Add initial project structure with Go Fiber framework and environment configuration

4 files changed, 247 insertions, 0 deletions

diff --git a/utils/env/functions.go b/utils/env/functions.go
new file mode 100644
index 0000000..de03793
--- /dev/null
+++ b/utils/env/functions.go
@@ -0,0 +1,97 @@
+package env
+
+import (
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func getEnv(key, defaultVal string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return defaultVal
+}
+
+func getEnvBool(key string, defaultVal bool) bool {
+	if value := os.Getenv(key); value != "" {
+		if parsed, err := strconv.ParseBool(value); err == nil {
+			return parsed
+		}
+	}
+	return defaultVal
+}
+
+func getEnvDuration(key string, defaultVal time.Duration) time.Duration {
+	if value := os.Getenv(key); value != "" {
+		if parsed, err := time.ParseDuration(value); err == nil {
+			return parsed
+		}
+	}
+	return defaultVal
+}
+
+func getEnvInt(key string, defaultVal int64) int64 {
+	if value := os.Getenv(key); value != "" {
+		if parsed, err := strconv.ParseInt(value, 10, 64); err == nil {
+			return parsed
+		}
+	}
+	return defaultVal
+}
+
+func getEnvFloat(key string, defaultVal float64) float64 {
+	if value := os.Getenv(key); value != "" {
+		if parsed, err := strconv.ParseFloat(value, 64); err == nil {
+			return parsed
+		}
+	}
+	return defaultVal
+}
+
+func getEnvStringSlice(key string, defaultVal []string) []string {
+	if value := os.Getenv(key); value != "" {
+		parts := strings.Split(value, ",")
+		result := make([]string, 0, len(parts))
+		for _, part := range parts {
+			trimmed := strings.TrimSpace(part)
+			if trimmed != "" {
+				result = append(result, trimmed)
+			}
+		}
+		return result
+	}
+	return defaultVal
+}
+
+func Defaults[T any](config *T) *T {
+	v := reflect.ValueOf(config)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return config
+	}
+
+	elem := v.Elem()
+	t := elem.Type()
+	newStruct := reflect.New(t)
+	newElem := newStruct.Elem()
+
+	for i := range elem.NumField() {
+		field := newElem.Field(i)
+		fieldType := t.Field(i)
+
+		if !field.CanSet() {
+			continue
+		}
+
+		defaultVal := fieldType.Tag.Get("default")
+		if defaultVal == "" {
+			continue
+		}
+
+		setFieldDefault(field, defaultVal)
+	}
+
+	return newStruct.Interface().(*T)
+}
diff --git a/utils/env/parser.go b/utils/env/parser.go
new file mode 100644
index 0000000..c1fdb53
--- /dev/null
+++ b/utils/env/parser.go
@@ -0,0 +1,28 @@
+package env
+
+func Parse(config any) error {
+	elem, t, err := validateConfigInput(config)
+	if err != nil {
+		return err
+	}
+
+	for i := range elem.NumField() {
+		field := elem.Field(i)
+		fieldType := t.Field(i)
+
+		if !field.CanSet() {
+			continue
+		}
+
+		envKey := fieldType.Tag.Get("env")
+		defaultVal := fieldType.Tag.Get("default")
+
+		if envKey == "" {
+			continue
+		}
+
+		setFieldFromEnv(field, envKey, defaultVal)
+	}
+
+	return nil
+}
diff --git a/utils/env/setters.go b/utils/env/setters.go
new file mode 100644
index 0000000..7e42274
--- /dev/null
+++ b/utils/env/setters.go
@@ -0,0 +1,107 @@
+package env
+
+import (
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func setFieldFromEnv(field reflect.Value, envKey, defaultVal string) {
+	switch field.Kind() {
+	case reflect.String:
+		field.SetString(getEnv(envKey, defaultVal))
+	case reflect.Bool:
+		defaultBool, _ := strconv.ParseBool(defaultVal)
+		field.SetBool(getEnvBool(envKey, defaultBool))
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		defaultInt, _ := strconv.ParseInt(defaultVal, 10, 64)
+		field.SetInt(getEnvInt(envKey, defaultInt))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		defaultUint, _ := strconv.ParseUint(defaultVal, 10, 64)
+		setUintField(field, envKey, defaultUint)
+	case reflect.Float32, reflect.Float64:
+		defaultFloat, _ := strconv.ParseFloat(defaultVal, 64)
+		field.SetFloat(getEnvFloat(envKey, defaultFloat))
+	case reflect.Slice:
+		setSliceField(field, envKey, defaultVal)
+	default:
+		setDurationField(field, envKey, defaultVal)
+	}
+}
+
+func setUintField(field reflect.Value, envKey string, defaultVal uint64) {
+	if value := os.Getenv(envKey); value != "" {
+		if parsed, err := strconv.ParseUint(value, 10, 64); err == nil {
+			field.SetUint(parsed)
+			return
+		}
+	}
+	field.SetUint(defaultVal)
+}
+
+func setDurationField(field reflect.Value, envKey, defaultVal string) {
+	if field.Type() == reflect.TypeFor[time.Duration]() {
+		defaultDuration, _ := time.ParseDuration(defaultVal)
+		field.Set(reflect.ValueOf(getEnvDuration(envKey, defaultDuration)))
+	}
+}
+
+func setSliceField(field reflect.Value, envKey, defaultVal string) {
+	if field.Type().Elem().Kind() == reflect.String {
+		var defaultSlice []string
+		if defaultVal != "" {
+			parts := strings.Split(defaultVal, ",")
+			for _, part := range parts {
+				trimmed := strings.TrimSpace(part)
+				if trimmed != "" {
+					defaultSlice = append(defaultSlice, trimmed)
+				}
+			}
+		}
+		result := getEnvStringSlice(envKey, defaultSlice)
+		field.Set(reflect.ValueOf(result))
+	}
+}
+
+func setFieldDefault(field reflect.Value, defaultVal string) {
+	switch field.Kind() {
+	case reflect.String:
+		field.SetString(defaultVal)
+	case reflect.Bool:
+		if defaultBool, err := strconv.ParseBool(defaultVal); err == nil {
+			field.SetBool(defaultBool)
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		if defaultInt, err := strconv.ParseInt(defaultVal, 10, 64); err == nil {
+			field.SetInt(defaultInt)
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		if defaultUint, err := strconv.ParseUint(defaultVal, 10, 64); err == nil {
+			field.SetUint(defaultUint)
+		}
+	case reflect.Float32, reflect.Float64:
+		if defaultFloat, err := strconv.ParseFloat(defaultVal, 64); err == nil {
+			field.SetFloat(defaultFloat)
+		}
+	case reflect.Slice:
+		if field.Type().Elem().Kind() == reflect.String && defaultVal != "" {
+			parts := strings.Split(defaultVal, ",")
+			result := make([]string, 0, len(parts))
+			for _, part := range parts {
+				trimmed := strings.TrimSpace(part)
+				if trimmed != "" {
+					result = append(result, trimmed)
+				}
+			}
+			field.Set(reflect.ValueOf(result))
+		}
+	default:
+		if field.Type() == reflect.TypeFor[time.Duration]() {
+			if defaultDuration, err := time.ParseDuration(defaultVal); err == nil {
+				field.Set(reflect.ValueOf(defaultDuration))
+			}
+		}
+	}
+}
diff --git a/utils/env/validators.go b/utils/env/validators.go
new file mode 100644
index 0000000..fa9b17f
--- /dev/null
+++ b/utils/env/validators.go
@@ -0,0 +1,15 @@
+package env
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func validateConfigInput(config any) (reflect.Value, reflect.Type, error) {
+	v := reflect.ValueOf(config)
+	if v.Kind() != reflect.Pointer || v.Elem().Kind() != reflect.Struct {
+		return reflect.Value{}, nil, fmt.Errorf("config must be a pointer to struct")
+	}
+	elem := v.Elem()
+	return elem, elem.Type(), nil
+}