fix: #46 BindStruct doesn't seem to work with env var substitution

Signed-off-by: inhere <in.798@qq.com>

config.go

@@ -42,9 +42,11 @@ package config
 import (
 	"fmt"
 	"os"
+	"reflect"
 	"strings"
 	"sync"
 
+	"github.com/gookit/goutil/envutil"
 	"github.com/mitchellh/mapstructure"
 )
 
@@ -203,6 +205,19 @@ func newDefaultDecoderConfig() *mapstructure.DecoderConfig {
 		TagName: defaultStructTag,
 		// will auto convert string to int/uint
 		WeaklyTypedInput: true,
+		// DecodeHook: ParseEnvVarStringHookFunc,
+	}
+}
+
+// ParseEnvVarStringHookFunc returns a DecodeHookFunc that parse ENV var
+func ParseEnvVarStringHookFunc() mapstructure.DecodeHookFunc {
+	return func(f reflect.Type, t reflect.Type, data interface{}) (interface{}, error) {
+		if f.Kind() != reflect.String {
+			return data, nil
+		}
+
+		str := envutil.ParseEnvValue(data.(string))
+		return str, nil
 	}
 }
 

export.go

@@ -55,6 +55,11 @@ func (c *Config) Structure(key string, dst interface{}) error {
 		}
 	}
 
+	// parse env var
+	if c.opts.ParseEnv && bindConf.DecodeHook == nil {
+		bindConf.DecodeHook = ParseEnvVarStringHookFunc()
+	}
+
 	bindConf.Result = dst // set result struct ptr
 	decoder, err := mapstructure.NewDecoder(bindConf)
 	if err != nil {

issues_test.go

@@ -7,11 +7,12 @@ import (
 	"github.com/gookit/config/v2/yaml"
 	"github.com/gookit/config/v2/yamlv3"
 	"github.com/gookit/goutil/dump"
+	"github.com/gookit/goutil/testutil"
 	"github.com/stretchr/testify/assert"
 )
 
 // https://github.com/gookit/config/issues/37
-func TestIssues37(t *testing.T) {
+func TestIssues_37(t *testing.T) {
 	is := assert.New(t)
 
 	c := config.New("test")
@@ -66,3 +67,50 @@ lang:
 	is.NoError(err)
 	dump.Println(c.Data())
 }
+
+// BindStruct doesn't seem to work with env var substitution
+// https://github.com/gookit/config/issues/46
+func TestIssues_46(t *testing.T) {
+	is := assert.New(t)
+
+	c := config.New("test").WithOptions(config.ParseEnv)
+	err := c.LoadStrings(config.JSON, `
+{
+  "http": {
+    "port": "${HTTP_PORT|8080}"
+  }
+}
+`)
+
+	is.NoError(err)
+	dump.Println(c.Data())
+
+	val, _ := c.GetValue("http")
+	mp := val.(map[string]interface{})
+	dump.Println(mp)
+	is.Equal("${HTTP_PORT|8080}", mp["port"])
+
+	smp := c.StringMap("http")
+	dump.Println(smp)
+	is.Contains(smp, "port")
+	is.Equal("8080", smp["port"])
+
+	type Http struct {
+		Port int
+	}
+
+	h := &Http{}
+	err = c.BindStruct("http", h)
+	is.NoError(err)
+	dump.Println(h)
+	is.Equal(8080, h.Port)
+
+	testutil.MockEnvValue("HTTP_PORT", "19090", func(_ string) {
+		h := &Http{}
+		err = c.BindStruct("http", h)
+		is.NoError(err)
+		dump.Println(h)
+		is.Equal(19090, h.Port)
+	})
+
+}