refactor: use structure to present the status of env var

envconf.go

@@ -17,31 +17,39 @@ import (
 // 2. Duplicated field tags will be assigned with the same environment variable.
 func Load(prefix string, out interface{}, opts ...Option) {
 	loader := loader{}
-	loader.envStatus = map[string]bool{}
-	loader.handleEnvironmentVariables = func(map[string]bool) {}
+	loader.envStatuses = map[string]*EnvStatus{}
+	loader.handleEnvironmentVariables = func(map[string]*EnvStatus) {}
 	for _, opt := range opts {
 		opt(&loader)
 	}
 
 	val := reflect.ValueOf(out).Elem()
 	loader.loadStruct(strings.ToUpper(prefix), &val)
 
-	loader.handleEnvironmentVariables(loader.envStatus)
+	loader.handleEnvironmentVariables(loader.envStatuses)
 }
 
 type loader struct {
-	handleEnvironmentVariables func(map[string]bool)
-	envStatus                  map[string]bool
+	handleEnvironmentVariables func(map[string]*EnvStatus)
+	envStatuses                map[string]*EnvStatus
 }
 
 func (l *loader) useKey(name string) error {
-	if _, ok := l.envStatus[name]; ok {
+	if _, ok := l.envStatuses[name]; ok {
 		return fmt.Errorf("Duplicated key %v", name)
 	}
-	l.envStatus[name] = false
+	l.envStatuses[name] = &EnvStatus{}
 	return nil
 }
 
+type EnvStatus struct {
+	Loaded bool
+}
+
+func (e *EnvStatus) SetLoaded() {
+	e.Loaded = true
+}
+
 var stringSliceType = reflect.TypeOf([]string{})
 
 func (l *loader) loadField(name string, out *reflect.Value) {
@@ -141,7 +149,7 @@ func (l *loader) loadString(name string, out *reflect.Value) {
 	if !found {
 		return
 	}
-	l.envStatus[name] = true
+	l.envStatuses[name].SetLoaded()
 
 	out.SetString(data)
 }
@@ -151,7 +159,7 @@ func (l *loader) loadInt(name string, out *reflect.Value) {
 	if !found {
 		return
 	}
-	l.envStatus[name] = true
+	l.envStatuses[name].SetLoaded()
 
 	d, err := strconv.ParseInt(data, 10, 64)
 	if err != nil {
@@ -166,7 +174,7 @@ func (l *loader) loadUint(name string, out *reflect.Value) {
 	if !found {
 		return
 	}
-	l.envStatus[name] = true
+	l.envStatuses[name].SetLoaded()
 
 	d, err := strconv.ParseUint(data, 10, 64)
 	if err != nil {
@@ -181,7 +189,7 @@ func (l *loader) loadBool(name string, out *reflect.Value) {
 	if !found {
 		return
 	}
-	l.envStatus[name] = true
+	l.envStatuses[name].SetLoaded()
 
 	isTrue := data == "true" || data == "TRUE" || data == "True" || data == "1"
 	isFalse := data == "false" || data == "FALSE" || data == "False" || data == "0"
@@ -198,7 +206,7 @@ func (l *loader) loadStringSlice(name string, out *reflect.Value) {
 	if !found {
 		return
 	}
-	l.envStatus[name] = true
+	l.envStatuses[name].SetLoaded()
 
 	strListRaw := strings.Split(data, ",")
 	strList := []string{}

envconf_test.go

@@ -318,7 +318,7 @@ func TestLogger(t *testing.T) {
 	os.Setenv("TEST_INTEGER", "-3")
 	os.Setenv("TEST_UNSIGNED_INTEGER", "3")
 
-	result := map[string]bool{}
+	result := map[string]*EnvStatus{}
 	config := struct {
 		String  string `env:"string"`
 		Integer int    `env:"integer"`
@@ -328,10 +328,16 @@ func TestLogger(t *testing.T) {
 			StrSlice []string `env:"string_slice"`
 		} `env:",inline"`
 	}{}
-	Load("TEST", &config, CustomHandleEnvVarsOption(func(status map[string]bool) {
+	Load("TEST", &config, CustomHandleEnvVarsOption(func(status map[string]*EnvStatus) {
 		result = status
 	}))
 
-	expected := map[string]bool{"TEST_STRING": false, "TEST_INTEGER": true, "TEST_UNSIGNED_INTEGER": true, "TEST_BOOL": false, "TEST_STRING_SLICE": false}
+	expected := map[string]*EnvStatus{
+		"TEST_STRING":           {false},
+		"TEST_INTEGER":          {true},
+		"TEST_UNSIGNED_INTEGER": {true},
+		"TEST_BOOL":             {false},
+		"TEST_STRING_SLICE":     {false},
+	}
 	assertEqual(t, "", expected, result)
 }

option.go

@@ -7,7 +7,7 @@ type Option func(*loader)
 //
 // The map keys are the environment variable names that are checked by envconf,
 // and the values present whether the corresponding environment variables are set.
-func CustomHandleEnvVarsOption(cb func(map[string]bool)) Option {
+func CustomHandleEnvVarsOption(cb func(map[string]*EnvStatus)) Option {
 	return func(l *loader) {
 		l.handleEnvironmentVariables = cb
 	}

options/predefined.go

@@ -4,12 +4,14 @@ import (
 	"encoding/json"
 	"io"
 	"log"
+
+	"gitlab.rayark.com/backend/envconf"
 )
 
-// LogStatusOfEnvVars will log the status of environment variables used by given structure.
+// MakeJSONLogger will log the status of environment variables used by given structure.
 // The message is in JSON format.
-func LogStatusOfEnvVars(w io.Writer) func(map[string]bool) {
-	return func(status map[string]bool) {
+func MakeJSONLogger(w io.Writer) func(map[string]*envconf.EnvStatus) {
+	return func(status map[string]*envconf.EnvStatus) {
 		logger := log.New(w, "", 0)
 
 		result := map[string]interface{}{}

options/predefined_test.go

@@ -18,7 +18,7 @@ func TestLogger(t *testing.T) {
 		Integer int    `env:"integer"`
 	}{}
 	buf := bytes.NewBuffer(nil)
-	envconf.Load("TEST", &config, envconf.CustomHandleEnvVarsOption(options.LogStatusOfEnvVars(buf)))
+	envconf.Load("TEST", &config, envconf.CustomHandleEnvVarsOption(options.MakeJSONLogger(buf)))
 
 	if buf.String() == "" {
 		t.Errorf("failed to log environment variable status")