add autonaming (#16)

aconfig.go

@@ -11,6 +11,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/BurntSushi/toml"
 	"gopkg.in/yaml.v2"
@@ -305,19 +306,11 @@ func (l *Loader) assertBuilt() {
 }
 
 func (l *Loader) getEnvName(field *fieldData) string {
-	name := field.name
-	if field.envName != "" {
-		name = field.envName
-	}
-	return strings.ToUpper(l.config.EnvPrefix + strings.ReplaceAll(name, ".", "_"))
+	return l.config.EnvPrefix + field.envName
 }
 
 func (l *Loader) getFlagName(field *fieldData) string {
-	name := field.name
-	if field.flagName != "" {
-		name = field.flagName
-	}
-	return strings.ToLower(l.config.FlagPrefix + name)
+	return l.config.FlagPrefix + field.flagName
 }
 
 func (l *Loader) setFieldData(field *fieldData, value string) error {
@@ -380,14 +373,16 @@ type fieldData struct {
 }
 
 func newFieldData(field reflect.StructField, value reflect.Value, parent *fieldData) *fieldData {
+	words := splitNameByWords(field.Name)
+
 	return &fieldData{
 		name:         makeName(field.Name, parent),
 		parent:       parent,
 		value:        value,
 		field:        field,
 		defaultValue: field.Tag.Get(defaultValueTag),
-		envName:      field.Tag.Get(envNameTag),
-		flagName:     field.Tag.Get(flagNameTag),
+		envName:      makeEnvName(field, parent, words),
+		flagName:     makeFlagName(field, parent, words),
 		usage:        field.Tag.Get(usageTag),
 	}
 }
@@ -403,6 +398,39 @@ func makeName(name string, parent *fieldData) string {
 	return parent.name + "." + name
 }
 
+func makeEnvName(field reflect.StructField, parent *fieldData, words []string) string {
+	envName := field.Tag.Get(envNameTag)
+	if envName == "" {
+		envName = makeParsingName(words)
+	}
+	if parent != nil {
+		envName = parent.envName + "_" + envName
+	}
+	return strings.ToUpper(envName)
+}
+
+func makeFlagName(field reflect.StructField, parent *fieldData, words []string) string {
+	flagName := field.Tag.Get(flagNameTag)
+	if flagName == "" {
+		flagName = makeParsingName(words)
+	}
+	if parent != nil {
+		flagName = parent.flagName + "." + flagName
+	}
+	return strings.ToLower(flagName)
+}
+
+func makeParsingName(words []string) string {
+	name := ""
+	for i, w := range words {
+		if i > 0 {
+			name += "_"
+		}
+		name += strings.ToLower(w)
+	}
+	return name
+}
+
 func (f *fieldData) Name() string {
 	return f.name
 }
@@ -560,3 +588,46 @@ func setMap(field *fieldData, value string) error {
 	field.value.Set(mapField)
 	return nil
 }
+
+// based on https://github.com/fatih/camelcase
+func splitNameByWords(src string) []string {
+	var runes [][]rune
+	lastClass, class := 0, 0
+
+	// split into fields based on class of unicode character
+	for _, r := range src {
+		switch true {
+		case unicode.IsLower(r):
+			class = 1
+		case unicode.IsUpper(r):
+			class = 2
+		case unicode.IsDigit(r):
+			class = 3
+		default:
+			class = 4
+		}
+		if class == lastClass {
+			runes[len(runes)-1] = append(runes[len(runes)-1], r)
+		} else {
+			runes = append(runes, []rune{r})
+		}
+		lastClass = class
+	}
+
+	// handle upper case -> lower case sequences, e.g.
+	// "PDFL", "oader" -> "PDF", "Loader"
+	for i := 0; i < len(runes)-1; i++ {
+		if unicode.IsUpper(runes[i][0]) && unicode.IsLower(runes[i+1][0]) {
+			runes[i+1] = append([]rune{runes[i][len(runes[i])-1]}, runes[i+1]...)
+			runes[i] = runes[i][:len(runes[i])-1]
+		}
+	}
+
+	words := []string{}
+	for _, s := range runes {
+		if len(s) > 0 {
+			words = append(words, string(s))
+		}
+	}
+	return words
+}

aconfig_test.go

@@ -221,17 +221,17 @@ func TestLoadFile_WithFiles(t *testing.T) {
 func TestLoadEnv(t *testing.T) {
 	setEnv(t, "TST_STR", "str-env")
 	setEnv(t, "TST_INT", "121")
-	setEnv(t, "TST_HTTPPORT", "3000")
+	setEnv(t, "TST_HTTP_PORT", "3000")
 	setEnv(t, "TST_SUB_FLOAT", "222.333")
-	setEnv(t, "TST_ANON_ISANON", "true")
+	setEnv(t, "TST_ANON_IS_ANON", "true")
 	setEnv(t, "TST_EM", "em-env")
 	defer os.Clearenv()
 
 	loader := LoaderFor(&TestConfig{}).
 		SkipDefaults().
 		SkipFiles().
 		SkipFlags().
-		WithEnvPrefix("tst").
+		WithEnvPrefix("TST").
 		Build()
 
 	var cfg TestConfig
@@ -259,9 +259,9 @@ func TestLoadFlag(t *testing.T) {
 		"-tst.str=str-flag",
 		"-tst.int=1001",
 		"-tst.int=1001",
-		"-tst.httpport=30000",
+		"-tst.http_port=30000",
 		"-tst.sub.float=123.321",
-		"-tst.anon.isanon=true",
+		"-tst.anon.is_anon=true",
 		"-tst.em=em-flag",
 	}
 
@@ -448,14 +448,14 @@ func TestBadFiles(t *testing.T) {
 }
 
 func TestBadEnvs(t *testing.T) {
-	setEnv(t, "TST_HTTPPORT", "30a00")
+	setEnv(t, "TST_HTTP_PORT", "30a00")
 	defer os.Clearenv()
 
 	loader := LoaderFor(&TestConfig{}).
 		SkipDefaults().
 		SkipFiles().
 		SkipFlags().
-		WithEnvPrefix("tst").
+		WithEnvPrefix("TST").
 		Build()
 
 	var cfg TestConfig

example_test.go

@@ -9,8 +9,8 @@ import (
 )
 
 type MyConfig struct {
-	Port int `default:"1111"`
-	Auth struct {
+	HTTPPort int `default:"1111"`
+	Auth     struct {
 		User string `default:"def-user"`
 		Pass string `default:"def-pass"`
 	}
@@ -29,13 +29,13 @@ func Example_NewApi() {
 		log.Panic(err)
 	}
 
-	fmt.Printf("Port:      %v\n", cfg.Port)
+	fmt.Printf("HTTPPort:  %v\n", cfg.HTTPPort)
 	fmt.Printf("Auth.User: %q\n", cfg.Auth.User)
 	fmt.Printf("Auth.Pass: %q\n", cfg.Auth.Pass)
 
 	// Output:
 	//
-	// Port:      0
+	// HTTPPort:  0
 	// Auth.User: ""
 	// Auth.Pass: ""
 }
@@ -54,13 +54,13 @@ func Example_Defaults() {
 		log.Panic(err)
 	}
 
-	fmt.Printf("Port:      %v\n", cfg.Port)
+	fmt.Printf("HTTPPort:  %v\n", cfg.HTTPPort)
 	fmt.Printf("Auth.User: %v\n", cfg.Auth.User)
 	fmt.Printf("Auth.Pass: %v\n", cfg.Auth.Pass)
 
 	// Output:
 	//
-	// Port:      1111
+	// HTTPPort:  1111
 	// Auth.User: def-user
 	// Auth.Pass: def-pass
 }
@@ -79,13 +79,13 @@ func Example_File() {
 		log.Panic(err)
 	}
 
-	fmt.Printf("Port:      %v\n", cfg.Port)
+	fmt.Printf("HTTPPort:  %v\n", cfg.HTTPPort)
 	fmt.Printf("Auth.User: %v\n", cfg.Auth.User)
 	fmt.Printf("Auth.Pass: %v\n", cfg.Auth.Pass)
 
 	// Output:
 	//
-	// Port:      2222
+	// HTTPPort:  2222
 	// Auth.User: json-user
 	// Auth.Pass: json-pass
 }
@@ -94,7 +94,7 @@ func Example_File() {
 // And then overwrite with environment variables.
 //
 func Example_Env() {
-	os.Setenv("EXAMPLE_PORT", "3333")
+	os.Setenv("EXAMPLE_HTTP_PORT", "3333")
 	os.Setenv("EXAMPLE_AUTH_USER", "env-user")
 	os.Setenv("EXAMPLE_AUTH_PASS", "env-pass")
 	defer os.Clearenv()
@@ -110,13 +110,13 @@ func Example_Env() {
 		log.Panic(err)
 	}
 
-	fmt.Printf("Port:      %v\n", cfg.Port)
+	fmt.Printf("HTTPPort:  %v\n", cfg.HTTPPort)
 	fmt.Printf("Auth.User: %v\n", cfg.Auth.User)
 	fmt.Printf("Auth.Pass: %v\n", cfg.Auth.Pass)
 
 	// Output:
 	//
-	// Port:      3333
+	// HTTPPort:  3333
 	// Auth.User: env-user
 	// Auth.Pass: env-pass
 }
@@ -140,7 +140,7 @@ func Example_Flag() {
 		log.Panic(err)
 	}
 
-	fmt.Printf("Port:      %v\n", cfg.Port)
+	fmt.Printf("HTTPPort:  %v\n", cfg.HTTPPort)
 	fmt.Printf("Auth.User: %v\n", cfg.Auth.User)
 	fmt.Printf("Auth.Pass: %v\n", cfg.Auth.Pass)
 
@@ -150,7 +150,7 @@ func Example_Flag() {
 
 	// Output
 	//
-	// Port:      4444
+	// HTTPPort:  4444
 	// Auth.User: flag-user
 	// Auth.Pass: flag-pass
 }

testdata/example_config.json

@@ -1,5 +1,5 @@
 {
-  "Port": 2222,
+  "HTTPPort": 2222,
   "Auth": {
     "User": "json-user",
     "Pass": "json-pass"