feat: support env tag in config

core/hash/consistenthash.go

@@ -7,7 +7,6 @@ import (
 	"sync"
 
 	"github.com/zeromicro/go-zero/core/lang"
-	"github.com/zeromicro/go-zero/core/mapping"
 )
 
 const (
@@ -183,5 +182,5 @@ func innerRepr(node interface{}) string {
 }
 
 func repr(node interface{}) string {
-	return mapping.Repr(node)
+	return lang.Repr(node)
 }

core/lang/lang.go

@@ -1,5 +1,11 @@
 package lang
 
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+)
+
 // Placeholder is a placeholder object that can be used globally.
 var Placeholder PlaceholderType
 
@@ -9,3 +15,64 @@ type (
 	// PlaceholderType represents a placeholder type.
 	PlaceholderType = struct{}
 )
+
+// Repr returns the string representation of v.
+func Repr(v interface{}) string {
+	if v == nil {
+		return ""
+	}
+
+	// if func (v *Type) String() string, we can't use Elem()
+	switch vt := v.(type) {
+	case fmt.Stringer:
+		return vt.String()
+	}
+
+	val := reflect.ValueOf(v)
+	if val.Kind() == reflect.Ptr && !val.IsNil() {
+		val = val.Elem()
+	}
+
+	return reprOfValue(val)
+}
+
+func reprOfValue(val reflect.Value) string {
+	switch vt := val.Interface().(type) {
+	case bool:
+		return strconv.FormatBool(vt)
+	case error:
+		return vt.Error()
+	case float32:
+		return strconv.FormatFloat(float64(vt), 'f', -1, 32)
+	case float64:
+		return strconv.FormatFloat(vt, 'f', -1, 64)
+	case fmt.Stringer:
+		return vt.String()
+	case int:
+		return strconv.Itoa(vt)
+	case int8:
+		return strconv.Itoa(int(vt))
+	case int16:
+		return strconv.Itoa(int(vt))
+	case int32:
+		return strconv.Itoa(int(vt))
+	case int64:
+		return strconv.FormatInt(vt, 10)
+	case string:
+		return vt
+	case uint:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint8:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint16:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint32:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint64:
+		return strconv.FormatUint(vt, 10)
+	case []byte:
+		return string(vt)
+	default:
+		return fmt.Sprint(val.Interface())
+	}
+}

core/lang/lang_test.go

@@ -0,0 +1,131 @@
+package lang
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRepr(t *testing.T) {
+	var (
+		f32 float32 = 1.1
+		f64         = 2.2
+		i8  int8    = 1
+		i16 int16   = 2
+		i32 int32   = 3
+		i64 int64   = 4
+		u8  uint8   = 5
+		u16 uint16  = 6
+		u32 uint32  = 7
+		u64 uint64  = 8
+	)
+	tests := []struct {
+		v      interface{}
+		expect string
+	}{
+		{
+			nil,
+			"",
+		},
+		{
+			mockStringable{},
+			"mocked",
+		},
+		{
+			new(mockStringable),
+			"mocked",
+		},
+		{
+			newMockPtr(),
+			"mockptr",
+		},
+		{
+			&mockOpacity{
+				val: 1,
+			},
+			"{1}",
+		},
+		{
+			true,
+			"true",
+		},
+		{
+			false,
+			"false",
+		},
+		{
+			f32,
+			"1.1",
+		},
+		{
+			f64,
+			"2.2",
+		},
+		{
+			i8,
+			"1",
+		},
+		{
+			i16,
+			"2",
+		},
+		{
+			i32,
+			"3",
+		},
+		{
+			i64,
+			"4",
+		},
+		{
+			u8,
+			"5",
+		},
+		{
+			u16,
+			"6",
+		},
+		{
+			u32,
+			"7",
+		},
+		{
+			u64,
+			"8",
+		},
+		{
+			[]byte(`abcd`),
+			"abcd",
+		},
+		{
+			mockOpacity{val: 1},
+			"{1}",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.expect, func(t *testing.T) {
+			assert.Equal(t, test.expect, Repr(test.v))
+		})
+	}
+}
+
+type mockStringable struct{}
+
+func (m mockStringable) String() string {
+	return "mocked"
+}
+
+type mockPtr struct{}
+
+func newMockPtr() *mockPtr {
+	return new(mockPtr)
+}
+
+func (m *mockPtr) String() string {
+	return "mockptr"
+}
+
+type mockOpacity struct {
+	val int
+}

core/mapping/fieldoptions.go

@@ -13,6 +13,7 @@ type (
 		Optional   bool
 		Options    []string
 		Default    string
+		EnvVar     string
 		Range      *numberRange
 	}
 
@@ -106,5 +107,6 @@ func (o *fieldOptions) toOptionsWithContext(key string, m Valuer, fullName strin
 		Optional:   optional,
 		Options:    o.Options,
 		Default:    o.Default,
+		EnvVar:     o.EnvVar,
 	}, nil
 }

core/mapping/unmarshaler.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/zeromicro/go-zero/core/jsonx"
 	"github.com/zeromicro/go-zero/core/lang"
+	"github.com/zeromicro/go-zero/core/proc"
 	"github.com/zeromicro/go-zero/core/stringx"
 )
 
@@ -92,8 +93,7 @@ func (u *Unmarshaler) unmarshalWithFullName(m valuerWithParent, v interface{}, f
 	rve := rv.Elem()
 	numFields := rte.NumField()
 	for i := 0; i < numFields; i++ {
-		field := rte.Field(i)
-		if err := u.processField(field, rve.Field(i), m, fullName); err != nil {
+		if err := u.processField(rte.Field(i), rve.Field(i), m, fullName); err != nil {
 			return err
 		}
 	}
@@ -338,6 +338,24 @@ func (u *Unmarshaler) processFieldTextUnmarshaler(field reflect.StructField, val
 	return false, nil
 }
 
+func (u *Unmarshaler) processFieldWithEnvValue(field reflect.StructField, value reflect.Value,
+	envVal string, opts *fieldOptionsWithContext, fullName string) error {
+	fieldKind := field.Type.Kind()
+	switch fieldKind {
+	case durationType.Kind():
+		if err := fillDurationValue(fieldKind, value, envVal); err != nil {
+			return fmt.Errorf("unmarshal field %q with environment variable, %w", fullName, err)
+		}
+
+		return nil
+	case reflect.String:
+		value.SetString(envVal)
+		return nil
+	default:
+		return u.processFieldPrimitiveWithJSONNumber(field, value, json.Number(envVal), opts, fullName)
+	}
+}
+
 func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect.Value,
 	m valuerWithParent, fullName string) error {
 	key, opts, err := u.parseOptionsWithContext(field, m, fullName)
@@ -346,6 +364,13 @@ func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect
 	}
 
 	fullName = join(fullName, key)
+	if opts != nil && len(opts.EnvVar) > 0 {
+		envVal := proc.Env(opts.EnvVar)
+		if len(envVal) > 0 {
+			return u.processFieldWithEnvValue(field, value, envVal, opts, fullName)
+		}
+	}
+
 	canonicalKey := key
 	if u.opts.canonicalKey != nil {
 		canonicalKey = u.opts.canonicalKey(key)