make([]string, 0, len(strctMap))
+	for key := range strctMap {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		field := strct.Field(key)
+		e.printField(prefix, field, key, strctMap[key])
+	}
+}
+
+// printField prints the field of the config struct for the flag.Usage
+func (e *EnvironmentLoader) printField(prefix string, field *structs.Field, name string, strctMap interface{}) {
+	fieldName := e.generateFieldName(prefix, name)
+
+	switch strctMap.(type) {
+	case map[string]interface{}:
+		smap := strctMap.(map[string]interface{})
+		keys := make([]string, 0, len(smap))
+		for key := range smap {
+			keys = append(keys, key)
+		}
+		sort.Strings(keys)
+		for _, key := range keys {
+			field := field.Field(key)
+			e.printField(fieldName, field, key, smap[key])
+		}
+	default:
+		fmt.Println("  ", fieldName)
+	}
+}
+
+// generateFieldName generates the field name combined with the prefix and the
+// struct's field name
+func (e *EnvironmentLoader) generateFieldName(prefix string, name string) string {
+	fieldName := strings.ToUpper(name)
+	if e.CamelCase {
+		fieldName = strings.ToUpper(strings.Join(camelcase.Split(name), "_"))
+	}
+
+	return strings.ToUpper(prefix) + "_" + fieldName
+}