diff --git a/create.go b/create.go
index 90dfff7..d50f963 100644
--- a/create.go
+++ b/create.go
@@ -34,10 +34,6 @@ func prepareZipfile(src string, excludes []string) (*os.File, os.FileInfo, error
 }
 
 func (app *App) prepareFunctionCodeForDeploy(ctx context.Context, opt *DeployOption, fn *Function) error {
-	if fn.Layers == nil {
-		fn.Layers = []string{} // set explicitly
-	}
-
 	if fn.PackageType == types.PackageTypeImage {
 		if fn.Code == nil || fn.Code.ImageUri == nil {
 			return fmt.Errorf("PackageType=Image requires Code.ImageUri in function definition")
diff --git a/export_test.go b/export_test.go
index 4b903ad..ac929ef 100644
--- a/export_test.go
+++ b/export_test.go
@@ -5,6 +5,7 @@ var (
 	ExpandExcludeFile = expandExcludeFile
 	LoadZipArchive    = loadZipArchive
 	MergeTags         = mergeTags
+	FillDefaultValues = fillDefaultValues
 )
 
 type VersionsOutput = versionsOutput
diff --git a/lambroll.go b/lambroll.go
index 5596d77..806a1e9 100644
--- a/lambroll.go
+++ b/lambroll.go
@@ -331,10 +331,28 @@ func fillDefaultValues(fn *Function) {
 	if fn.MemorySize == nil {
 		fn.MemorySize = aws.Int32(128)
 	}
-	if fn.LoggingConfig == nil {
+	if fn.Layers == nil {
+		fn.Layers = []string{}
+	}
+	if lc := fn.LoggingConfig; lc == nil {
 		fn.LoggingConfig = &types.LoggingConfig{
-			LogFormat: types.LogFormatText,
-			LogGroup:  aws.String(resolveLogGroup(fn)),
+			LogFormat:           types.LogFormatText,
+			LogGroup:            aws.String(resolveLogGroup(fn)),
+			ApplicationLogLevel: types.ApplicationLogLevelInfo,
+			SystemLogLevel:      types.SystemLogLevelInfo,
+		}
+	} else {
+		if lc.LogFormat == "" {
+			lc.LogFormat = types.LogFormatText
+		}
+		if lc.LogGroup == nil {
+			lc.LogGroup = aws.String(resolveLogGroup(fn))
+		}
+		if lc.ApplicationLogLevel == "" {
+			lc.ApplicationLogLevel = types.ApplicationLogLevelInfo
+		}
+		if lc.SystemLogLevel == "" {
+			lc.SystemLogLevel = types.SystemLogLevelInfo
 		}
 	}
 	if fn.TracingConfig == nil {
diff --git a/lambroll_test.go b/lambroll_test.go
new file mode 100644
index 0000000..cd8ecc2
--- /dev/null
+++ b/lambroll_test.go
@@ -0,0 +1,89 @@
+package lambroll_test
+
+import (
+	"testing"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/lambda/types"
+	"github.com/fujiwara/lambroll"
+	"github.com/google/go-cmp/cmp"
+)
+
+var testCasesFillDefaultValues = []struct {
+	name   string
+	in     *lambroll.Function
+	expect *lambroll.Function
+}{
+	{
+		name: "normal",
+		in:   &lambroll.Function{FunctionName: aws.String("test")},
+		expect: &lambroll.Function{
+			FunctionName:  aws.String("test"),
+			Description:   aws.String(""),
+			Architectures: []types.Architecture{types.ArchitectureX8664},
+			EphemeralStorage: &types.EphemeralStorage{
+				Size: aws.Int32(512),
+			},
+			Layers: []string{},
+			LoggingConfig: &types.LoggingConfig{
+				ApplicationLogLevel: "INFO",
+				LogFormat:           types.LogFormatText,
+				LogGroup:            aws.String("/aws/lambda/test"),
+				SystemLogLevel:      "INFO",
+			},
+			MemorySize: aws.Int32(128),
+			SnapStart: &types.SnapStart{
+				ApplyOn: types.SnapStartApplyOnNone,
+			},
+			Timeout: aws.Int32(3),
+			TracingConfig: &types.TracingConfig{
+				Mode: types.TracingModePassThrough,
+			},
+		},
+	},
+	{
+		name: "logging config JSON",
+		in: &lambroll.Function{
+			FunctionName: aws.String("test"),
+			LoggingConfig: &types.LoggingConfig{
+				LogFormat: types.LogFormatJson,
+			},
+		},
+		expect: &lambroll.Function{
+			FunctionName:  aws.String("test"),
+			Description:   aws.String(""),
+			Architectures: []types.Architecture{types.ArchitectureX8664},
+			EphemeralStorage: &types.EphemeralStorage{
+				Size: aws.Int32(512),
+			},
+			Layers: []string{},
+			LoggingConfig: &types.LoggingConfig{
+				ApplicationLogLevel: "INFO",
+				LogFormat:           types.LogFormatJson,
+				LogGroup:            aws.String("/aws/lambda/test"),
+				SystemLogLevel:      "INFO",
+			},
+			MemorySize: aws.Int32(128),
+			SnapStart: &types.SnapStart{
+				ApplyOn: types.SnapStartApplyOnNone,
+			},
+			Timeout: aws.Int32(3),
+			TracingConfig: &types.TracingConfig{
+				Mode: types.TracingModePassThrough,
+			},
+		},
+	},
+}
+
+func TestFillDefaultValues(t *testing.T) {
+	for _, tt := range testCasesFillDefaultValues {
+		t.Run(tt.name, func(t *testing.T) {
+			lambroll.FillDefaultValues(tt.in)
+			in := lambroll.ToJSONString(tt.in)
+			expect := lambroll.ToJSONString(tt.expect)
+			if diff := cmp.Diff(in, expect); diff != "" {
+				t.Errorf("differs: (-got +want)\n%s", diff)
+			}
+		})
+	}
+}
diff --git a/utils.go b/utils.go
index 562796b..de5e3eb 100644
--- a/utils.go
+++ b/utils.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/Songmu/prompter"
+	"github.com/aws/aws-sdk-go-v2/aws"
 	"github.com/google/go-jsonnet/formatter"
 )
 
@@ -113,7 +114,7 @@ func resolveLogGroup(fn *Function) string {
 	if fn.LoggingConfig != nil && fn.LoggingConfig.LogGroup != nil {
 		return *fn.LoggingConfig.LogGroup
 	}
-	return fmt.Sprintf("/aws/lambda/%s", *fn.FunctionName)
+	return fmt.Sprintf("/aws/lambda/%s", aws.ToString(fn.FunctionName))
 }
 
 func fullQualifiedFunctionName(name string, qualifier *string) string {