feat: add envSuffix tag to use environment variable with prefix

configor_test.go

@@ -33,6 +33,7 @@ type testConfig struct {
 		Name  string
 		Email string `required:"true"`
 	}
+	MetaInfo string `envSuffix:"META_INFO"`
 
 	Anonymous `anonymous:"true"`
 
@@ -65,6 +66,7 @@ func generateDefaultConfig() testConfig {
 				Email: "wosmvp@gmail.com",
 			},
 		},
+		MetaInfo: "defaultMetaInfo",
 		Anonymous: Anonymous{
 			Description: "This is an anonymous embedded struct whose environment variables should NOT include 'ANONYMOUS'",
 		},
@@ -562,6 +564,28 @@ func TestReadFromEnvironmentWithSpecifiedEnvName(t *testing.T) {
 	}
 }
 
+func TestReadFromEnvironmentWithSpecifiedEnvSuffixName(t *testing.T) {
+	config := generateDefaultConfig()
+
+	if bytes, err := json.Marshal(config); err == nil {
+		if file, err := ioutil.TempFile("/tmp", "configor"); err == nil {
+			defer file.Close()
+			defer os.Remove(file.Name())
+			file.Write(bytes)
+			var result testConfig
+			os.Setenv("CONFIGOR_META_INFO", "env_meta_info")
+			defer os.Setenv("CONFIGOR_META_INFO", "")
+			Load(&result, file.Name())
+
+			var defaultConfig = generateDefaultConfig()
+			defaultConfig.MetaInfo = "env_meta_info"
+			if !reflect.DeepEqual(result, defaultConfig) {
+				t.Errorf("result should equal to original configuration")
+			}
+		}
+	}
+}
+
 func TestAnonymousStruct(t *testing.T) {
 	config := generateDefaultConfig()
 

utils.go

@@ -270,22 +270,32 @@ func (configor *Configor) processTags(config interface{}, prefixes ...string) er
 	configType := configValue.Type()
 	for i := 0; i < configType.NumField(); i++ {
 		var (
-			envNames    []string
-			fieldStruct = configType.Field(i)
-			field       = configValue.Field(i)
-			envName     = fieldStruct.Tag.Get("env") // read configuration from shell env
+			envNames      []string
+			fieldStruct   = configType.Field(i)
+			field         = configValue.Field(i)
+			envName       = fieldStruct.Tag.Get("env")        // read configuration from shell env
+			envSuffixName = fieldStruct.Tag.Get("envSuffix") // read configuration from shell env
 		)
 
 		if !field.CanAddr() || !field.CanInterface() {
 			continue
 		}
 
-		if envName == "" {
-			envNames = append(envNames, strings.Join(append(prefixes, fieldStruct.Name), "_"))                  // Configor_DB_Name
-			envNames = append(envNames, strings.ToUpper(strings.Join(append(prefixes, fieldStruct.Name), "_"))) // CONFIGOR_DB_NAME
-		} else {
-			envNames = []string{envName}
+		if envName != "" {
+			envNames = append(envNames, envName)
 		}
+		if envSuffixName != "" {
+			envNames = append(
+				envNames,
+				strings.Join(append(prefixes, envSuffixName), "_"),                  // Configor_DB_Name
+				strings.ToUpper(strings.Join(append(prefixes, envSuffixName), "_")), // CONFIGOR_DB_NAME
+			)
+		}
+		envNames = append(
+			envNames,
+			strings.Join(append(prefixes, fieldStruct.Name), "_"),
+			strings.ToUpper(strings.Join(append(prefixes, fieldStruct.Name), "_")),
+		)
 
 		if configor.Config.Verbose {
 			fmt.Printf("Trying to load struct `%v`'s field `%v` from env %v\n", configType.Name(), fieldStruct.Name, strings.Join(envNames, ", "))