diff --git a/file.go b/file.go
index 9dff097..7ac7910 100644
--- a/file.go
+++ b/file.go
@@ -7,6 +7,7 @@ import (
 	"io/ioutil"
 	"os"
 
+	"github.com/imdario/mergo"
 	"github.com/unistack-org/micro/v3/codec"
 	"github.com/unistack-org/micro/v3/config"
 )
@@ -62,7 +63,13 @@ func (c *fileConfig) Load(ctx context.Context) error {
 		var buf []byte
 		buf, err = ioutil.ReadAll(io.LimitReader(fp, int64(codec.DefaultMaxMsgSize)))
 		if err == nil {
-			err = c.opts.Codec.Unmarshal(buf, c.opts.Struct)
+			src, err := config.Zero(c.opts.Struct)
+			if err == nil {
+				err = c.opts.Codec.Unmarshal(buf, src)
+				if err == nil {
+					err = mergo.Merge(c.opts.Struct, src, mergo.WithOverride, mergo.WithTypeCheck, mergo.WithAppendSlice)
+				}
+			}
 		}
 		if err != nil && !c.opts.AllowFail {
 			return err
diff --git a/go.mod b/go.mod
index a1429a7..12b29f6 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,7 @@ module github.com/unistack-org/micro-config-file
 
 go 1.15
 
-require github.com/unistack-org/micro/v3 v3.0.2-0.20201219202205-150e8ad698bb
+require (
+	github.com/imdario/mergo v0.3.11
+	github.com/unistack-org/micro/v3 v3.0.2-0.20201219211529-b50855855b58
+)
diff --git a/go.sum b/go.sum
index 50d3b5c..906795c 100644
--- a/go.sum
+++ b/go.sum
@@ -136,6 +136,8 @@ github.com/hashicorp/golang-lru v0.5.3 h1:YPkqC67at8FYaadspW/6uE0COsBxS2656RLEr8
 github.com/hashicorp/golang-lru v0.5.3/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/iij/doapi v0.0.0-20190504054126-0bbf12d6d7df/go.mod h1:QMZY7/J/KSQEhKWFeDesPjMj+wCHReeknARU3wqlyN4=
+github.com/imdario/mergo v0.3.11 h1:3tnifQM4i+fbajXKBHXWEH+KvNHqojZ778UH75j3bGA=
+github.com/imdario/mergo v0.3.11/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
 github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=
 github.com/json-iterator/go v1.1.5/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
@@ -243,6 +245,8 @@ github.com/unistack-org/micro/v3 v3.0.2-0.20201213102644-92aec349c3d4 h1:SmwEx/E
 github.com/unistack-org/micro/v3 v3.0.2-0.20201213102644-92aec349c3d4/go.mod h1:0DgOy4OdJxQCDER8YSKitZugd2+1bddrRSNfeooTHDc=
 github.com/unistack-org/micro/v3 v3.0.2-0.20201219202205-150e8ad698bb h1:cJGF8j30idReDyjRCvEJN5waWCh/AKuiKEqLA8OLMlY=
 github.com/unistack-org/micro/v3 v3.0.2-0.20201219202205-150e8ad698bb/go.mod h1:0DgOy4OdJxQCDER8YSKitZugd2+1bddrRSNfeooTHDc=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201219211529-b50855855b58 h1:cxBL1qxHsugjajAf/N14Lmk8V1KL1LH9rMGnYEokrpI=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201219211529-b50855855b58/go.mod h1:0DgOy4OdJxQCDER8YSKitZugd2+1bddrRSNfeooTHDc=
 github.com/urfave/cli v1.22.1/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
 github.com/vultr/govultr v0.1.4/go.mod h1:9H008Uxr/C4vFNGLqKx232C206GL0PBHzOP0809bGNA=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=