feat: add slice environment variables

.golangci.yml

@@ -6,6 +6,7 @@ linters:
     - exhaustruct
     - wrapcheck
     - wsl
+    - tagalign
   settings:
     lll:
       # Max line length, lines longer will be reported.
@@ -15,17 +16,6 @@ linters:
       # Tab width in spaces.
       # Default: 1
       tab-width: 1
-    tagliatelle:
-      # Checks the struct tag name case.
-      case:
-        rules:
-          json: snake
-          yaml: snake
-          mapstructure: snake
-          whatever: snake
-    recvcheck:
-      exclusions:
-        - "*.UnmarshalJSON"
     wsl_v5:
       allow-first-in-block: true
       allow-whole-block: false

any.go

@@ -34,22 +34,6 @@ func NewEnvAnyVariable(name string) EnvAny {
 	}
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvAny) UnmarshalJSON(b []byte) error {
-	type Plain EnvAny
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	*ev = EnvAny(rawValue)
-
-	return nil
-}
-
 // IsZero checks if the instance is empty.
 func (ev EnvAny) IsZero() bool {
 	return (ev.Variable == nil || *ev.Variable == "") &&

environment.go

@@ -2,7 +2,6 @@
 package goenvconf
 
 import (
-	"encoding/json"
 	"errors"
 	"os"
 	"strconv"
@@ -39,27 +38,6 @@ func NewEnvStringVariable(name string) EnvString {
 	}
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvString) UnmarshalJSON(b []byte) error {
-	type Plain EnvString
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	value := EnvString(rawValue)
-	if value.IsZero() {
-		return ErrEnvironmentValueRequired
-	}
-
-	*ev = value
-
-	return nil
-}
-
 // IsZero checks if the instance is empty.
 func (ev EnvString) IsZero() bool {
 	return (ev.Variable == nil || *ev.Variable == "") &&
@@ -185,27 +163,6 @@ func (ev EnvInt) Equal(target EnvInt) bool {
 		(ev.Variable != nil && target.Variable != nil && *ev.Variable == *target.Variable)
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvInt) UnmarshalJSON(b []byte) error {
-	type Plain EnvInt
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	value := EnvInt(rawValue)
-	if value.IsZero() {
-		return ErrEnvironmentValueRequired
-	}
-
-	*ev = value
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvInt) Get() (int64, error) {
 	if ev.IsZero() {
@@ -310,27 +267,6 @@ func (ev EnvBool) Equal(target EnvBool) bool {
 		(ev.Variable != nil && target.Variable != nil && *ev.Variable == *target.Variable)
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvBool) UnmarshalJSON(b []byte) error {
-	type Plain EnvBool
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	value := EnvBool(rawValue)
-	if value.IsZero() {
-		return ErrEnvironmentValueRequired
-	}
-
-	*ev = value
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvBool) Get() (bool, error) {
 	if ev.IsZero() {
@@ -435,27 +371,6 @@ func (ev EnvFloat) Equal(target EnvFloat) bool {
 		(ev.Variable != nil && target.Variable != nil && *ev.Variable == *target.Variable)
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvFloat) UnmarshalJSON(b []byte) error {
-	type Plain EnvFloat
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	value := EnvFloat(rawValue)
-	if value.IsZero() {
-		return ErrEnvironmentValueRequired
-	}
-
-	*ev = value
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvFloat) Get() (float64, error) {
 	if ev.IsZero() {

error.go

@@ -0,0 +1,47 @@
+package goenvconf
+
+import "fmt"
+
+var (
+	// ErrEnvironmentValueRequired occurs when both value and env fields are null or empty.
+	ErrEnvironmentValueRequired = ParseEnvError{
+		Code:   "EmptyEnv",
+		Detail: "require either value or env",
+	}
+
+	// ErrEnvironmentVariableValueRequired the error occurs when the value from environment variable is empty.
+	ErrEnvironmentVariableValueRequired = ParseEnvError{
+		Code:   "EmptyVar",
+		Detail: "the environment variable value is empty",
+	}
+)
+
+const (
+	// ErrCodeParseEnvFailed is the error code when parsing environment variable failed.
+	ErrCodeParseEnvFailed = "ParseEnvFailed"
+)
+
+// ParseEnvError structures a detailed error for parsed env.
+type ParseEnvError struct {
+	Code   string `json:"code"           jsonschema:"enum=EmptyEnv,enum=EmptyVar,enum=ParseEnvFailed"`
+	Detail string `json:"detail"`
+	Hint   string `json:"hint,omitempty"`
+}
+
+// NewParseEnvFailedError creates a [ParseEnvError] for parsing env variable errors.
+func NewParseEnvFailedError(detail string, hint string) ParseEnvError {
+	return ParseEnvError{
+		Code:   ErrCodeParseEnvFailed,
+		Detail: detail,
+		Hint:   hint,
+	}
+}
+
+// Error returns the error message.
+func (pee ParseEnvError) Error() string {
+	if pee.Hint != "" {
+		return fmt.Sprintf("%s: %s. Hint: %s", pee.Code, pee.Detail, pee.Hint)
+	}
+
+	return pee.Code + ": " + pee.Detail
+}

map.go

@@ -1,7 +1,6 @@
 package goenvconf
 
 import (
-	"encoding/json"
 	"maps"
 	"os"
 )
@@ -52,22 +51,6 @@ func (ev EnvMapString) Equal(target EnvMapString) bool {
 		(ev.Value != nil && target.Value != nil && maps.Equal(ev.Value, target.Value))
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvMapString) UnmarshalJSON(b []byte) error {
-	type Plain EnvMapString
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	*ev = EnvMapString(rawValue)
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvMapString) Get() (map[string]string, error) {
 	if ev.Variable != nil && *ev.Variable != "" {
@@ -142,22 +125,6 @@ func (ev EnvMapInt) Equal(target EnvMapInt) bool {
 		(ev.Value != nil && target.Value != nil && maps.Equal(ev.Value, target.Value))
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvMapInt) UnmarshalJSON(b []byte) error {
-	type Plain EnvMapInt
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	*ev = EnvMapInt(rawValue)
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvMapInt) Get() (map[string]int64, error) {
 	if ev.Variable != nil && *ev.Variable != "" {
@@ -232,22 +199,6 @@ func (ev EnvMapFloat) Equal(target EnvMapFloat) bool {
 		(ev.Value != nil && target.Value != nil && maps.Equal(ev.Value, target.Value))
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvMapFloat) UnmarshalJSON(b []byte) error {
-	type Plain EnvMapFloat
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	*ev = EnvMapFloat(rawValue)
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvMapFloat) Get() (map[string]float64, error) {
 	if ev.Variable != nil && *ev.Variable != "" {
@@ -322,22 +273,6 @@ func (ev EnvMapBool) Equal(target EnvMapBool) bool {
 		(ev.Value != nil && target.Value != nil && maps.Equal(ev.Value, target.Value))
 }
 
-// UnmarshalJSON implements json.Unmarshaler.
-func (ev *EnvMapBool) UnmarshalJSON(b []byte) error {
-	type Plain EnvMapBool
-
-	var rawValue Plain
-
-	err := json.Unmarshal(b, &rawValue)
-	if err != nil {
-		return err
-	}
-
-	*ev = EnvMapBool(rawValue)
-
-	return nil
-}
-
 // Get gets literal value or from system environment.
 func (ev EnvMapBool) Get() (map[string]bool, error) {
 	if ev.Variable != nil && *ev.Variable != "" {

map_test.go

@@ -68,7 +68,7 @@ func TestEnvMapString_GetCustom(t *testing.T) {
 			Name:     "invalid_map_format",
 			Input:    NewEnvMapStringVariable("INVALID_MAP"),
 			GetFunc:  mockGetEnvFuncForMaps(map[string]string{"INVALID_MAP": "invalid_format_no_equals"}, false),
-			ErrorMsg: ErrParseStringFailed.Error(),
+			ErrorMsg: "ParseEnvFailed",
 		},
 	}
 
@@ -133,7 +133,7 @@ func TestEnvMapInt_GetCustom(t *testing.T) {
 			Name:     "invalid_int_value",
 			Input:    NewEnvMapIntVariable("INVALID_MAP"),
 			GetFunc:  mockGetEnvFuncForMaps(map[string]string{"INVALID_MAP": "key=not_a_number"}, false),
-			ErrorMsg: ErrParseStringFailed.Error(),
+			ErrorMsg: "ParseEnvFailed",
 		},
 	}
 
@@ -198,7 +198,7 @@ func TestEnvMapFloat_GetCustom(t *testing.T) {
 			Name:     "invalid_float_value",
 			Input:    NewEnvMapFloatVariable("INVALID_MAP"),
 			GetFunc:  mockGetEnvFuncForMaps(map[string]string{"INVALID_MAP": "key=not_a_float"}, false),
-			ErrorMsg: ErrParseStringFailed.Error(),
+			ErrorMsg: "ParseEnvFailed",
 		},
 	}
 
@@ -263,7 +263,7 @@ func TestEnvMapBool_GetCustom(t *testing.T) {
 			Name:     "invalid_bool_value",
 			Input:    NewEnvMapBoolVariable("INVALID_MAP"),
 			GetFunc:  mockGetEnvFuncForMaps(map[string]string{"INVALID_MAP": "key=not_a_bool"}, false),
-			ErrorMsg: ErrParseStringFailed.Error(),
+			ErrorMsg: "ParseEnvFailed",
 		},
 	}